ALBERT

Description: ABSTRACT Atmospheric models such as the Weather Research and Forecasting (WRF) model provide a tool to evaluate the behavior of regional hydrological cycle components, including precipitation, evapotranspiration, soil water storage and runoff. Recent model developments have focused on coupled atmospheric‐hydrological modeling systems, such as WRF‐Hydro, in order to account for subsurface, overland, and river flow and potentially improve the representation of land‐atmosphere interactions. The aim of this study is to investigate the contribution of lateral terrestrial water flow to the regional hydrological cycle, with the help of a joint soil‐vegetation‐atmospheric water tagging (SVA‐TAG) procedure newly developed in the so‐called WRF‐tag and WRF‐Hydro‐tag models. An application of both models for the high precipitation event on 15 August 2008 in the German and Austrian parts of the upper Danube river basin (94,100 km2) is presented. The precipitation that fell in the basin during this event is considered as a water source, is tagged and subsequently tracked for a 40 month‐period until December 2011. At the end of the study period, in both simulations, approximately 57% of the tagged water has run off, while 41% has evaporated back to the atmosphere, including 2% that has recycled in the upper Danube river basin as precipitation. In WRF‐Hydro‐tag, the surface evaporation of tagged water is slightly enhanced by surface flow infiltration, and slightly reduced by subsurface lateral water flow in areas with low topography gradients. This affects the source precipitation recycling only in a negligible amount.

Description: Abstract Snow acts as a vital source of water especially in areas where streamflow relies on snowmelt. The spatio‐temporal pattern of snow cover has tremendous value for snowmelt modeling. Instantaneous snow extent can be observed by remote sensing. Cloud cover often interferes. Many complex methods exist to resolve this, but often have requirements which delay the availability of the data and prohibit its use for real‐time modeling. In this research, we propose a new method for spatially modeling snow cover throughout the melting season. The method ingests multiple years of MODIS snow cover data and combines it using principal component analysis (PCA) to produce a spatial melt‐pattern model. Development and application of this model relies on the inter‐annual recurrence of the seasonal melting pattern. This recurrence has long been accepted as fact, but to our knowledge has not been utilized in remote sensing of snow. We develop and test the model in a large watershed in Wyoming using 17 years of remotely sensed snow cover images. When applied to images from two years that were not used in its development, the model represents snow covered area with accuracy of 84.9‐97.5% at varied snow covered areas. The model also effectively removes cloud cover if any portion of the interface between land and snow is visible in a cloudy image. This new PCA method for modeling the inter‐annually recurring spatial melt pattern exclusively from remotely sensed images possesses its own intrinsic merit, in addition to those associated with its applications.

Description: Abstract The development of the unconventional gas and CO2 sequestration is moving to deep formations. Because of the small flow pathways in the matrix, the Knudsen number might be high even though the gas is dense. In fact, due to the relatively high pressure at in situ conditions, gas flow in microfractures usually manifests a strong slip and nonideal gas effects. Therefore, understanding the coupling mechanism of these two on gas flow in rough‐walled microfractures is required to accurately model subsurface flow behavior. In this study, pressure‐driven gas flow in rough‐walled microfracture is analyzed in depth. Starting from the local governing equations for gas flow, a local flow model that includes gas slip and nonideal gas effects is derived by solving the Stokes equation with a first‐order slip boundary condition. Focusing at the representative elementary volume scale, the upscaled solutions to gas flow in a fracture with sinusoidal surface are derived to obtain the apparent permeability. The impact of nonideal gas effects, fracture roughness and aperture, and the tangential momentum accommodation coefficient on CH4 and CO2 flow is analyzed. The results show that fracture roughness introduces a high degree of heterogeneity in gas flow. At in situ conditions effects of gas slip, fracture roughness and tangential momentum accommodation coefficient on gas flow are reduced. The ideal gas law is capable of estimating CH4 flow to some extent. However, it fails to estimate CO2 flow in microfractures.

Description: Abstract In recent years, climatology, variability, hydrological impact, and climatic drivers of atmospheric rivers (ARs) are widely explored based on various AR identification algorithms. Different algorithms, varying in their tracing variables, thresholds, and geometric metrics criteria, will introduce uncertainty in further study of AR. Herein, a novel AR identification algorithm is proposed to address some current limitations. A coupled quantile and Gaussian kernel smoothing technique is proposed to make a balance in capturing the spatiotemporal variation of integrated water vapor transport climatology and avoiding largely biased estimation. In spite of variety of AR shape, orientation, and curvature, more reliable AR metrics (e.g., length and width) can be calculated based on the generated smooth AR trajectory, which is realized by modifying and integrating the concepts of local regression and K‐nearest neighbors. An unprecedented and novel metric (i.e., turning angle series) is delivered to quantify AR curvature, serves as the key to distinguish tropical cyclone‐like features, which often indicate occurrences of tropical cyclones. It also bridges ARs to their associated atmospheric circulation patterns. A pilot application of the algorithm is presented to identify persistent AR events related to flood triggering extreme precipitation sequences in the Yangtze River Basin (YRB). A dominating AR route, which connects Arabian Sea, Bay of Bengal, South China Sea, to Southeast China and YRB, terminates in the North Pacific, is found principal to the flood triggering extreme precipitation sequences in the YRB. In addition, this algorithm is extensible to other regions, even global domain.

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 125〈/p〉 〈p〉Author(s): Ahmet Hilmi Deringöl, Esra Mete Güneyisi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study investigates the influence of the friction pendulum bearing (FPB) isolator characteristics on the nonlinear response of the buildings under various seismic excitations. To represent a wide range of assessment, 3, 6, and 9-storey steel framed buildings with twenty seven different isolation models of FPB were studied by identifying the local and global deformations. Three important parameters such as isolation period T (as 2, 2.5, and 3 s), effective damping ratio ß (as 0.05, 0.15, 0.25), and yield strength ratio Fy/W (as 0.025, 0.05, and 0.10) were used in the modelling of FPB. Two-dimensional model of the base-isolated steel frames were created and the nonlinear time history analysis was performed through a number of earthquake ground motions. The behaviour of the isolated frames was measured by the variation of isolator displacement, roof drift ratio, relative displacement, interstorey drift ratio, absolute acceleration, base shear, base moment, hysteretic curve, and dissipated energy. The benefits obtained through the adoption of the base isolation system were discussed. It was found that the seismic response of the base-isolated frames could be estimated accurately by adjusting the proper isolation period, yield strength ratio, and effective damping ratio for the case studied structures.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 125〈/p〉 〈p〉Author(s): Jinbao Yao, Rutao Zhao, Nan Zhang, Dujuan Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉An in-filled trench barrier is usually used to reduce the damages from train-induced environmental vibrations. To find the vibration isolation effect of an in-filled trench barrier, this paper analyses the reflection coefficients and transmission coefficients of the Rayleigh wave at the interface between in-filled trenches and the soil. In our calculation formulas of ground vibrations, a single point and a single frequency excitation, as well as multi-point and multi-frequency excitation, are simultaneously derived in a soil-in-filled-trench system.〈/p〉 〈p〉Using these formulas and a numerical analysis, the effects of an in-filled trench barrier on the environmental vibrations induced by running trains are analyzed. The results show that the reflection coefficients increase, while the transmission coefficients decrease, with the density and elastic modulus of the in-filled material. The vibration isolation effect is clearly better than that without trenches. In a certain width range, the transmission coefficient and vertical acceleration levels decrease with the increase of trench width. The influences of the transmission coefficient and the vibration isolation effects are not clear with the trenches’ depth variation. The vertical vibrations of the ground pick-up point are all smaller than those without in-filled trenches.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 124〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 125〈/p〉 〈p〉Author(s): Benshun Shao, Stephen A. Mahin, Victor Zayas〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉By interpreting the seismic responses of two seismically isolated low-rise case-study buildings probabilistically using FEMA P695 methodology, the study indicates for the design of seismically isolated structures, providing isolator capacities equal to risk-targeted maximum considered earthquake (MCE〈sub〉R〈/sub〉) demand does not achieve targeted levels of reliability specified in ASCE 7–16. To do so, isolation system capacities beyond average MCE〈sub〉R〈/sub〉 demand are required. The minimum required capacities for using three types of enhanced isolation system (isolator without displacement restraint, isolator combined with external hard-stopping mechanism, and isolator with internal stiffening behavior at large horizontal displacement) are calculated with nonlinear response history analysis following probabilistic framework for different design risk categories numerically. The results indicate that isolator displacement capacities ranging from 1.5 to 2.60 times the average MCE〈sub〉R〈/sub〉 demand and isolation system shear capacities ranging from 1.5 to 5 times the average MCE〈sub〉R〈/sub〉 demand are required, depending on seismic risk categories and isolation system types. The use of an isolator with internal stiffening behavior is an efficient option to provide the required capacities for achieving reliability goals, especially for high risk-category design.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 8 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment〈/p〉 〈p〉Author(s): Julie A. Fortin, Jeffrey A. Cardille, Elijah Perez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The ongoing march toward freely available, highly pre-processed satellite imagery has given both researchers and the public unprecedented access to a vast and varied data stream teeming with potential. Among many sources, the multi-decade Landsat archive is certainly the best known, but legacy and current data from other sensors is available as well through the USGS data portals: these include CBERS, ASTER, and more. Though the particular band combinations or non-global missions have made their integration into analyses more challenging, these data, in conjunction with the entire Landsat record, are available to contribute to multi-decade surveys of land-cover change.〈/p〉 〈p〉With the goal of tracing forest change through time near the Roosevelt River in the state of Mato Grosso, Brazil, we used BULC and Google Earth Engine to fuse information from 13 space-borne imagers capturing 140 images spanning 45 years. With high accuracy, the resulting time series of classifications shows the timing and location of land-use/land-cover change—both deforestation and regrowth—at sub-annual time scales. Accuracy estimates showed that the synthesized BULC classification time series was better than nearly all of the single-day image classifications, covering the entire study area at sub-annual frequency while reducing the impact of clouds and most unwanted noise as it fused information derived from a wide array of imaging platforms. The time series improved and gradually sharpened as the density of observations increased in recent decades, when there were three or more clear, higher-resolution views of a pixel annually from any sensor combination. In addition to detailing the methodology and results of multi-source data fusion with the BULC approach, this study raises timely points about integrating information from early satellite data sources and from sensors with footprints smaller than Landsat's. There are decades of research deriving sensor-specific techniques for classifying land use and land cover from a single image in a variety of settings. The BULC approach leverages the many successes of single-sensor research and can be used as a straightforward, complementary tool for blending many good-quality mapped classifications from disparate sources into a coherent, high-quality time series.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 ISPRS Journal of Photogrammetry and Remote Sensing, Volume 154〈/p〉 〈p〉Author(s): 〈/p〉

Description: Abstract A storage‐discharge relation tells us how discharge will change when new water enters a hydrologic system, but not which water is released. Does an incremental increase in discharge come from faster turnover of older water already in storage? Or are the recent inputs rapidly delivered to the outlet, ‘short‐circuiting’ the bulk of the system? Here I demonstrate that the concepts of storage‐discharge relationships and transit time distributions can be unified into a single relationship that can usefully address these questions: the age‐ranked storage‐discharge relation. This relationship captures how changes in total discharge arise from changes in the turn‐over rate of younger and older water in storage, and provides a window into both the celerity and velocity of water in a catchment. This leads naturally to a distinction between cases where an increase in total discharge is accompanied by an increase (old water acceleration), no change (old water steadiness), or a decrease in the rate of discharge of older water in storage (old water suppression). The simple theoretical case of a power‐law age‐ranked storage‐discharge relations is explored to illustrate these cases. Example applications to data suggest that the apparent presence of old water acceleration or suppression is sensitive to the functional form chosen to fit to the data, making it difficult to draw decisive conclusions. This suggests new methods are needed that do not require a functional form to be chosen, and provide age‐dependent uncertainty bounds.

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 232〈/p〉 〈p〉Author(s): Yue Ma, Nan Xu, Jinyan Sun, Xiao Hua Wang, Fanlin Yang, Song Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Currently, 〈em〉in-situ〈/em〉 data and the time duration of altimeter data are limitations in calculating the water level and water volume of lakes and reservoirs from remotely sensed data. A novel method is proposed to estimate the temporal change in water levels and water volumes for lakes with only remotely sensed data. First, the surface profiles, including the ground and the underwater bottom, were extracted from the MABEL (Multiple Altimeter Beam Experimental Lidar) photon-counting lidar raw data via a new surface detecting algorithm. Second, the lake boundaries between land and water in different years were identified using a thresholding method based on the annual median Landsat composite. Third, water levels were calculated by matching the lidar surface profiles with the lake boundaries based on the nearby georeferenced coordinates. Finally, the water volumes in different years were estimated via the contours (i.e., lake boundaries) with different elevations. Lake Mead was selected as the study area, which is the largest reservoir in the United States in terms of water capacity. With only one day measuring lidar points in February 2012 and over 20 years of Landsat images (from 1987 to 2007), the water levels and water volumes in different years were estimated and compared with the 〈em〉in-situ〈/em〉 data. Our results performed well in accordance with the 〈em〉in-situ〈/em〉 measurements; the R-square of the water levels and water volumes were both over 0.99; the RMSE of the interannual variations of water levels and water volumes were 0.96 m and 0.31 km〈sup〉3〈/sup〉, respectively. The MABEL was used as a technology demonstrator for the satellite photon-counting laser altimeter and had similar data to the ICESat-2 dataset. Future ICESat-2 datasets will broaden this method to estimate water volumes for remote lakes from the 1980s, where no 〈em〉in-situ〈/em〉 data are available (such as the Tibetan Plateau and polar regions with thousands of remote and wild lakes), which could not be achieved in previous studies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 50〈/p〉 〈p〉Author(s): Zhengrong Li, Haowei Xing, Godfried Augenbroe〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Although there have been numerous studies on the evaluation of models that estimate sky diffuse radiation on inclined surfaces, it is still difficult for investigators to select from available sky diffuse radiation models for urban microclimate and building performance simulation. This is due to the fact that results from different studies are not consistent, or even contradictive, which indicates the fact that the evaluation criterion itself has a great effect on the performance of the model.〈/p〉 〈p〉To explore the effect of different evaluation criteria on the performance rating of the models, four evaluation methods are applied in this paper: diffuse irradiance on facades with respect to sky condition, diffuse irradiance on facades with respect to orientation, diffuse irradiance distribution among sky dome with respect to sky condition and diffuse irradiance on buildings in obstructed environment. Based on a statistical test on available data, Igawa model is considered to be the most accurate and appropriate model for urban and building energy simulation. Besides, an evaluation criterion appropriate for screening sky diffuse models for urban and building energy simulation is proposed. Furthermore, potential errors that may occur in the measurement and the corresponding quality control is presented.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Naval Architecture and Ocean Engineering〈/p〉 〈p〉Author(s): Jinglei Yang, Zhuang Lin, Ping Li, Zhiqun Guo, Hanbing Sun, Dongmei Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The partial air cushion supported catamaran (PACSCAT) is a novel surface effect ship (SES) and possesses distinctive resistance performance due to the presence of planing bottom. In this paper, the design of PACSCAT and air cushion system are described in detail. Model tests were carried out for Froude numbers ranging from 0.1 to 1.11, the focus is on the influence of air cushion system on resistance characteristics. Drag-reducing effect of air cushion system was proved by means of contrast tests in cuhionborne and non-cushionborne mode. Wave-making characteristics reflect that the PACSCAT would eventually enter planing regime, in which the air could just escape under the seals and the hull body could operate in a steady state. To acquire different air cushion pressure, air flow rate and leakage height were adjusted during tests. Experimental results show that the resistance performance in planing regime would decrease evidently as the increased air flow rate, however, the scheme with medium leakage height presents the best resistance performance in the hump region.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soils and Foundations〈/p〉 〈p〉Author(s): Toshihiro Noda, Tomohiro Toyoda〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Most soil–water coupled analyses of saturated soil are based on the 〈strong〉〈em〉u〈/em〉〈/strong〉–〈em〉p〈/em〉 formulation, where a set of equations is reduced by assuming that the acceleration of the fluid phase relative to that of the solid phase is less than that of the solid phase. Therefore, this analysis cannot be used for a coupled analysis with dynamic water flow in highly permeable soil. This study aims to present a soil–water coupled finite deformation analysis method based on full formulation, or 〈strong〉〈em〉u〈/em〉〈/strong〉–〈strong〉〈em〉w〈/em〉〈/strong〉–〈em〉p〈/em〉 formulation. This method differs from conventional methods in the following ways: (1) the governing equations explicitly include the equation of motion for the fluid phase, (2) a relative convective term is used to describe a change in the relative configuration between the two phases, and (3) the moving/inclined discharge boundary is directly implemented to the discretized governing equations. Herein, one/two dimensional seepage and plane-strain deformation analysis results are reported. In the seepage analysis, accelerating permeation of pore water is obtained and the undrained constraint condition is verified. In the deformation analysis, dynamic migration in a high permeable soil specimen, i.e., wave propagation and rotational flow of pore water, is observed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Johnson U. Kitheka〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉This study was undertaken in the Athi-Sabaki river basin in Kenya in East Africa.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The study focused on the determination of the influence of streamflow variability on salt fluxes. This involved monitoring of river discharge and river salinity in the period between 2012 and 2018.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉: This study demonstrates that Athi-Sabaki river discharges significant quantity of salt to the sea. There are significant seasonal and inter-annual variations in salt fluxes that are due to variations in river discharge and rainfall in the basin. The relationship between streamflow variations and variations of salinity in the river was inverse with highest salinity concentrations and fluxes occurring during low flow conditions. The river salinity and TDS concentrations decreased with an increase in river discharge due to dilution effect and flushing of salt from the river. The highly polluted sub-basins draining through the City of Nairobi exhibited relatively higher salinity and salt fluxes as compared to non-polluted ones draining rural areas. The total salt flux in the basin ranged between 29 × 10〈sup〉3〈/sup〉 and 261 × 10〈sup〉3〈/sup〉 tons year〈sup〉−1〈/sup〉. The relatively high salinity and salt fluxes were attributed to the discharge of wastewaters, seepage of groundwater and irrigation return flows. The study calls for water pollution control, sustainable irrigation and landuse practices in the basin.〈/p〉 〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soils and Foundations〈/p〉 〈p〉Author(s): Yiqun Tang, Siqi Xiao, Yangjie Zhan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉More and more excavation projects are being performed near existing buildings and structures due to large-scale urban construction, in which the excavation unavoidably causes settlement and potential danger to the surrounding construction and buildings. For linear traffic facilities parallel to the excavation, the settlement profile parallel to the excavation, namely, the settlement along the traffic line, should also be considered. Moreover, the precise control of the differential settlement along the traffic lines also plays a very important role. Thus, it is necessary to establish a quick prediction model, which is able to consider both vertical and parallel settlement profiles, using the basic information on the excavation. Based on the large amount of field data, the characteristics of the settlement profiles are analyzed. A simplified empirical method is proposed; it is established based on the Rayleigh and Gauss distribution functions for predicting the ground settlement along railways induced by an excavation. Meanwhile, back-propagation neural networks are also used to predict the settlement behavior. A comparison between the predicted results and the monitoring data is given to verify the feasibility of the proposed method. A good agreement indicates that the proposed method can be employed to predict the settlement along railways due to an adjacent excavation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 50〈/p〉 〈p〉Author(s): D. Koteswara Rao, D. Chandrasekharam〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sustainable conservation of natural resources has become a primary concern for urban cities, globally as they are centers of consumption and economy. Due to population growth, cities depend more on imports of food, energy, water, and services from all over the globe, and consume more virtual water than direct water, because of their food habits and lifestyle. Most of the imported goods are water intensive and pose challenges in tracing the source of virtual water. The goal of this research is to develop a general framework to assess the water footprint (WF) of a typical city in India using existing databases. A consumer-centric approach has been adopted for assessing WF in Hyderabad Metro Development Area (HMDA). The variation of the WF across economic classes of consumers is also analyzed. The WF is estimated based on four broad categories: 1) food consumption, 2) fossil fuels based energy, 3) electric power, and 4) direct water. Average WF of HMDA region is 1041 m〈sup〉3〈/sup〉/cap/year (2852 LPCD), in which 70% (1986 LPCD) of WF was consumed by food, 25% (744 LPCD) by electric power, only 4% (121 LPCD) is from direct water consumption and surprisingly the contribution from fossil fuel WF to total per capita WF of HMDA area is less than 1%.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society〈/p〉 〈p〉Author(s): Shuqin Chen, Xiyong Zhang, Shen Wei, Tong Yang, Jun Guan, Wenxiao Yang, Lijuan Qu, Yunqing Xu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Accurate grasp of district power demand is of great significance to both sizing of district power supply and its operation optimization. In this study, an index system has been established and visualized through a Geographic Information System, for revealing both temporal and spatial characteristics of district power loads caused by heating/cooling systems, including load level and fluctuation characteristics, spatial distribution of electric loads, and load coupling relationships between individual buildings and the district. Principal component analysis was applied to identify the buildings with significant impact on district load management. Using this method, the spatial-temporal characteristics of electric loads caused by heating in one university campus in China were analyzed. The results showed that building type and the operation modes had great effects on the level and volatility of the district electric load caused by heating. Buildings with high load levels and strong coupling with the peak district electric load, such as academic buildings, often had a major impact on the power demand of the district. Therefore, they were considered as key targets for energy-saving renovation and operation optimization. Buildings with large load fluctuation, such as teaching buildings, could contribute to the peak load shaving by adjusting the heating systems’ operation.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 50〈/p〉 〈p〉Author(s): Shuo-Jun Mei, Zhiwen Luo, Fu-Yun Zhao, Han-Qing Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Urban ventilation is important for building a healthy urban living environment. 2-D CFD simulation has been used widely for street canyon ventilation due to its high computational efficiency, but its applicability for a 3-D simulation has never been studied. This paper tried to answer the question: if and under what conditions, the widely-adopted 2-D CFD simulations on street canyon ventilation can represent a 3-D scenarios? 3-D simulations on street canyons with various street lengths and corresponding 2-D simulations are carried out with RNG 〈em〉k〈/em〉-〈em〉ε〈/em〉 model. Our study identified two important ventilation mechanism for controlling ventilation and dispersion in a 3-D street canyon, i.e., canyon vortex on the canyon top and the corner vortices at the street ends. The relative importance of these two driving forces will change with the street length/street width ratio (〈em〉B/W〈/em〉). For isolated street canyon, when 〈em〉B/W〈/em〉 is higher than 20 (for 〈em〉H/W〈/em〉 = 1) and 70 (〈em〉H/W〈/em〉 = 2), the street canyon ventilation will be dominated by canyon vortex, and 3-D street canyon ventilation could be simplified as a 2-D case. For multiple street canyon, the threshold of 〈em〉B/W〈/em〉 will become 20 when 〈em〉H/W〈/em〉 = 1, and 50 when 〈em〉H/W〈/em〉 = 2. The findings in this study could improve our approaches for simulating urban ventilation.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 50〈/p〉 〈p〉Author(s): Gaofeng Gu, Dujuan Yang, Tao Feng, Harry Timmermans〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The increasing shift of individuals to use new electric mobility tools like electric cars (EV) and electric bikes has changed household energy expenditure. It may also affect households’ investments in renewable energy equipment, i.e. solar panels, heat pumps. Relatively little research has been conducted on how the decision to purchase electric vehicles affects the decision to invest in home renewable energy equipment. This paper, therefore, aims to examine the effects of mobility tools decisions on the intention to invest in solar panels and heat pumps, based on the data collected through a stated choice experiment. A mixed logit model is estimated to capture unobserved heterogeneity among individuals. Results show that mobility tools significantly influence the choice of home renewable energy equipment. Households who prefer to purchase electric vehicles have a higher probability to invest in solar panels and heat pumps than households who prefer other mobility tools. In addition, EV adopters’ intention to invest in solar panels are stronger than the intention to invest in heat pumps. This suggests that electric vehicle users are likely the early adopters of solar panels.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 50〈/p〉 〈p〉Author(s): Heictor Correia Maioli, Raíssa Corrêa de Carvalho, Denise Dumke de Medeiros〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The increase in population concentration in large cities is a trend in the world, which brings several problems. In the context of urban mobility, bicycle sharing systems deserve special mention due to the impact and growth worldwide. The dissemination and success of these systems are also linked to aspects related to quality in their provision. Thus, this paper aims to conduct a study in the context of bicycle sharing to help managers to stimulate the use of this service and contribute to the development of sustainable cities. The SERVPERF tool was adapted and used to assess the quality of bicycle sharing service, in addition to identify which aspects impact on users’ satisfaction. This approach is innovative since there is a gap in the literature about customer satisfaction analyzes and aspects related to the quality of bicycle sharing service. In this way, this study can contribute to the dissemination of this service and to the solution of urban mobility problems by identifying the aspects considered as most important for the customers and thus improving these aspects. Therefore, the bicycle sharing system may have the increasingly use and will help to reduce urban mobility problems.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 5 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part A: Policy and Practice〈/p〉 〈p〉Author(s): Amit Agarwal, Dominik Ziemke, Kai Nagel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bicycle is a sustainable low-carbon transport mode. However, insufficient or unplanned infrastructure leads to decrease in the share of bicycle in many cities of developing nations. In order to increase the bicycle share and to provide safer, faster and more direct routes, a bicycle superhighway is proposed for urban areas. This study identifies the potential of increase in the bicycle share. For maximum utilization of the new infrastructure, an algorithm is presented to identify the optimum number and locations of the connectors between proposed new infrastructure and existing network. Household income levels are incorporated into the decision making process of individual travellers for a better understanding of the modal shift. A real-world case study of Patna, India is chosen to show the application of the proposed superhighway. It is shown that for Patna, the bicycle share can escalate as high as 48% up from 32% by providing this kind of infrastructure. However, together with bicycles, allowing motorbikes on the superhighway limits the bicycle share to 44%. The increase in bicycle share is mainly a result of people switching from motorbike, public transport and walk to the bicycle. Further, to evaluate the benefits of the bicycle superhighway, this study first extends an emission modelling tool to estimate the time-dependent, vehicle-specific emissions under mixed traffic conditions. Allowing only bicyclists on the superhighway improves congested urban areas, reduces emissions, and increases accessibility. However, allowing motorbikes on the superhighway increases emissions significantly in the central part of the urban area and reduces accessibilities by bicycle mode to education facilities which are undesirable. This study elicits that a physically segregated high-quality bicycle superhighway will not only attract current non-cyclist travellers and increase the share of the bicycle mode, but will also reduce negative transport externalities significantly.〈/p〉〈/div〉 〈/div〉

Description: Abstract Hydrogeological field studies rely often on a single conceptual representation of the subsurface. This is problematic since the impact of a poorly chosen conceptual model on predictions might be significantly larger than the one caused by parameter uncertainty. Furthermore, conceptual models often need to incorporate geological concepts and patterns in order to provide meaningful uncertainty quantification and predictions. Consequently, several geologically‐realistic conceptual models should ideally be considered and evaluated in terms of their relative merits. Here, we propose a full Bayesian methodology based on Markov chain Monte Carlo (MCMC) to enable model selection among 2D conceptual models that are sampled using training images and concepts from multiple‐point statistics (MPS). More precisely, power posteriors for the different conceptual subsurface models are sampled using sequential geostatistical resampling and Graph Cuts. To demonstrate the methodology, we compare and rank five alternative conceptual geological models that have been proposed in the literature to describe aquifer heterogeneity at the MAcroDispersion Experiment (MADE) site in Mississippi, USA. We consider a small‐scale tracer test (MADE‐5) for which the spatial distribution of hydraulic conductivity impacts multilevel solute concentration data observed along a 2D transect. The thermodynamic integration and the stepping‐stone sampling methods were used to compute the evidence and associated Bayes factors using the computed power posteriors. We find that both methods are compatible with MPS‐based inversions and provide a consistent ranking of the competing conceptual models considered.

Description: Abstract Laboratory experiments examined the impact of model vegetation on wave‐driven resuspension. Model canopies were constructed from cylinders with three diameters (d = 0.32, 0.64, and 1.26 cm) and 12 densities (cylinders/m2) up to a solid volume fraction (ϕ) of 10%. The sediment bed consisted of spherical grains with d50 = 85 μm. For each experiment, the wave velocity was gradually adjusted by increasing the amplitude of 2‐s waves in a stepwise fashion. A Nortek Vectrino sampled the velocity at z = 1.3 cm above the bed. The critical wave orbital velocity for resuspension was inferred from records of suspended sediment concentration (measured with optical backscatter) as a function of wave velocity. The critical wave velocity decreased with increasing solid volume fraction. The reduction in critical wave velocity was linked to stem‐generated turbulence, which, for the same wave velocity, increased with increasing solid volume fraction. The measured turbulence was consistent with a wave‐modified version of a stem‐turbulence model. The measurements suggested that a critical value of turbulent kinetic energy was needed to initiate resuspension, and this was used to define the critical wave velocity as a function of solid volume fraction. The model predicted the measured critical wave velocity for stem diameters d = 0.64 to 2 cm. Combining the critical wave velocity with an existing model for wave damping defined the meadow size for which wave damping would be sufficient to suppress wave‐induced sediment suspension within the interior of the meadow.

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 125〈/p〉 〈p〉Author(s): Alireza Daneshyar, Mohsen Ghaemian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A finite element model for seismic analysis of concrete arch dams is proposed. Material inelasticity as well as joints nonlinearity is considered. A damage-plastic formulation governs nonlinear behavior of concrete. Degeneration occurring during nonlinear behavior of concrete induces anisotropy into its microstructure. This anisotropy becomes more complex in seismic simulations, in which the state of stress expeditiously changes with time. Thus, anisotropic formulation is preferred over classical isotropic models. Utilizing rate-dependent anisotropic damage-plastic model, irreversible deformations, stiffness degeneration, induced anisotropy, closing/reopening of cracks, and viscous response of concrete are attained. Non-penetration condition, frictional behavior, and adhesion resulted by grouting of contraction and peripheral joints are also modeled in a coupled and rate-dependent manner. Different combinations of material and joints nonlinearities are used to model a system of dam-foundation-reservoir. The system is excited using three components of an earthquake, and effect of different sources of nonlinearities is investigated through comparison between results. In addition, capability of the anisotropic damage-plastic model is compared against an available isotropic formulation. A sensitivity analysis is also performed to investigate the effect of properties of joints on responses. Owing to high convergence rate of material and joints constitutive models, implicit time integration is employed, which leads to stable and accurate solutions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 125〈/p〉 〈p〉Author(s): Hongqiang Hu, Yu Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The spatial variability of soil properties has a significant effect on the seismic responses of sites. Considering that the probability density evolution method (PDEM), an efficient probabilistic methodology, has not been used in the probabilistic analysis with spatially variable soil properties before, the random field theory is incorporated to the traditional framework of PDEM to perform stochastic seismic response analysis of a soil profile. The stochastic seismic responses, including seismic deformation, surface ground motion, amplification factor and excess pore water pressure ratio, are obtained to quantify the effect of spatially variable soil properties. Probabilistic sensitivity analyses are also carried out to study the influence of spatial variability of different soil parameters and coefficients of variation on the ground motion in terms of probability density function. The results indicate that the random field model of shear modulus has a higher possibility of experiencing higher ground motion intensity than does friction angle.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 125〈/p〉 〈p〉Author(s): Huiling Zhao, Yong Yuan, Zhiming Ye, Haitao Yu, Zhiming Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The stiffness distribution of an atrium subway station with zero buried depth spatially varies when columns in the first level underground are removed and lateral beams replace the middle part of the floor slabs. It is pertinent to the mechanism and effects of multidirectional ground shaking on such structures. In this paper, the response characteristics of an atrium subway station subjected to bidirectional ground motions in a shaking table test were presented. Under horizontal seismic shaking, the structure, without a soil cover, showed a non-negligible rocking mode coupled with the well-known racking of the structure. Under vertical seismic shaking, the lateral beams, without supporting columns, demonstrated an obvious bending vibration associated with an overall up and downward movement. Overall, the horizontal component contributed more to dynamic response of the structure than the vertical component.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 125〈/p〉 〈p〉Author(s): Hector Guerrero, Vladimir Rodriguez, J. Alberto Escobar, Sergio M. Alcocer, Felipe Bennetts, Manuel Suarez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the reinforced concrete (RC) precast industry there is great concern about the seismic behavior of connections that emulate monolithic ones. Therefore, an experimental program was developed to examine the seismic performance of a particular RC precast connection type frequently used in industrial applications in comparison to monolithic connections. Tests were conducted on full scale. This paper presents and discusses the main results. Comparisons of a benchmark monolithic connection and six precast beam-column joints are presented. Precast connections were fabricated using different detailing, various levels of joint confinement, and post-tensioning. Test results are compared in terms of strength and deformation capacity, energy dissipation, and stiffness degradation. A relation between effective beam stiffness and inter-storey drift is found and compared to cracked stiffness modification factors recommended by design codes. Two effective stiffness models for reinforced concrete beams are proposed. Conclusions relevant to the precast construction industry have been formulated. Results show an acceptable performance of the tested precast system for seismic applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 4 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Ocean Engineering and Science〈/p〉 〈p〉Author(s): M. Mamun Miah, Aly R. Seadawy, H.M. Shahadat Ali, M. Ali Akbar〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we implement the generalized (〈em〉G〈/em〉′/〈em〉G〈/em〉)-expansion method established by Wang et al. to examine wave solutions to some nonlinear evolution equations. The method, known as the double (〈em〉G〈/em〉′/〈em〉G〈/em〉, 1/〈em〉G〈/em〉)-expansion method is used to establish abundant new and further general exact wave solutions to the (3+1)-dimensional Jimbo-Miwa equation, the (3+1)-dimensional Kadomtsev-Petviashvili equation and symmetric regularized long wave equation. The solutions are extracted in terms of hyperbolic function, trigonometric function and rational function. The solitary wave solutions are constructed from the obtained traveling wave solutions if the parameters received some definite values. Graphs of the solutions are also depicted to describe the phenomena apparently and the shapes of the obtained solutions are singular periodic, anti-kink, singular soliton, singular anti-bell shape, compaction etc. This method is straightforward, compact and reliable and gives huge new closed form traveling wave solutions of nonlinear evolution equations in ocean engineering.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 3 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Rock Mechanics and Geotechnical Engineering〈/p〉 〈p〉Author(s): Lamine Boumaiza, Ali Saeidi, Marco Quirion〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Among the methods used for evaluating the potential hydraulic erodibility of rock, the most common methods are those based on the correlation between the force of flowing water and the capacity of a rock to resist erosion, such as Annandale's and Pells' methods. The capacity of a rock to resist erosion is evaluated based on erodibility indices that are determined from specific geomechanical parameters of a rock mass. These indices include unconfined compressive strength (UCS) of rock, rock block size, joint shear strength, a block's shape and orientation relative to the direction of flow, joint openings, and the nature of the surface to be potentially eroded. However, it is difficult to determine the relevant geomechanical parameters for evaluating the hydraulic erodibility of rock. The assessment of eroded unlined spillways of dams has shown that the capacity of a rock to resist erosion is not accurately evaluated. Using more than 100 case studies, we develop a method to determine the relevant geomechanical parameters for evaluating the hydraulic erodibility of rock in unlined spillways. The UCS of rock is found not to be a relevant parameter for evaluating the hydraulic erodibility of rock. On the other hand, we find that the use of three-dimensional (3D) block volume measurements, instead of the block size factor used in Annandale's method, improves the rock block size estimation. Furthermore, the parameter representing the effect of a rock block's shape and orientation relative to the direction of flow, as considered in Pells' method, is more accurate than the parameter adopted by Annandale's method.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geodesy and Geodynamics, Volume 10, Issue 4〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Dagnachew Daniel Molla, Tenalem Ayenew Tegaye, Christopher G. Fletcher〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The volcano-tectonic lakes basin of Abaya-Chamo is part of the Main Ethiopian Rift system and exhibits large variations in geomorphology, physiography and climate between the rift floor and the plateau.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉Despite the importance of streamflow for water resources management and planning in the basin, many of the rivers there are ungauged. To make quantitative estimates of streamflow for spatially resolved water availability in such a highly heterogeneous environment, therefore, requires numerical modeling. This study is the first to quantify the surface and shallow groundwater resources in Abaya-Chamo, and to validate the physically fully distributed hydrologic model WetSpass under highly data-limited conditions, in a complex two-lake environment.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights〈/h6〉 〈p〉Simulated total river flow and estimated baseflow were verified at 15 gauging stations, with a good agreement. The WetSpass model is shown to be suitable for such a complex setting with a correlation coefficient of 0.95 and 0.97 for total flow and baseflow respectively at a statistically significant level (p-value 〈 0.05). The simulated annual water budget reveals that 74.6% of the 22.1 billion lit/yr in total precipitation in the basin is lost through evapotranspiration, 15.7% through surface runoff, and only 9.7% recharges the groundwater system. The simulations also revealed the surface runoff and groundwater recharge are the most sensitive to soil textural class, while evapotranspiration depends more strongly on land use.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581818302623-ga1.jpg" width="159" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): Valentin Haselbeck, Jannes Kordilla, Florian Krause, Martin Sauter〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Growing inorganic and expansive hydrochemical datasets and large differences in the measured concentrations require methods that are capable of compressing data without the loss of critical information and subsequently displaying it in a condensed and comprehensive way. Here we train an artificial neural network, Kohonen’s self-organizing map (SOM), to model inorganic hydrochemical clusters and associate the salinity source with the distribution of the ionic concentration spatial variation at a former potash mining site. Kohonen’s self-organizing maps are applied to project the data onto a two-dimensional grid and the geometric relationship of the projected vectors is subsequently used to perform a hierarchical cluster analysis. The SOM clustering approach succeeded in assigning the groundwater samples automatically according to their inorganic chemical composition. Five different clusters, three geogenic and two anthropogenic, were identified. The final outcome is displayed and compared with the classification from Piper plotting of the same dataset. In order to see the SOM clustering results in the large scale hydrogeological context, the distribution of the clusters is displayed spatially. This approach is a tool for the hydrogeologist to quickly analyze large datasets and present them in a clear and concise format.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Transport Geography, Volume 79〈/p〉 〈p〉Author(s): Saad AlQuhtani, Ardeshir Anjomani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Dependency on the automobile in the United States has been associated with many urban problems. As a result, many American cities have seen a rebound in public transportation systems—many of whom have built modern rail transit systems. This resurgence of rail transit systems has caused apparent shifts in economic, social, and spatial aspects of neighborhoods located in proximity to rail stations.〈/p〉 〈p〉This study investigates the changes in housing value between 2000 and 2014 in 454 block groups within a one-mile buffer around rail stations located in the Dallas-Fort Worth metropolitan area to determine if there is a correlation between proximity to rail stations and median housing value. This study uses two approaches to analyze the data. First, a comparison of changes in housing value within block groups located in the study area during the study period is introduced. Next, an innovative approach is employed to select the best regression model using the data on the block groups located within the study area to understand the relationships between the selected independent variables and the changes in housing value during the study period in relation to the research question.〈/p〉 〈p〉The findings demonstrate that economic development and commercial activity locations have the highest effect on housing value during the study period, and block groups that were closer to rail stations experienced lower changes in housing value compared to block groups located farther away from stations. An interesting finding contrary to some of the literature is that an increase in the percent of the black population does not have negative effects on the change in property values. The findings for Hispanic and other minorities is also the same. These findings are a useful addition to the existing literature and contribute to the field of urban planning to mitigate the effects on housing value surrounding station areas. In addition, planners and policymakers could use the implications from the findings to adopt some policies for furthering the success of rail transit systems in urban areas by sustaining station area development.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Transport Geography, Volume 78〈/p〉 〈p〉Author(s): Benjamin K. Sovacool, Johannes Kester, Lance Noel, Gerardo Zarazua de Rubens〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Despite a potentially revolutionary shift towards electric mobility in the passenger vehicle market, the academic and policymaking communities remain wedded to a techno-economic paradigm that may not fully appreciate deeper social and geographic elements of a transition to electric vehicles. In this paper, based primarily on bivariate statistical analysis as well as a hierarchical regression analysis of a survey distributed to 〉5000 respondents across Denmark, Finland, Iceland, Norway, and Sweden, we analyze how perceptions and attitudes towards electric vehicles and vehicle-to-grid technologies differ by income, political affiliation, and geography. Although our findings confirm EV ownership and mobility patterns in general are related to income—those with higher incomes both own more EVs and drive more generally—they also confirm that interest in EVs is not so strongly related. Lower income groups seem to ask less from their cars, thus potentially opening up a market for cheaper low-range alternates. Political orientation is correlated to car and EV ownership, with those on the “left” more interested yet those on the “right” more able and willing to buy expensive cars. Moreover, we see variation in preferences across urban and rural subcategories, and our findings strongly suggest that EVs need not be promoted only for city or suburban areas. When controlling for variables, a multilevel regression analysis does not change the overall thrust of these associations.〈/p〉〈/div〉 〈/div〉

Description: Abstract The impacts of aquatic vegetation on bed load transport rate and bedform characteristics were quantified using flume measurements with model emergent vegetation. First, a model for predicting the turbulent kinetic energy, kt, in vegetated channels from channel average velocity U and vegetation volume fraction ϕ was validated for mobile sediment beds. Second, using data from several studies, the predicted kt was shown to be a good predictor of bed load transport rate, Qs, allowing Qs to be predicted from U and ϕ for vegetated channels. The control of Qs by kt was explained by statistics of individual grain motion recorded by a camera, which showed that the number of sediment grains in motion per bed area was correlated with kt. Third, ripples were observed and characterized in channels with and without model vegetation. For low vegetation solid volume fraction (ϕ ≤ 0.012), the ripple wavelength was constrained by stem spacing. However, at higher vegetation solid volume fraction (ϕ=0.025), distinct ripples were not observed, suggesting a transition to sheet flow, which is sediment transport over a plane bed without the formation of bedforms. The fraction of the bed load flux carried by migrating ripples decreased with increasing ϕ, again suggesting that vegetation facilitated the formation of sheet flow.

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 ISPRS Journal of Photogrammetry and Remote Sensing, Volume 155〈/p〉 〈p〉Author(s): Sheng Wang, Andreas Baum, Pablo J. Zarco-Tejada, Carsten Dam-Hansen, Anders Thorseth, Peter Bauer-Gottwein, Filippo Bandini, Monica Garcia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Unlike satellite earth observation, multispectral images acquired by Unmanned Aerial Systems (UAS) provide great opportunities to monitor land surface conditions also in cloudy or overcast weather conditions. This is especially relevant for high latitudes where overcast and cloudy days are common. However, multispectral imagery acquired by miniaturized UAS sensors under such conditions tend to present low brightness and dynamic ranges, and high noise levels. Additionally, cloud shadows over space (within one image) and time (across images) are frequent in UAS imagery collected under variable irradiance and result in sensor radiance changes unrelated to the biophysical dynamics at the surface. To exploit the potential of UAS for vegetation mapping, this study proposes methods to obtain robust and repeatable reflectance time series under variable and low irradiance conditions. To improve sensor sensitivity to low irradiance, a radiometric pixel-wise calibration was conducted with a six-channel multispectral camera (mini-MCA6, Tetracam) using an integrating sphere simulating the varying low illumination typical of outdoor conditions at 55〈sup〉o〈/sup〉N latitude. The sensor sensitivity was increased by using individual settings for independent channels, obtaining higher signal-to-noise ratios compared to the uniform setting for all image channels. To remove cloud shadows, a multivariate statistical procedure, Tucker tensor decomposition, was applied to reconstruct images using a four-way factorization scheme that takes advantage of spatial, spectral and temporal information simultaneously. The comparison between reconstructed (with Tucker) and original images showed an improvement in cloud shadow removal. Outdoor vicarious reflectance validation showed that with these methods, the multispectral imagery can provide reliable reflectance at sunny conditions with root mean square deviations of around 3%. The proposed methods could be useful for operational multispectral mapping with UAS under low and variable irradiance weather conditions as those prevalent in northern latitudes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 232〈/p〉 〈p〉Author(s): P. Potapov, A. Tyukavina, S. Turubanova, Y. Talero, A. Hernandez-Serna, M.C. Hansen, D. Saah, K. Tenneson, A. Poortinga, A. Aekakkararungroj, F. Chishtie, P. Towashiraporn, B. Bhandari, K.S. Aung, Q.H. Nguyen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Spatially and temporally consistent vegetation structure time-series have great potential to improve the capacity for national land cover monitoring, to reduce latency and cost of international reporting, and to harmonize regional land cover characterizations. Here we present a semi-automatic, operational algorithm for mapping and monitoring of woody vegetation canopy cover and height at a regional scale using freely available Landsat time-series data. The presented algorithm employs automatic data processing and mapping using a set of lidar-based vegetation structure prediction models. Changes in vegetation cover are detected separately and integrated into the structure time-series. Sample-based validation and inter-comparison with existing datasets demonstrates the spatial and temporal consistency of our regional data time-series. The dataset reliably reflects changes in tree cover (tree cover loss user's accuracy of 0.84 and producer's accuracy of 0.75) and can serve as a tool to map annual forest extent (user's accuracy of 0.98 and producer's accuracy of 0.81 for 10% canopy cover threshold to define the forest class). The tree height estimates are consistent with a GLAS-based global map (mean average error of 3.7 m, the correlation coefficient of 0.92 and the R〈sup〉2〈/sup〉 of 0.85). The algorithm was prototyped within the Lower Mekong region where it revealed an intensive woody vegetation dynamic. Of the year 2000 forest area (defined using canopy cover threshold of 10% and tree height threshold of 5 m), 9.4% was deforested by the year 2017, and 16.6% was affected by stand-replacement disturbance followed by reforestation. The average annual area of stand-level forest disturbance within the region was 2.34 Mha, and increased by 34% from 2001 (1.85 Mha) to 2017 (2.48 Mha). Total forest area decreased by 6.2% within the region, and 11.1% of year 2000 primary forest area was lost by 2017. At the national level, Cambodia demonstrated the highest rate of deforestation, with a net forest area loss of 22.5%. We estimated that 21.3% of 2017 forest cover had an age of 17 years or less, illustrating the intensive forest land uses within the region. The time-series product is suitable for mapping annual land cover and inter-annual land cover change using customized class definitions. The regionally-consistent data are publicly available for download (〈a href="https://glad.umd.edu/" target="_blank"〉https://glad.umd.edu/〈/a〉), and online analysis (〈a href="https://rlcms-servir.adpc.net/en/forest-monitor/" target="_blank"〉https://rlcms-servir.adpc.net/en/forest-monitor/〈/a〉), and serve as an input to the SERVIR-Mekong Regional Land Cover Monitoring System.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 232〈/p〉 〈p〉Author(s): Peifeng Ma, Weixi Wang, Bowen Zhang, Jili Wang, Guoqiang Shi, Guangqing Huang, Fulong Chen, Liming Jiang, Hui Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As the world's largest city cluster, the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) is vulnerable to significant subsidence. The widely distributed sediments and rapid urbanization in the GBA result in the concurrence of large- and small-scale subsidence. Mono-sensor synthetic aperture radar (SAR) images usually suffer from the limitation of either low resolution or small coverage, and thus, are not applicable to completely monitoring the GBA. In this study, we used Sentinel-1 (S1), COSMO-SkyMed (CSK) and TerraSAR-X (TSX) images jointly to reveal multi-scale subsidence of the GBA. The overall subsidence ranged from 0 to 112.3 mm/yr derived from the 2015–2017 S1 images. Three regional subsidence bowls (Zhuhai–Zhongshan, Jiangmen, and Guangzhou–Zhongshan) formed in the western alluvial plain. The high correlation between regional subsidence and Quaternary sediments confirms that sediment consolidation is the main cause of subsidence. The land use and numerical modeling results suggest that groundwater extraction and artificial loading are the triggering factors. Two representative local subsidence cases were analyzed using high-resolution images: reclamation settlement at the Hong Kong International Airport (HKIA) and sinkhole subsidence due to the excavation of the Shenzhen Wenbo skyscraper foundation pit. The validation at the HKIA showed that the measurements from the CSK and S1 data both agreed well with the leveling data. However, CSK outperformed S1 in the sense that it increased the point density by a factor of 5, improved the height precision by a factor of 4, and showed fewer false alarms. CSK is therefore more applicable to monitoring the local subsidence of key infrastructures. The cross-heading tracks of TSX and CSK images detected precursory subsidence before the sinkhole collapse from two sides, indicating that the cross-heading tracks benefit the comprehensive monitoring of local subsidence in high-rise and high-density built environments. In summary, the synergistic use of multi-sensor SAR images demonstrates the practicability of the operational surveillance of multi-scale subsidence from regional surveying to the fine monitoring of local areas in the GBA.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 International Journal of Rock Mechanics and Mining Sciences, Volume 121〈/p〉 〈p〉Author(s): Ziyan Li, Derek Elsworth, Chaoyi Wang, Kyungjae Im〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We introduce a new miniature double direct shear (mini-DDS) apparatus, housed within a standard-triaxial (TEMCO) pressure vessel, capable of concurrently measuring the evolution of frictional strength, stability, healing and along-fault permeability under 〈em〉in situ〈/em〉 conditions of stress and temperature. The apparatus accommodates gouge samples (25 mm × 32 mm) and intact rock samples with confining and shear stresses and pore pressures up to ∼26 MPa. Permeability may be measured with applied flow rates ranging from 1.67 × 10〈sup〉−11〈/sup〉 to 3.6 × 10〈sup〉−6〈/sup〉 m〈sup〉3〈/sup〉/s to a flow accuracy of 0.5% representing a lower bound of permeability 〉2.2 × 10〈sup〉−18〈/sup〉 m〈sup〉2〈/sup〉. Sliding velocities are in the range 0.1 μm/s to 0.67 cm/s with a frame stiffness of 0.067 kN/μm. We describe protocols and procedures for calibration and experiments and note the potential of the apparatus for both rapid and extended-duration measurements of friction-permeability evolution and healing. The apparatus returns measurements of friction and stability of reference materials of F110 quartz consistent with the literature while additionally allowing the concurrent measurement of permeability. Permeability of F110 quartz evolves in slide-hold-slide (SHS) experiments with increases during holds and decreases during subsequent slides. These observations are consistent with grain crushing and resultant wear products that reduce that permeability by clogging during slides with unclogging of the major fluid channels occurring during shearing.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 ISPRS Journal of Photogrammetry and Remote Sensing, Volume 155〈/p〉 〈p〉Author(s): Peifeng Ma, Tao Li, Chaoyang Fang, Hui Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper analyzed the dynamic behaviors of a high-speed railway (HSR) bridge and evaluated the possibility of measuring the sub-millimeter settlement and uplift using COSMO-SkyMed images. The capability of synthetic aperture radar interferometry (InSAR) technologies with the purpose of sub-millimeter deformation monitoring without ground control points has rarely been studied. In this paper, we conducted a tentative test for measuring the sub-millimeter settlement and uplift of a HSR bridge. Persistent scatterer (PS) and distributed scatterer (DS) were jointly detected to increase the point density. The temperature model was introduced to separate the thermal expansion and linear deformation. By analyzing the HSR structure and time-series deformation, we infer that PS points correspond to double-bounce scatterers mainly generated by the interactions between the girder and track slab and between the girder and fender, and DS points correspond to single-bounce scatterers generated by the bridge girder surface. The accuracy of linear deformation velocity and time-series deformation were evaluated, respectively. Under the assumptions by qualitative analysis, the results demonstrate that COSMO-SkyMed is capable of achieving sub-millimeter accuracy in linear deformation velocity. However, the leveling validation implies that it is difficult to achieve sub-millimeter accuracy in time-series deformation because of the uncertainties from incorrect ground data, location and time difference between the InSAR and ground data, the presence of lateral deformation, improper removal of the atmospheric phase screen, and inconsistency between the air temperature and bridge temperature.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 ISPRS Journal of Photogrammetry and Remote Sensing, Volume 154〈/p〉 〈p〉Author(s): Hao Fang, Florent Lafarge〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Analyzing and extracting geometric features from 3D data is a fundamental step in 3D scene understanding. Recent works demonstrated that deep learning architectures can operate directly on raw point clouds, i.e. without the use of intermediate grid-like structures. These architectures are however not designed to encode contextual information in-between objects efficiently. Inspired by a global feature aggregation algorithm designed for images (Zhao et al., 2017), we propose a 3D pyramid module to enrich pointwise features with multi-scale contextual information. Our module can be easily coupled with 3D semantic segmentation methods operating on 3D point clouds. We evaluated our method on three large scale datasets with four baseline models. Experimental results show that the use of enriched features brings significant improvements to the semantic segmentation of indoor and outdoor scenes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 ISPRS Journal of Photogrammetry and Remote Sensing, Volume 155〈/p〉 〈p〉Author(s): Deepak Gautam, Arko Lucieer, Christopher Watson, Colin McCoull〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study addresses the correction of lever-arm offset and boresight angle, and field of view (FOV) determination to enable accurate footprint determination of a spectroradiometer mounted on an unmanned aircraft system (UAS). To characterise the footprint, an accurate determination of the spectroradiometer position and orientation (pose) must be acquired with a global navigation satellite system (GNSS) and an inertial measurement unit (IMU). Accurate pose estimation requires an accurate lever-arm and boresight correction between the pose measuring sensors and the spectroradiometer. Similarly, the spectroradiometer FOV is required to determine the footprint size as a function of above ground level (AGL) flying height. The system used in this study consists of an IMU with dual-frequency and dual-antenna GNSS receiver, a machine vision camera, and a point-measuring spectroradiometer (Ocean Optics QE Pro). The lever-arm offset was determined from a scaled 3D point cloud of the system, created using photos of the airframe and processed with the structure-from-motion (SfM) algorithm. The boresight angles were estimated with stationary experiments by computing the difference between the orientations of the IMU, the spectroradiometer, and the camera. The orientation of the spectroradiometer was determined by moving a spectrally distinct target into the FOV. The orientation of IMU was measured by averaging its readings during the stationary epoch, while SfM was employed as an independent technique to estimate the orientation of the camera. The footprint of the spectroradiometer for a combination of AGL height and Gershun tube aperture ring was determined experimentally, enabling computation of the effective FOV. In-flight validation of the lever-arm and boresight correction was performed by comparing the corrected pose of the co-mounted camera with the pose derived from SfM as the reference. Our experimental results demonstrate that controlled determination and correction of lever-arm and boresight increases the pose estimation accuracy and thereby supports the direct georeferencing of a UAS-mounted spectroradiometer point observation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 1 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Underground Space〈/p〉 〈p〉Author(s): Ying Xu, Yimiao Huang, Guowei Ma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Underground structures are normally located in highly confined and congested spaces which may trigger severe gas explosion accidents with significant human and economic losses. For accurately evaluating the explosion consequences, a variety of influences factors need to be considered including concentrations of gas mixtures, vent conditions, obstacles, and ignition features, etc. A good review on these influence factors is important for a better understanding of explosion behaviors, e.g. the deflagration to detonation phenomenon. This paper investigates some critical influencing factors for gas explosions in underground or confined spaces, and the effects of the factors on gas explosions in underground structures are discussed. The results and findings from literatures are discussed and remarked. The present paper provides a reference for future study on safety management and consequence mitigation of the underground gas explosions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology: Regional Studies, Volume 24〈/p〉 〈p〉Author(s): Zeinab Mohammadi Raigani, Kazem Nosrati, Adrian L. Collins〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Study region〈/h6〉 〈p〉The Kamish River catchment (308 km〈sup〉2〈/sup〉); a mountainous agricultural catchment under dry-land and rangeland farming located in Kermanshah province, in western Iran.〈/p〉 〈/div〉 〈div〉 〈h6〉Study focus〈/h6〉 〈p〉The main objective of this study was to apportion sub-basin spatial source relative contributions to target channel bed sediment samples using a composite fingerprinting procedure including a Bayesian un-mixing model. In total, thirty-four geochemical tracers, eleven elemental ratios and different weathering indices were measured or estimated for 43 tributary sediment samples collected to characterise three sub-basin spatial sediment sources and eleven target bed sediment samples collected at the outlet of the main basin. Statistical analysis was used to select three different composite signatures.〈/p〉 〈/div〉 〈div〉 〈h6〉New hydrological insights for the region〈/h6〉 〈p〉Using a composite signature based on KW-H and DFA, the respective relative contributions (with uncertainty ranges) from tributary sub-basins 1, 2 and 3 were estimated as 54.3% (47.8–62.0), 11.4% (4.2–18.7) and 34.3% (27.6–39.9), compared to 72.0% (61.6–82.7), 13.6% (9.0–18.5) and 14.2% (3.1–25.4) using a combination of KW-H and data mining, and 50.8% (42.8–59.9), 28.7% (20.2–37.3) and 20.3% (12.7–27.2) using a fingerprint selected by KW-H and PCCA. The root mean square difference between these source estimates highlighted sensitivity to the composite signatures. Evaluation of the un-mixing model predictions using virtual mixture tests confirmed agreement between modelled and known source proportions.〈/p〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S2214581819301247-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 2 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soils and Foundations〈/p〉 〈p〉Author(s): Afshin Kordnaeij, Reza Ziaie Moayed, Majid Soleimani〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cement production requires a lot of energy and is also one of the most important sources of carbon dioxide emissions. Consequently, the replacement of part of the cement with a more environmentally friendly material, such as zeolite, is of great importance. The present research involves the conducting of a series of laboratory tests on loose sand specimens (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈msub〉〈mi〉D〈/mi〉〈mi〉r〈/mi〉〈/msub〉〈mo〉≈〈/mo〉〈mn〉30〈/mn〉〈mo〉%〈/mo〉〈/mrow〉〈/math〉) grouted with cementitious materials (cement and zeolite) to investigate the effect of different parameters, such as the size of the sand particles, the ratio of water to cementitious materials (〈em〉W/CM〈/em〉) and the replacement of a certain percentage of the cement in the grout with zeolite (〈em〉Z〈/em〉), on the unconfined compressive strength (〈em〉UCS〈/em〉) of the grouted sand specimens. The results indicate that for all the grout 〈em〉W/CM〈/em〉 and sand grain sizes, when 〈em〉Z〈/em〉 is increased from zero zeolite (〈em〉Z〈sub〉0〈/sub〉〈/em〉), the 〈em〉UCS〈/em〉 initially increases. Then, after reaching an optimal amount (〈em〉Z〈sub〉30〈/sub〉〈/em〉), it decreases. Moreover, increasing both the size of the sand particles and the 〈em〉W/CM〈/em〉 of the grout is seen to reduce the 〈em〉UCS〈/em〉 of the grouted specimens. The 〈em〉UCS〈/em〉 of the grouted sand specimens increases with the equilibrium of 〈em〉SiO〈sub〉2〈/sub〉〈/em〉 and 〈em〉Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉〈/em〉 with 〈em〉CaO〈/em〉 elements in the grouting suspension. Finally, equations with a high performance are proposed to predict the 〈em〉UCS〈/em〉 of sands grouted with zeolite-cement using a multiple regression model (〈em〉MRM〈/em〉) and a group method of data handling (〈em〉GMDH〈/em〉)-type neural network.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 50〈/p〉 〈p〉Author(s): Zhijian Liu, Di Wu, Yuanwei Liu, Guangya Jin, Qiaomei Wang, Zhonghe Han, Hancheng Yu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Low energy buildings are an efficient approach to meet space heating requirements and saving energy. Studies of low energy buildings mainly focus on cold climate regions. However, there is less research on the feasibility of low energy buildings on Qinghai-Tibetan Plateau located in a severely cold climatic region. Therefore, a low energy building equipped with an integrated heating system was built on Qinghai-Tibetan Plateau. The performance of the low energy building was quantitatively evaluated by field measurement and dynamic TRNSYS simulation. To be specific, the indoor temperature and relative humidity were measured, and further served as the data to verify the accuracy of the simulated results. The results show that the temperature and humidity were above 20 °C and 40% in the heating season, in accordance with the regulated low energy building standard (DB63/T1682-2018). According to the TRNSYS simulation, the hourly indoor temperature and relative humidity were generally in the range of 20–24 °C and 34–56%, respectively, in the heating season, with an energy demand of 16.1 kW h/(m〈sup〉2〈/sup〉 year). Overall, the building performance meets the local low energy building standard (DB63/T1682-2018). Therefore, a passive building with integrated heating system assistance is feasible for pleasant indoor comfort on Qinghai-Tibetan Plateau. These findings could explore the application potential of low energy buildings in severe cold climate areas.〈/p〉〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part E: Logistics and Transportation Review, Volume 129〈/p〉 〈p〉Author(s): Christopher S. Tang, Lucas P. Veelenturf〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉By leveraging new technologies (Additive Manufacturing, Advanced Robotics, Artificial Intelligence, Autonomous Vehicles, Blockchain, Drones, Internet of Things, etc.), many companies are developing cyber-physical systems that can change the competition landscape. In the midst of this exciting development, we examine the strategic role of logistics and transportation services for creating economic, environmental and social values. Also, we discuss some new research directions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part E: Logistics and Transportation Review, Volume 129〈/p〉 〈p〉Author(s): Tsan-Ming Choi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Operations management (OM) is an important area in business and engineering, which can be regarded as a spinoff of Operations Research and Management Science (OR/MS). In Web of Science, 〈em〉Transportation Research – Part E: Logistics and Transportation Review〈/em〉 (TRE) is listed in the category of OR/MS. In fact, according to statistics and our editorial experience, about half of the papers submitted to TRE are classified as OM papers. Owing to the popularity of OM papers in TRE, this paper updates the editorial policy of TRE in the area of OM and highlights some points to help authors to successfully publish high quality and impactful papers in TRE.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part D: Transport and Environment, Volume 73〈/p〉 〈p〉Author(s): James H. Gawron, Gregory A. Keoleian, Robert D. De Kleine, Timothy J. Wallington, Hyung Chul Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although recent studies of autonomous taxis (ATs) have begun to explore potential environmental implications of fleet deployment, little is known about their impacts over the long term. We present a life-cycle assessment framework that incorporates both direct and indirect effects of ATs at the subsystem, vehicle, and mobility-system levels. Eco-driving and intersection connectivity are the direct effects analyzed along with indirect effects that include empty kilometers, parking, charging infrastructure, powertrain rightsizing, electric vehicle adoption, ride-sharing, and fleet-turnover rates. A case study of an AT fleet in Austin, Texas from 2020 to 2050 with constant travel demand indicates the strategic deployment of an electrified AT fleet can reduce cumulative energy and greenhouse gas (GHG) emissions by 60% in the base case, with a majority of this benefit resulting from electrified powertrains. Further reductions up to 87% can be achieved with accelerated electrical grid decarbonization, dynamic ride-share, longer vehicle lifetime, more energy efficient computer systems, and faster fuel efficiency improvements for new vehicles. We highlight the major opportunities for maximizing the environmental performance of AT fleets over the long term.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part C: Emerging Technologies, Volume 105〈/p〉 〈p〉Author(s): Jiaman Ma, Jeffrey Chan, Goce Ristanoski, Sutharshan Rajasegarar, Christopher Leckie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An important aspect of Intelligent Public Transportation Systems (IPTS) is providing accurate travel time information. Knowing arrival times of public vehicles in advance can reduce waiting times of passengers and attract more people to take public transport. Existing approaches have two main limitations in the field of bus travel time prediction. First, influenced by increasingly complex real-time traffic factors and sparsity of real-time data, bus travel times can be difficult to predict accurately in modern cities. Second, bus dwelling and transit times are predominantly affected by different factors and hence have different patterns, but little research focuses on how to divide dwelling and transit areas and to build independent models for them. Consequently, we propose a novel segment-based approach to predict bus travel times using a combination of real-time taxi and bus datasets, that can automatically divide bus routes into dwelling and transit segments. Two models are built to predict them separately by incorporating different impact traffic factors. We evaluate our approach using real-world trajectory datasets, collected in Xi’an, China during June 2017. Compared to existing methods, the experimental results reveal that our approach improves the accuracy of bus travel time prediction, especially under abnormal traffic conditions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part E: Logistics and Transportation Review, Volume 128〈/p〉 〈p〉Author(s): Zhixiang Chen, Bopaya Bidanda〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Based on two sustainable manufacturing strategies: resource recycling and emission reduction, this paper addresses a new production-inventory problem of multiple factories with JIT logistics, component recovery and emission control. Motivated by beer industry, we formulate this problem based on two decision mechanisms: (1) PI-CR decision mechanism–sole consideration of component recovery (component recycling) (2) PI-RE decision mechanism–joint consideration of component recycling and emission control. In the PI-RE decision mechanism, two emission control policies—carbon tax and carbon cap & trade are implemented. Numerical analysis is demonstrated to show the application of the models, and the managerial implications are put forward. Results show that emission control and resource recycling strategies have different impacts on the decision, increasing the return rate of recoverable component is an effective approach to currently reduce emissions and cost, while the cap & trade policy is more effect than the carbon tax policy in controlling emissions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part D: Transport and Environment, Volume 73〈/p〉 〈p〉Author(s): Ran Tu, Lama Alfaseeh, Shadi Djavadian, Bilal Farooq, Marianne Hatzopoulou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Communication between vehicles and road infrastructure can enable more efficient use of the road network and hence reduce congestion in urban areas. This improvement can be enhanced by distributed control due to its lighter computational load and higher reliability. Despite favourable impacts on traffic, little is known about the effects of such systems on near-road air quality. In this study, an End-To-End (E2E) dynamic distributed routing algorithm in Connected and Automated Vehicles (CAVs) was applied in downtown Toronto, to identify whether benefits to network throughput were associated with lower near-road NO〈sub〉2〈/sub〉 concentrations. We observe significant reductions in the emissions of Greenhouse Gases (GHGs) with increased penetration of CAVs. Nonetheless, at times, the emissions of nitrogen oxides (NO〈sub〉x〈/sub〉) increased with higher CAVs. Besides, a higher frequency and severity of NO〈sub〉2〈/sub〉 hot-spots were observed under a 100% CAV scenario. Impacts of the proposed system on electric energy consumption in a full electric vehicle network were also investigated, indicating that the addition of CAVs that are electric did not contribute to high energy savings. We propose that such new transformative technologies in transportation should be designed with air pollution and public health goals.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): Andrew C. Knight, Adrian D. Werner, Dylan J. Irvine〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Offshore fresh groundwater is increasingly suggested as a potential water resource for onshore human demands. In many cases, onshore pumping already draws significant fresh groundwater from offshore. However, offshore aquifers and the extent of offshore freshwater are usually poorly characterised due to data scarcity. This study combines geophysical data, hydraulic information and a first-order mathematical analysis to investigate offshore freshwater extent in the Gambier Embayment (Australia). A large seismic data set, combined with onshore and offshore bore-log geological profiles, are used to explore the regional offshore hydro-stratigraphy. Aquifer hydraulic parameters and onshore heads are obtained from onshore investigations. A novel application of Archie’s law, geophysical data and onshore hydrochemical data provide useful insights into the salinity profiles within four offshore wells. These are compared to steady-state, sharp-interface estimates of the freshwater extent obtained from a recently developed analytical solution, albeit using simplified conceptual models. Salinities derived from resistivity measurements indicate that in the south of the study area, pore water with total dissolved solids (TDS) of 2.2 g L〈sup〉−1〈/sup〉 is found up to 13.2 km offshore. Offshore pore-water salinities are more saline in the northern areas, most likely due to thinning of the offshore confining unit. The analytical solution produced freshwater-saltwater interface locations that were approximately consistent with the freshwater-saltwater stratification in two of the offshore wells, although analytical uncertainty is high. This investigation provides a leading example of offshore freshwater evaluation applying multiple techniques, demonstrating both the benefit and uncertainty of geophysical interpretation and analytical solutions of freshwater extent.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): Jagoda Crawford, Cecilia S. Azcurra, Catherine E. Hughes, John J. Gibson, Stephen D. Parkes〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉For a period of 16 months in Sydney, Australia, the variations of 〈sup〉2〈/sup〉H/〈sup〉1〈/sup〉H and 〈sup〉18〈/sup〉O/〈sup〉16〈/sup〉O in atmospheric vapour (〈em〉δ〈/em〉〈sup〉2〈/sup〉H〈sub〉A〈/sub〉 and 〈em〉δ〈/em〉〈sup〉18〈/sup〉O〈sub〉A〈/sub〉) were estimated using an evaporation pan method as well as using the isotopic precipitation-equilibrium approach. These calculations were then compared with δ〈sup〉2〈/sup〉H〈sub〉A〈/sub〉 values measured at 10 m above ground surface using a Fourier Transform Infrared Spectrometer (FTIR). As pan isotopic composition was available on a weekly time scale, the evaporation rates were measured daily, and the atmospheric variables were available hourly, the weekly time scale was used to calculate the arithmetic averages of the atmospheric variables that were used in the estimation of the pan-derived 〈em〉δ〈/em〉〈sup〉2〈/sup〉H〈sub〉A〈/sub〉.〈/p〉 〈p〉Good agreement (r = 0.7, P-value = 0.00) was found between the pan-derived and the FTIR measured 〈em〉δ〈/em〉〈sup〉2〈/sup〉H〈sub〉A〈/sub〉 for weekly intervals, although individual differences ranged from −25.0 to 20.4‰, with the absolute difference averaging 8.0‰. A sensitivity analysis showed that the determination of 〈em〉δ〈/em〉〈sup〉2〈/sup〉H〈sub〉A〈/sub〉 is most sensitive to air temperature, relative humidity and the isotopic composition of the pan water〈sub〉.〈/sub〉〈/p〉 〈p〉While the precipitation-equilibrium approach only appears to be representative of atmospheric conditions close to times of precipitation events, the pan-derived isotopic composition of atmospheric vapour was found to be closer to the FTIR averages over longer periods including intervals with no precipitation. Overall, this means that the pan method is far more effective for uninterrupted estimation of 〈em〉δ〈/em〉〈sup〉2〈/sup〉H〈sub〉A〈/sub〉 and 〈em〉δ〈/em〉〈sup〉18〈/sup〉O〈sub〉A〈/sub〉 of atmospheric water vapour, as required for water budget studies, than the precipitation-equilibrium method, and it is more cost effective and robust than continuous measurement.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): Ping Wang, L. Zeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Contaminant transport in the wetland flow is subject to various reactions. Most researches on this topic have limited to the single component contaminant, relatively little has concerned the effect of competitive reaction on the transport of coupled bicomponent contaminant. This work analytically studies the bicomponent contaminant transport in the free surface wetland flow under the combined conditions of reversible competitive transfer, irreversible degradation and bed absorption, by solving the constant-coefficient second-order linear system of parabolic type and the method of concentration moments. Up to the fourth order concentration moment in the previous work (Wang and Chen, 2017a) is applied to support the fourth order expansion of Hermite polynomials to rigorously derive the solutions with high accuracy. The results demonstrate that the masses of binary components decay at different rate, and the vertical concentration distributions of binary components are tremendously non-uniform in the asymptotic dispersion stage. Three types of reactions in addition to the hydraulic dispersion exert separate control on the concentration distributions. It suggests that the peak concentration rather than the mean should be based for strict environmental implements.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): Chao Liu, Yuqi Shan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper proposes an analytical model for predicting the longitudinal profile of depth-averaged streamwise velocities in a channel with an emergent array of rigid cylinders. The governing equation of the analytical model was derived from the momentum equation and flow continuity equation. The longitudinal transect through a flume with a vegetation patch was divided into four regions based on two length scales of flow adjustment upstream of and inside the array, and analytical solutions were proposed for the four regions. Laboratory experiments demonstrated that the array length does not influence flow adjustments near the upstream edge of the array, so the model can predict the longitudinal profile of streamwise velocity for either short or long arrays. Twenty groups of velocity data from different sources were used to verify the proposed model. The predicted velocities agreed well with the measured velocities, indicating that the model is capable of predicting the longitudinal profiles of the velocity upstream of and inside a model patch. The predicted velocity profile can be further employed to estimate regions of enhanced or diminished deposition of fine sediment or organic matter inside model patches.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): Guowangchen Liu, Lei Chen, Zhenyao Shen, Yuechen Xiao, Guoyuan Wei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The simulation and optimization of low impact development (LID) practices has been a key research topic in stormwater management. In this study, a fast and robust framework was proposed for providing the optimal design of LID practices by coupling a physically based model, the Markov chain, with the multi-objective shuffled frog leaping algorithm (MOSFLA). The proposed framework was then tested for chemical oxygen demand (COD) reduction in a typical urban catchment in China. The storm water management model (SWMM) was used to provide the flow/COD data during the baseline scenario, and the Markov chain method was then incorporated as a subset of the physically based model. Based on the results, the computational efficiency was improved by 500 times when the new framework was used, and the robustness of the optimal results increased over 50% compared to commonly used algorithms. The relative error between the SWMM and the Markov chain method was less than 5%, indicating that a satisfactory performance could be obtained using the proposed framework. This new method provides a useful tool for optimizing LID practices and green infrastructure, especially for complex urban catchments.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): Xianzhe Tang, Haoyuan Hong, Yuqin Shu, Huijun Tang, Jiufeng Li, Wei Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Urban waterlogging occurs frequently and often causes considerable damage that seriously affects human activities and the economy. Effectively assessing waterlogging susceptibility can reduce or even avoid the damage caused by such disasters. Here, a Support Vector Machine (SVM) was chosen for waterlogging susceptibility assessment due to its simplicity, objectivity, and understandability. The Particle Swarm Optimization method was used to compute parameters of the SVM. When selecting negative samples for machine learning methods, the methods of subjective selection and single random selection used in previous studies made it easy to select improper negative samples, and thus affected the classification accuracy and generalization capacity of the trained classifiers. To overcome these shortcomings, we proposed a repeatedly random sampling and verifying model to select negative samples for an SVM. As such, this study adopted the spatial framework of integrating GIS and an SVM to assess waterlogging susceptibility using the primary urban area of Guangzhou as an example. The results demonstrate that the waterlogging susceptibility map derived from the most accurate classifier (MAC) can reflect the real occurrence and spatial distribution of waterlogging. Moreover, we randomly generated 100,000 groups of samples to test the classification accuracy and generalization capacity of the MAC; the results show that in 82% of the samples, the area under the curve value of the MAC was higher than that of the randomly generated classifier. This demonstrated that the sampling and verifying model can allow the selection of an MAC with a relatively high and stable classification accuracy. The proposed sampling method can overcome the shortcomings of negative sample selection method employed in previous studies, which makes the machine learning results more accurate and reliable. Furthermore, the method requires less data, which can be helpful in developing countries where the availability of long-term intensive hydrologic monitoring data is limited.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering, Volume 125〈/p〉 〈p〉Author(s): Fu Jia, Liang Jianwen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Soil-Structure Interaction effects on the performance of Tuned-Mass-Damper are studied by a fully three-dimensional model consisting of a structure instrumented with TMD on top, and with foundation embedded in layered half-space. The influence of a variety of parameters on TMD performance, such as the structure aspect ratios and height, the foundation embedment and the soil-layer thickness, are investigated by comparing structure responses of TMD-instrumented system with un-instrumented system. The performance degradation of TMD due to ignoring SSI, is studied by comparing the efficiency of a well-tuned damper, with one which is off-tuned to the fixed-base frequency of the structure. It is shown in case studies of four buildings in California that a well-tuned damper performs better than an off-tuned one by up to 25%, although an off-tuned one may also reduce the structure responses by up to 30%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 2 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment〈/p〉 〈p〉Author(s): Weiwei Liu, Jon Atherton, Matti Mõttus, Jean-Philippe Gastellu-Etchegorry, Zbyněk Malenovský, Pasi Raumonen, Markku Åkerblom, Raisa Mäkipää, Albert Porcar-Castell〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solar-induced chlorophyll fluorescence (SIF) has been shown to be a suitable remote sensing proxy of photosynthesis at multiple scales. However, the relationship between fluorescence and photosynthesis observed at the leaf level cannot be directly applied to the interpretation of retrieved SIF due to the impact of canopy structure. We carried out a SIF modelling study for a heterogeneous forest canopy considering the effect of canopy structure in the Discrete Anisotropic Radiative Transfer (DART) model. A 3D forest simulation scene consisting of realistic trees and understory, including multi-scale clumping at branch and canopy level, was constructed from terrestrial laser scanning data using the combined model TreeQSM and FaNNI for woody structure and leaf insertion, respectively. Next, using empirical data and a realistic range of leaf-level biochemical and physiological parameters, we conducted a local sensitivity analysis to demonstrate the potential of the approach for assessing the impact of structural, biochemical and physiological factors on top of canopy (TOC) SIF. The analysis gave insight into the factors that drive the intensity and spectral properties of TOC SIF in heterogeneous boreal forest canopies. DART simulated red TOC fluorescence was found to be less affected by biochemical factors such as chlorophyll and dry matter contents or the senescent factor than far-red fluorescence. In contrast, canopy structural factors such as overstory leaf area index (LAI), leaf angle distribution and fractional cover had a substantial and comparable impact across all SIF wavelengths, with the exception of understory LAI that affected predominantly far-red fluorescence. Finally, variations in the fluorescence quantum efficiency (Fqe) of photosystem II affected all TOC SIF wavelengths. Our results also revealed that not only canopy structural factors but also understory fluorescence should be considered in the interpretation of tower, airborne and satellite SIF datasets, especially when acquired in the (near-) nadir viewing direction and for forests with open canopies. We suggest that the modelling strategy introduced in this study, coupled with the increasing availability of TLS and other 3D data sources, can be applied to resolve the interplay between physiological, biochemical and structural factors affecting SIF across ecosystems and independently of canopy complexity, paving the way for future SIF-based 3D photosynthesis models.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 231〈/p〉 〈p〉Author(s): Rafael Almar, Erwin W.J. Bergsma, Philippe Maisongrande, Luis Pedro Melo de Almeida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This article shows the capacity do derive depth using the sub metric Pleiades satellite mission (Airbus/CNES) in persistent mode, which allows acquiring a sequence of images (12 images) at a regional scale (~100 km〈sup〉2〈/sup〉). To derive depths, a spatiotemporal cross-correlation method for estimating wave velocity and inverse bathymetry is presented and applied to the 12-image sequence. A good agreement is found with in-situ bathymetry measurements obtained during the COMBI 2017 Capbreton experiment (correlation of 0.8, RMSE = 1.4 m). Depth estimate saturation is found for depths 〉35 m, mainly in a deep canyon just off the coast located in front of the entrance to Capbreton harbour. The image sequence is used to study the sensitivity of the number of images. The results show that the accuracy increases with the number of images in the sequence and with a fine resolution. Despite their noisy nature, newly available time-updated satellite bathymetries can be used to understand coastal evolution at several scales and improve risk mitigation strategies through modelling.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 231〈/p〉 〈p〉Author(s): Benjamin P. Page, Leif G. Olmanson, Deepak R. Mishra〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study demonstrates the applicability of harmonizing Sentinel-2 MultiSpectral Imager (MSI) and Landsat-8 Operational Land Imager (OLI) satellite imagery products to enable the monitoring of inland lake water clarity in the Google Earth Engine (GEE) environment. Processing steps include (1) atmospheric correction and masking of MSI and OLI imagery, and (2) generating scene-based water clarity maps in terms of Secchi depth (SD). We adopted ocean-color based atmospheric correction theory for MSI and OLI sensors modified with associated scene-specific metadata and auxiliary datasets available in GEE to generate uniform remote sensing reflectances (R〈sub〉〈em〉rs〈/em〉〈/sub〉) products over optically variable freshwater lake surfaces. MSI-R〈sub〉〈em〉rs〈/em〉〈/sub〉 products derived from the atmospheric correction were used as input predictors in a bootstrap forest to determine significant band combinations to predict water clarity. A SD model for MSI (SD〈sub〉〈em〉MSI〈/em〉〈/sub〉) was then developed using a calibration dataset consisting of log-transformed SD〈sub〉〈em〉in situ〈/em〉〈/sub〉 measurements (lnSD〈sub〉〈em〉in situ〈/em〉〈/sub〉) from 79 optically variable freshwater inland lakes collected within ±1 day of satellite overpass on 23-Aug 2017 (MAE = 0.53 m) and validated with 276 samples collected within ±1 day of a 12-Sep 2017 image (MAE = 0.66 m) across three ecoregions in Minnesota, USA. A separate SD model for MSI was also developed using similar spectral bands present on the OLI sensor (SD〈sub〉〈em〉sOLI〈/em〉〈/sub〉) where cross-sensor performance can be evaluated during coincident overpass events. SD〈sub〉〈em〉sOLI〈/em〉〈/sub〉 applied to both MSI and OLI (SD〈sub〉〈em〉OLI〈/em〉〈/sub〉) models were further validated using two coincident overpass sets of imagery on 27-Sep 2017 (〈em〉n〈/em〉 = 18) and 13-Aug 2018 (〈em〉n〈/em〉 = 43), yielding a range of error from 0.25 to 0.67 m. Potential sources of model errors and limitations are discussed. Data derived from this multi-sensor methodology is anticipated to be used by researchers, lake resource managers, and citizens to expedite the pre-processing steps so that actionable information can be retrieved for decision making.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 231〈/p〉 〈p〉Author(s): Martyna Wietecha, Łukasz Jełowicki, Krzysztof Mitelsztedt, Stanisław Miścicki, Krzysztof Stereńczak〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The primary goal of this study was to bridge the gap between hyperspectral data classifications and their practical implementation for forest management. Information on the distributions and abundances of tree species can help forest managers understand the spatial coverage of tree species and manage the species composition by establishing a specific strategy. For this purpose, classification of tree species was applied to airborne hyperspectral imagery, and a determination of selected forest stand characteristics (i.e., main tree species, species cover proportions, and species mixture patterns) was made.〈/p〉 〈p〉We selected the Milicz Forest District of southwestern Poland as our study area. Sixteen airborne hyperspectral images were acquired with the HySpex VNIR-1800 and SWIR-384 sensors on 19 August 2015. We classified four deciduous tree species (Black alder, Pedunculate oak, Silver birch, and European beech) and coniferous species using a support vector machine (SVM) classifier. To properly evaluate the classification accuracy, the level of crown visibility from above was determined during ground measurements. The obtained information was used to create a reference set integrated with the Remote Sensing data.〈/p〉 〈p〉The classification accuracy was 91%. The main tree species found in the sample plots were correctly assessed based on the coverage area for 92% of the sample plots. The species cover proportions were estimated correctly for 75–94% of the sample plots with a tolerance threshold ≤10 percentage points depending on the species considered. Similarities of the species structures shown in the sample plots between the classification map and reference field data were found by Morisita's index (0.92). Spatial mixture pattern detection was performed for 316 forest stands. The results of the developed method were found to agree to field data with 69% accuracy. This study shows that airborne hyperspectral data serve as a reliable source for the precise description of forest characteristics, such as the main tree species, tree species cover proportions and mixture patterns.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 50〈/p〉 〈p〉Author(s): Abdelkader Dairi, Tuoyuan Cheng, Fouzi Harrou, Ying Sun, TorOve Leiknes〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Wastewater treatment plants (WWTPs) are sustainable solutions to water scarcity. As initial conditions offered to WWTPs, influent conditions (ICs) affect treatment units states, ongoing processes mechanisms, and product qualities. Anomalies in ICs, often raised by abnormal events, need to be monitored and detected promptly to improve system resilience and provide smart environments. This paper proposed and verified data-driven anomaly detection approaches based on deep learning methods and clustering algorithms. Combining both the ability to capture temporal auto-correlation features among multivariate time series from recurrent neural networks (RNNs), and the function to delineate complex distributions from restricted Boltzmann machines (RBM), RNN-RBM models were employed and connected with various classifiers for anomaly detection. The effectiveness of RNN based, RBM based, RNN-RBM based, or standalone individual detectors, including expectation maximization clustering, K-means clustering, mean-shift clustering, one-class support vector machine (OCSVM), spectral clustering, and agglomerative clustering algorithms were evaluated by importing seven years ICs data from a coastal municipal WWTP where more than 150 abnormal events occurred. Results demonstrated that RNN-RBM-based OCSVM approach outperformed all other scenarios with an area under the curve value up to 0.98, which validated the superiority in feature extraction by RNN-RBM, and the robustness in multivariate nonlinear kernels by OCSVM. The model was flexible for not requiring assumptions on data distribution, and could be shared and transferred among environmental data scientists.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Coastal Engineering, Volume 152〈/p〉 〈p〉Author(s): Rik Gijsman, Jan Visscher, Torsten Schlurmann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Migration of nearshore sandbars results from nonlinear interacting hydro- and morphodynamic processes in the surf zone of wave dominated sandy shorelines. To gain new insights in the largely varying temporal effects of shoreface nourishments within these areas, the principle component analysis is applied to sixteen data sets with i) natural sandbar migration on different timescales and ii) interfering shoreface nourishments. The statistical methodology is able to separate the non-stationary effects of shoreface nourishments from the natural stationary migration of the sandbars. Depending on other long-term morphodynamic changes and nourishment interactions in the data, the duration of these interferences (the nourishment lifetimes) can be quantified. Relating these nourishment lifetimes (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉L〈/mi〉〈/mrow〉〈mrow〉〈mi〉n〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉) with respect to the bar cycle return periods (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉T〈/mi〉〈/mrow〉〈mrow〉〈mi〉r〈/mi〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉) of these areas (e.g. the relative nourishment lifetime) of twenty-one shoreface nourishments with several design parameters, and parameters of the sandbar system in which they were placed, remained inconclusive. A negative exponential fit with the bar cycle return period itself was the most significant (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈mrow〉〈msup〉〈mrow〉〈mi〉r〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉  = 0.41). Assuming a linear system of the parameters increases the predictive capability (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈mrow〉〈msup〉〈mrow〉〈mi〉r〈/mi〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉  = 0.67). The most influential parameters in this relation are the nourishment concentration (+), the nourishment depth (+), the concentration of the migrating sandbars (−) and the bar cycle return period (−), thereby indicating the prominent roles of both nourishment design and natural sandbar system in the inter-site variability of shoreface nourishment lifetimes.〈/p〉〈/div〉 〈/div〉

Description: Abstract Reliable estimation of the volume and timing of snowmelt runoff is vital for water supply and flood forecasting in snow‐dominated regions. Snowmelt is often simulated using temperature‐index (TI) models due to their applicability in data‐sparse environments. Previous research has shown that a modified‐TI model, which uses a radiation‐derived proxy temperature instead of air temperature as its surrogate for available energy, can produce more accurate snow covered area (SCA) maps than a traditional TI model. However, it is unclear whether the improved SCA maps are associated with improved snow water equivalent (SWE) estimation across the watershed or improved snowmelt‐derived streamflow simulation. This paper evaluates whether a modified‐TI model produces better streamflow estimates than a TI model when they are used within a fully‐distributed hydrologic model. It further evaluates the performance of the two models when they are calibrated using either point SWE measurements or SCA maps. The Senator Beck Basin in Colorado is used as the study site because its surface is largely bedrock, which reduces the role of infiltration and emphasizes the role of the SWE pattern on streamflow generation. Streamflow is simulated using both models for six years. The modified‐TI model produces more accurate streamflow estimates (including flow volume and peak flow rate) than the TI model, likely because the modified‐TI model better reproduces the SWE pattern across the watershed. Both models also produce better performance when calibrated with SCA maps instead of point SWE data, likely because the SCA maps better constrain the space‐time pattern of SWE.

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 51〈/p〉 〈p〉Author(s): Neng Zhu, Daokun Chong〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hyperthermal environments in public or industrial buildings impose substantial heat stress on the human body. To ensure human health in built environments, research has focused on the interactions between the heat tolerance and environments. This paper summarizes the progress in the literature concerning the evaluation and improvement of heat tolerance in three areas: environmental and physiological parameters, heat tolerance evaluation indexes, and heat acclimation (HA). This review leads to four conclusions: (1) Future indexes should give top priority to subjective perceptions to diminish individual differences; (2) machine learning techniques based on big data should be adopted to deal with complex correlations between hot environments and heat tolerance; (3) an optimal HA training regimen should be determined for workers to improve their heat tolerance and HA should be considered in the design and control strategies of indoor thermal environments for energy conservation; and (4) more field investigations should be conducted to modify laboratory-based findings. This review provides a comprehensive understanding of built environments and health and guidelines for future research.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 51〈/p〉 〈p〉Author(s): Sophie A. Nitoslawski, Nadine J. Galle, Cecil Konijnendijk van den Bosc, James W.N. Steenberg〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Smart cities are increasingly part of urban sustainability discourses. There is a growing interest in understanding how citizen engagement, connected technology, and data analytics can support sustainable development. Evidence has also repeatedly shown that green infrastructure such as urban forests address diverse urban challenges and are critical components of urban sustainability and resilience. Nevertheless, it is unclear whether green space and urban forest management are gaining significant traction in smart city planning. It is thus timely to consider whether and to what extent urban forests and other green spaces can be effectively integrated into smart city planning, to maximize green benefits for all city dwellers.〈/p〉 〈p〉We address this gap by exploring current and emerging smart city trends and technologies, and highlight practical applications for urban forest and green space management. Current “smart urban forest” projects reveal a focus on novel monitoring techniques using sensors and Internet of Things (IoT) technologies, as well as open data and citizen engagement, particularly through the use of mobile devices, applications (“apps”), and open-source mapping platforms. We propose a definition and promising approach to “smart urban forest management”, emphasizing both the potential of digital infrastructure to enhance forest benefits and the facilitation of citizen stewardship and empowerment in green space planning. Cities are getting faster and smarter – can (and should) the trees, and their managers, do the same?〈/p〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 51〈/p〉 〈p〉Author(s): Jun Bao, Yu Wang, Xinjie Xu, Xiaoyi Niu, Jinxiang Liu, Lanlan Qiu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The development of big data leads to the increasing heat dissipation of data center chips. As an efficient pattern to remove high heat flux, spray cooling has huge potential for data center cooling. Spray cooling system was established combined with PIV (Particle Image Velocimetry) system. The PIV was used to measure the flow pattern distribution of different nozzle sprays, while the surface heat flux and heat transfer coefficient were obtained by the thermocouples. The results show that as the spray diameter decreases, the outlet pressure and outlet velocity of the droplet increase, and the spray cone angle increases, causing only a small amount of droplets actually participate in the heat exchange, resulting in a higher velocity and a smaller heat transfer coefficient. It is also inferred that better uniformity of droplets velocity is beneficial for the heat transfer performance. Moreover, to further enhance the heat transfer performance, nano-alumina solution with five different fractions was applied to the experimental system. It is found that the heat transfer coefficient of the surface reaches an optimum value with a maximum velocity obtained by the PIV when the mass fraction of the solution is 0.08%.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 51〈/p〉 〈p〉Author(s): Peleg Kremer, Annegret Haase, Dagmar Haase〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, we introduce the special issue “The future of urban sustainability: Smart, efficient, green or just?” the special issue aims to explore the relationships, conflicts and connections between different approaches to urban sustainability and begin to build a shared understanding of the roles, synergies and tradeoffs between them. Papers in this special issue emphasize the multidimensionality of urban sustainability and its integration of social, ecological, economic, and technological systems.〈/p〉〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Sustainable Cities and Society, Volume 51〈/p〉 〈p〉Author(s): Sabah Abdul-Wahab, Ziyad Alsubhi〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Despite the small quantities of hydrogen fluoride (HF) that are emitted from aluminum smelters compared with the other gaseous emissions, HF is one of the most dangerous gases to be considered when studying the environmental impact of these smelters. Therefore, modeling HF dispersion is essentially important to make sure that concentrations do not exceed threshold limit, especially for buildings, which are located close to the emission source. The objective of the current study was to examine the dispersion of atmospheric HF emitted from an aluminum smelter located in Oman. The results of the study indicated that the concentrations were found to be well below the allowable concentrations. Results in winter showed that the highest hourly HF concentration (0.104 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.svg"〉〈msup〉〈mrow〉〈mtext〉 〈/mtext〉〈mtext〉μ〈/mtext〉〈mtext〉g〈/mtext〉〈mo〉/〈/mo〉〈mtext〉m〈/mtext〉〈/mrow〉〈mn〉3〈/mn〉〈/msup〉〈mo stretchy="false"〉)〈/mo〉〈/math〉 was occurred at 18:00 h local standard time and was found to be at a location −9.5 km west and 2.5 km north of the plant. Conversely, the simulation in summer indicated that the highest hourly HF concentration (0.374 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg"〉〈msup〉〈mrow〉〈mtext〉μ〈/mtext〉〈mtext〉g〈/mtext〉〈mo〉/〈/mo〉〈mtext〉m〈/mtext〉〈/mrow〉〈mn〉3〈/mn〉〈/msup〉〈mo stretchy="false"〉)〈/mo〉〈/math〉 was obtained at 22:00 h and was found to be at a location -8.5 km west and 3.5 km north of the plant. The results of the study will have significant importance to the residents, stakeholders, and related permitting authorities in the area.〈/p〉〈/div〉

Description: 〈p〉Publication date: Available online 29 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part D: Transport and Environment〈/p〉 〈p〉Author(s): Zhao Zhang, Brian Wolshon, Pamela Murray-Tuite〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Evacuations, a critical and widely used emergency response action, vary widely in terms of their scale, scope, urgency and level of organization. While they differ from event to event, history shows that there are a small set of variables, inherent to all evacuations, that largely govern their effectiveness. In this paper, these fundamental variables are described from a theoretical perspective to illustrate how factors of evacuation demand and supply affect clearance time and how they can also be used to relate evacuation planning to concepts of risk, resiliency, and resource allocation. This work provides a basis for a general theory of evacuation processes that can be used it to conceptualize relationships like cost-benefit tradeoffs in evacuation management to improve long-range evacuation planning through a better understanding of the investment and allocation of resources.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part B: Methodological, Volume 128〈/p〉 〈p〉Author(s): Xiaotian Wang, Xin Wang〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Reservation-based parking systems have the merit of eliminating vehicle cruising for parking. While many long-period (e.g., daily) parking reservation services are already in use, short-period (e.g., hourly) parking reservation remains a huge challenge due to the high uncertainty of customer arrivals and departures. To mitigate the service failure caused by random late departures of customers, we propose a new flexible reservation mechanism in which the reservation is no longer restricted to a specific location at a specific time, but tolerates predetermined spatiotemporal flexibility instead. With a pricing instrument designed for such parking flexibility, customers can coordinate to significantly reduce the reservation failure rate, resulting in an optimal system equilibrium benefiting the entire society. Due to the complex nature of this system, a continuum approximation framework is used to provide tractable analysis for a large-scale urban parking system. We can successfully provide accurate system management decision support with a bounded optimality gap and analytical insights.〈/p〉〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part B: Methodological, Volume 128〈/p〉 〈p〉Author(s): Li Li, Saif Eddin Jabari〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Decentralized intersection control techniques have received recent attention in the literature as means to overcome scalability issues associated with network-wide intersection control. Chief among these techniques are backpressure (BP) control algorithms, which were originally developed of for large wireless networks. In addition to being light-weight computationally, they come with guarantees of performance at the network level, specifically in terms of network-wide stability. The dynamics in backpressure control are represented using networks of point queues and this also applies to all of the applications to traffic control. As such, BP in traffic fail to capture the spatial distribution of vehicles along the intersection links and, consequently, spill-back dynamics.〈/p〉 〈p〉This paper derives a position weighted backpressure (PWBP) control policy for network traffic applying continuum modeling principles of traffic dynamics and thus capture the spatial distribution of vehicles along network roads and spill-back dynamics. PWBP inherits the computational advantages of traditional BP. To prove stability of PWBP, (i) a Lyapunov functional that captures the spatial distribution of vehicles is developed; (ii) the capacity region of the network is formally defined in the context of macroscopic network traffic; and (iii) it is proved, when exogenous arrival rates are within the capacity region, that PWBP control is network stabilizing. We conduct comparisons against a real-world adaptive control implementation for an isolated intersection. Comparisons are also performed against other BP approaches in addition to optimized fixed timing control at the network level. These experiments demonstrate the superiority of PWBP over the other control policies in terms of capacity region, network-wide delay, congestion propagation speed, recoverability from heavy congestion (outside of the capacity region), and response to incidents.〈/p〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part D: Transport and Environment, Volume 75〈/p〉 〈p〉Author(s): Kate Hosford, Meghan Winters, Daniel Fuller〈/p〉

Description: Abstract This study aims at proposing novel approaches for integrating qualitative flow observations in a lumped hydrologic routing model and assessing their usefulness for improving flood estimation. Routing is based on a three‐parameter Muskingum model used to propagate streamflow in five different rivers in the United States. Qualitative flow observations, synthetically generated from observed flow, are converted into fuzzy observations using flow characteristic for defining fuzzy classes. A model states updating method and a model output correction technique are implemented. An innovative application of Interacting Multiple Models, which use was previously demonstrated on tracking in ballistic missile applications, is proposed as state updating method, together with the traditional Kalman filter. The output corrector approach is based on the fuzzy error corrector, which was previously used for robots navigation. This study demonstrates the usefulness of integrating qualitative flow observations for improving flood estimation. In particular, state updating methods outperform the output correction approach in terms of average improvement of model performances, while the latter is found to be less sensitive to biased observations and to the definition of fuzzy sets used to represent qualitative observations.

Description: Abstract The Sustainable Development Goals (SDGs) of the United Nations Agenda 2030 represent an ambitious blueprint to reduce inequalities globally and achieve a sustainable future for all mankind. Meeting the SDGs for water requires an integrated approach to managing and allocating water resources, by involving all actors and stakeholders, and considering how water resources link different sectors of society. To date, water management practice is dominated by technocratic, scenario‐based approaches that may work well in the short‐term, but can result in unintended consequences in the long‐term due to limited accounting of dynamic feedbacks between the natural, technical and social dimensions of human‐water systems. The discipline of socio‐hydrology has an important role to play in informing policy by developing a generalizable understanding of phenomena that arise from interactions between water and human systems. To explain these phenomena, socio‐hydrology must address several scientific challenges to strengthen the field and broaden its scope. These include engagement with social scientists to accommodate social heterogeneity, power relations, trust, cultural beliefs, and cognitive biases, which strongly influence the way in which people alter, and adapt to, changing hydrological regimes. It also requires development of new methods to formulate and test alternative hypotheses for the explanation of emergent phenomena generated by feedbacks between water and society. Advancing socio‐hydrology in these ways therefore represents a major contribution towards meeting the targets set by the SDGs, the societal grand challenge of our time.

Description: Abstract Field data of topography, water levels, and peat hydraulic conductivity collected over a 28‐year period have revealed the impacts of marginal drainage on uncut raised bog ecohydrology and its peat properties. Drainage of the regional groundwater body has induced changes in the hydraulic properties of deep peat, with peat compression decreasing hydraulic conductivity and storativity while simultaneously introducing localized secondary porosity and effective storage. Where peat has increased in hydraulic conductivity, there is a corresponding decline in vertical hydraulic gradients and significant localized increases in recharge to the underlying substrate. Repeated topographic surveys show intense localized areas of peat consolidation (〉5%) where it is underlain by highly permeable (〉10 m/day) glacial till deposits. More widely, continued subsidence (4–6 mm/year) of the bog surface has been measured over 900 m from the bog margin, resulting in the progressive loss of approximately 40% of actively growing raised bog since 1991. This loss has thus been shown to be attributable to changes in the underlying groundwater head due to deep‐cut drainage, rather than near‐surface peatland drainage. However, although reinstating regional hydrostatic pressures in order to restore this ombrotrophic peatland may control the rapid drainage through preferential flow pathways, this may not eliminate the ecological impacts resulting from changed surface morphology arising from subsidence. Hence, this longitudinal study provides new insights into the role that aquifer systems and groundwater bodies play in maintaining hydrogeological processes in ombrotrophic peatland systems, while highlighting the difficulty in ecological restoration where regional groundwater dependencies are significant.

Description: Abstract The mismatch between water demand and water availability in many megacities poses vexing water management challenges. Managers are forced to take remedial efforts to address these challenges, often with a heavy focus on infrastructure solutions such as building reservoirs or interbasin transfers to meet demand, which may in fact exacerbate the problem through unintended consequences that arise from neglect of social, economic, and environmental factors. Such a situation awaits Beijing, China, which faces major water management challenges in spite of the addition of a large interbasin transfer to meet increasing demand. In this study, a sociohydrologic model is developed for investigating Beijing's future water sustainability from a holistic and dynamic perspective. Using the model, we first explore the sociohydrologic mechanisms that contributed to Beijing's worsening water situation during 1988–2014. We then use the model to assess possible future impacts of the South to North Water Diversion Project on Beijing's water supply prospects for the 2015–2035 period. Alternative futures are explored by combining three different sustainable management strategies. The model results show that the source of Beijing's dominant water pressure experienced a transformation from productive to domestic water use over the last 30 years. They also indicate that the transfer water via South to North Water Diversion Project cannot fundamentally reverse Beijing's water shortage in the long term and that demand‐oriented management measures will be required for alleviating the city's water stress. These findings provide guidance not only for Beijing's water management but also for other less developed cities around the world.

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 577〈/p〉 〈p〉Author(s): Changkun Ma, Xiangdong Li, Yi Luo, Mingan Shao, Xiaoxu Jia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Interception loss can remove a significant portion of rainwater from forested ecosystems. Therefore, the quantification and modelling of interception loss are of significant importance if human and ecosystem water demands are to be balanced under a future changing climate. This is particularly true for semi-arid/arid regions, where afforestation has become an important ecological restoration measure to tackle desertification, poverty and climate change. However, quantification and modelling of interception loss of plantations in these regions have rarely been reported. In the present study, rainfall interception loss was quantified and modelled over a one-year period (January-December 2016) for a deciduous broad-leafed 〈em〉R. pseudoacacia〈/em〉 plantation and an evergreen needle-leaf 〈em〉P. tabuliformis〈/em〉 plantation (common afforestation tree species) situated in the semi-arid Loess Plateau of China. The stand age, density, canopy cover and leaf area index of 〈em〉R. pseudoacacia〈/em〉 during the study period were 15 years, 2000 tree ha〈sup〉−1〈/sup〉, 0.48 and 1.41 m〈sup〉2〈/sup〉 m〈sup〉−2〈/sup〉, respectively. The corresponding values for 〈em〉Pinus tabuliformis〈/em〉 were 17 years, 1200 tree ha〈sup〉−1〈/sup〉, 0.62 and 2.53 m〈sup〉2〈/sup〉 m〈sup〉−2〈/sup〉. The measured throughfall, stemflow and derived estimates of interception loss for 〈em〉R. pseudoacacia〈/em〉 were 81.1%, 1.3% and 17.6%, respectively. The corresponding values for 〈em〉P. tabuliformis〈/em〉 were 75.4%, 0.7% and 23.9%. Given that the weather conditions experienced by the two forest stands were similar, the observed higher interception loss for 〈em〉P. tabuliformis〈/em〉 can be explained by the higher canopy storage capacity and wet canopy evaporation rate of this species. The revised Gash analytical model of rainfall interception was well calibrated and validated against field measurements and was able to simulate the cumulative interception loss at two forest stands accurately, and it also effectively captured the seasonal variation (leafed growing and leafless dormant seasons), provided that the optimized wet-canopy evaporation rates were used. The revised model was highly sensitive to the canopy storage capacity and changes in the ratio of mean wet canopy evaporation to mean rainfall intensity and less sensitive to canopy cover, but it was found to be fairly insensitive to the trunk storage capacity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 577〈/p〉 〈p〉Author(s): Yonghuai Yang, Biyang Wen, Caijun Wang, Yidong Hou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Non-contact flow measurement method plays an increasingly important role in river discharge measurement. However, most channel cross-section velocity distribution models proposed by researchers have certain limitations in application, underwater velocities are always necessary when applied in narrow channels, which makes it challenging to calculate natural river discharge using water-surface velocities measured by remote sensing instruments. This letter takes water-surface velocities detected by UHF radar as boundary conditions and a new velocity distribution model is derived based on the Reynolds-Averaged Navier-Stokes (RANS) equations. UHF radar measures surface velocities of the cross-section, and velocities on the river bed of the cross-section are considered to be 0. The RANS equations are simplified to be a two-dimensional Poisson equation and the cross-section velocity distribution is solved by using the closed boundary conditions. Some field experiments were conducted in the Hanjiang River at Xiantao, Hubei, China in September 2017 and April–July 2018, the processing results of which show that the proposed model is superior to the power law and the log law models, especially near the side wall (narrow channel region). River discharges calculated by this method are highly consistent with those provided by Hubei Xiantao hydrologic station, which verifies the reliability of the model and the feasibility of using UHF radar to measure natural river discharge continuously and automatically.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 578〈/p〉 〈p〉Author(s): Yunliang Li, Qi Zhang, Xinggen Liu, Zhiqiang Tan, Jing Yao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Seasonal lakes that exist in floodplain settings have significant effects on hydrological and ecological processes and are highly susceptible to various changes; however, they are rarely investigated, mainly because of the large extent and remoteness of floodplains. This study uses physically based hydrodynamic modeling in combination with a bathymetry adjustment approach to investigate the coupling effects of 77 seasonal lakes (defined as the seasonal lake group) on hydrological behaviors within the Poyang Lake-floodplain system (China) from a systemic perspective. Elucidation of the role of seasonal lake groups could benefit from hydrodynamic modeling, which enables complex lake-floodplain simulations and comparison analyses of natural (original bathymetry) and hypothetical conditions (adjusted bathymetry). In the present study, the simulation results showed that the temporal influences of the seasonal lake group on water levels, lake outflows, and inundation dynamics were greater during dry seasons than wet seasons for both the dry (2006) and wet years (2010). The spatial effects of the seasonal lake group on the hydrology of the lake’s floodplains were stronger than those of the main lake for both hydrological years. The findings demonstrate that the seasonal lakes are likely to have very limited effects on the main lake and the associated flood levels. On average, the role of the seasonal lake group during the dry seasons was around several times stronger than that during flood seasons in terms of the magnitudes of hydrological responses. Additionally, it is expected that the seasonal lake group may exert an important role in influencing the surface hydrological connectivity and associated dry-wet hydrological shift across lake-floodplains, indicating a dominant role of the floodplain bathymetry changes. Overall, the results of this study will support management and planning of Poyang Lake and other similar floodplain regions with numerous small, shallow, and seasonal lakes by providing more reliable information regarding bathymetry changes, water management and lake-floodplain interactions to decision-makers for improved floodplain protection strategy.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022169419307826-ga1.jpg" width="285" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 578〈/p〉 〈p〉Author(s): Kim Vercruysse, David A. Dawson, Vassilis Glenis, Robert Bertsch, Nigel Wright, Chris Kilsby〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Integrated flood management is essential in urban planning to align flood protection and mitigation with the complex social and physical infrastructure in cities, and involves managing surface water by retaining and transferring it along its pathway across multiple infrastructure systems. However, despite many potential flood management solutions (natural and engineered), spatial prioritization to implement these solutions from a catchment perspective remains difficult. A transferable, source-to-impact flood analysis is developed to identify locations with high surface flooding (impact) and locations contributing to this flooding (source), to define spatial prioritization criteria for flood management intervention. The analysis was applied to Newcastle-upon-Tyne (UK) and combined a spatial rainfall cell dependency analysis with the hydrodynamic flood model CityCAT. Locations within the study area were then classified based on four priority criteria: contribution to (i) total flood extent; (ii) maximum flood depths; (iii) flooded green spaces and roads; and (iv) likelihood of flood exposure. The results illustrate the importance of considering the catchment holistically and identify hydrological linkages between flood source and impact areas, and the corresponding impact on (and interaction with) different infrastructure systems. Different criteria lead to different spatial prioritization information, which stresses the importance of combining criteria that address the specific needs and targets of the desired flood management strategy (e.g. Blue-Green infrastructure). The concept offers a basis for developing a systematic, high-level approach to inform catchment-scale prioritization for flood management intervention, which can be applied prior to developing flood alleviation schemes. In doing so, the approach will help identify opportunities to combine multiple water management solutions and allocate resources more efficiently.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 577〈/p〉 〈p〉Author(s): Ping-Cheng Hsieh, Ding-You Wang, Ming-Chang Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Urban areas are often covered by materials with smooth ground surface and poor water permeability, which may cause problems such as increasing flow velocity and discharge.〈/p〉 〈p〉This study employed the diffusion wave equation to investigate the variation of overland flow, and analytical solutions were obtained by the generalized integral transformation technique. Examining previous research, we found when the coefficients in the diffusion wave equation were treated as constants, the simulated results would be mass non-conservative. This study corrected the coefficients which makes the flow meet the mass conservation law to improve the simulation results. An alternative solution to the overland flow considering time-varying rainfall and infiltration were proposed and the results were well compared with previous numerical solutions and experimental data.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 577〈/p〉 〈p〉Author(s): Bahram Choubin, Moslem Borji, Amir Mosavi, Farzaneh Sajedi-Hosseini, Vijay P. Singh, Shahaboddin Shamshirband〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Snow avalanches are among the most destructive natural hazards threatening human life, ecosystems, built structures, and landscapes in mountainous regions. The complexity of snow avalanche modelling has been discussed in many studies, but its modelling is not well-documented. Snow avalanche modeling in this study was done using three main categories of data, including avalanche occurrence locations, meteorological factors, and terrain characteristics. Two machine learning models, namely support vector machine (SVM) and multivariate discriminant analysis (MDA), were employed. A ratio of 70 to 30 of data was considered for calibrating and validating the models. Results indicated that both models had an excellent performance in snow avalanche modeling (area under curve, AUC 〉 90), although hits and misses analysis demonstrated the superior performance of MDA. Sensitivity analysis indicated that the topographic position index, slope, precipitation, and topographic wetness index were the most effective variables for modeling. A snow avalanche map indicated that the high snow avalanche hazard zone was mostly near the streams and was matched with hillsides around the water pathways. Findings of study can be helpful for land use planning, to control snow avalanche paths, and to prevent the probable hazards induced by it, and it can be a good reference for future studies on modeling snow avalanche hazards.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 577〈/p〉 〈p〉Author(s): Xu Li, Zhang Wen, Hongbin Zhan, Qi Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Single-well push-pull (SWPP) test is one of the most important ways to estimate flow and transport parameters, e.g. porosity, dispersivity, regional groundwater flow velocity. Usually the wellbore is surrounded by a finite-thickness skin, such as a gravel pack. The positive skin has a smaller hydraulic conductivity than the aquifer formation zone, and the negative skin has a greater one. In this study, a numerical model of a SWPP test considering skin effects was established using the finite-element COMSOL Multiphysics program to estimate aquifer parameters. Several important results were obtained. Firstly, regional groundwater velocity affects the types of breakthrough curves (BTCs) through changing the flow pattern. Secondly, a positive (or negative) skin leads to a slower (or faster) tracer transport process, and a smaller ratio between the hydraulic conductivity of the skin and that of the aquifer formation zone results in greater solute plume retardation in the skin zone. Thirdly, a larger thickness of the positive skin leads to a higher tracer concentration around the well, and the opposite is true if the skin is negative. Besides, the model of Leap and Kaplan (1988) underestimates the regional groundwater velocity for the second type of BTCs, and a larger longitudinal dispersivity can lead to a greater error, where the second type of BTCs has a rising limb at early stage followed by a falling limb at late stage. The general conclusion is that the estimations of groundwater velocity from SWPP tests are also affected by skin effects.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 6 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology〈/p〉 〈p〉Author(s): Pengcheng Qin, Hongmei Xu, Min Liu, Liangmin Du, Chan Xiao, Lüliu Liu, Brian Tarroja〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Climate change is expected to alter regional hydrological regimes, affecting the operation and performance of reservoirs and hydropower facilities. This study examines the impacts of climate change on the performance of the Three Gorges Reservoir (TGR) by means of a detailed daily reservoir regulation and hydropower model, linked to a physically-based hydrological model, and driven by an ensemble of five General Circulation Models (GCMs) under three Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5). As precipitation in the basin is expected to increase, the projected mean annual inflow and hydropower generation of the TGR will increase by 3.3-5.6% and 0.9-2.3% in 2040-2065, 7.9%-15.2% and 5.2-8.1% in 2080-2099 respectively. These increases are only statistically significant for 2080-2099 and are seasonally concentrated in the spring before the flood season and the early autumn during the end of the flood season. However, the inter-annual variation of power generation will increase strongly in the dry season. The reservoir performance is highly sensitive to the changes in the seasonal distribution and extremes of streamflow. Increases in streamflow that occur in the flood season cause significant increases in the amount of spilled water and advance the time when the reservoir reaches the normal storage level. Additionally, increases in both the inter-annual variation of inflow and the intensity of inflow shortages during extreme drought years in the impounding stage drive decreases in the fully filled rate and average water storage level in the dry season. The utilization rate of water resources under projected extreme streamflow is expected to decrease, reshaping the response of power generation to climate change into a non-linear pattern where increases in streamflow do not proportionally translate to increases in power generation. These findings highlight the complexity of hydropower management and production under future climate change scenarios, motivating the need for introducing detailed regulating models for impact assessment studies and adaptive adjustment of the reservoir management to combat climate change.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): Mohamed Sultan, Neil C. Sturchio, Saleh Alsefry, Mustafa K. Emil, Mohamed Ahmed, Karem Abdelmohsen, Mazen M. AbuAbdullah, Eugene Yan, Himanshu Save, Talal Alharbi, Abdullah Othman, Kyle Chouinard〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An integrated approach was developed to assess the sustainability, origin, age, evolution, and groundwater potential of large fossil aquifers using the Mega Aquifer System (MAS) (area: 2 × 10〈sup〉6〈/sup〉 km〈sup〉2〈/sup〉) in the Arabian Peninsula as a test site. A two-step exercise was adopted, the sustainability of the MAS was first investigated through the analysis of GRACE data and land surface model (LSM) outputs. Then, integrated geochemical, remote sensing, and field studies were conducted to address the age, origin, hydrogeological setting, and evolution of the southern sections of the MAS (Rub Al Khali Aquifer System (RAKAS)), the area identified from the analysis of GRACE and LSMs as being the most suited for sustainable development. Analysis of GRACE and LSMs revealed: (1) the MAS central and northern sections are experiencing high groundwater extraction (6.6 km〈sup〉3〈/sup〉/yr) and depletion rates (−2.8 ± 0.8 km〈sup〉3〈/sup〉/yr) with minimum balancing potential through aquifer capture processes, yet sustainability could be achieved by reducing annual extraction by 2.8 km〈sup〉3〈/sup〉, and (2) the MAS southern sections (Rub Al Khali Aquifer System (RAKAS)) are experiencing low groundwater depletion rates (eastern RAKAS: −1.8 ± 1.4 mm/yr) to steady-state conditions (western RAKAS: −0.73 ± 1.4 mm/yr). Geochemical, remote sensing, and field investigations over the RAKAS revealed: (1) the presence of west to east trending drainage networks and large-scale groundwater flow systems consistent with a meteoric source (precipitation over Red Sea Hills); (2) increasing 〈sup〉36〈/sup〉Cl model ages along groundwater flow directions (up to 970,000 years), indicating aquifer recharge in wet Pleistocene periods; (3) progressive depletion in the O and H stable isotopic compositions of aquifers with increasing distance from the Red Sea Hills basement outcrops, indicating modest recharge during prevailing dry conditions; and (4) the presence of relatively fresh (TDS: 800–2800 mg/L) and non-radioactive (〈sup〉226〈/sup〉Ra + 〈sup〉228〈/sup〉Ra 〈 0.185 Bq/kg) water in western RAKAS. Findings suggest that sustainable agricultural development is achievable at current extraction rates in western RAKAS and provide a replicable and cost-effective model.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 577〈/p〉 〈p〉Author(s): Hai Zhou, Wenzhi Zhao, Zhibin He, Jialiang Yan, Gefei Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mongolian pine (〈em〉Pinus sylvestris var. mongolica〈/em〉) has been widely used in vegetation restoration and for windbreaks in sandy regions of northern China where water is the principal factor limiting tree survival and growth. An understanding of water use in Mongolian pine plantations is critical for effective vegetation restoration. To determine water sources in a Mongolian pine plantation, we investigated the stable isotopic ratios of 〈em〉δ〈/em〉〈sup〉18〈/sup〉O and 〈em〉δ〈/em〉D in precipitation, groundwater, in soil water in different soil layers, and in tree xylem at different tree ages along a precipitation gradient and in different micro-landforms. The results indicated that the main water sources for Mongolian pine were precipitation-derived shallow soil water in semi-humid regions and that the contribution proportion decreased with an increase in tree age. With reduced precipitation in semi-arid and arid regions, contribution of deep soil water to Mongolian pine water use gradually increased, and differences in soil water contribution among trees due to tree age also significantly increased. Water use patterns in trees planted in different micro-landforms (e.g. sand dune crest or inter-dune lowland) became more distinct as precipitation gradually decreased across humid to semiarid and arid regions. Moreover, Mongolian pine, including 15-, 20-, 25-, and 45-year-old trees, similar height and DBH without groundwater in semi-arid climate (in Ejin Horo banner), while trees planted in extremely arid climate (Linze) relied on irrigation for survival despite abundant and available groundwater at that study site. These results indicated that groundwater may be beyond reach to be a main water source for Mongolian pine trees. Soil water conditions determined the survival and sustainable growth of planted trees, especially at depths less than 1 m where soil layers were recharged mainly by precipitation. Although Mongolian pine exhibits strong ecological adaptability, a trait that makes it ideally-suited for controlling desertification in sandy regions of northern China, water stress, crown dieback, or even tree mortality are likely to occur under conditions of extremely low precipitation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 577〈/p〉 〈p〉Author(s): Jungho Kim, Heechan Han, Lynn E. Johnson, Sanghun Lim, Rob Cifelli〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study introduces a novel hydrological assessment tool (HAT) based on hybrid machine learning (HML) framework. The HML framework combines an unsupervised clustering technique and a supervised classification technique, to determine reasonable performance ratings (unsatisfactory, satisfactory, good, and very good) and build a practical assessment tool. Hydrologically significant error indices are used to cluster the performance rating groups and train the HAT. The HAT was applied to the National Water Model (NWM), which is operated in real time for the continental United States (CONUS). For establishing, training, and validating the HAT, data from October 2013 to February 2017 were used, and a performance assessment was conducted on the NWM in the San Francisco Bay Area. As a result, the HAT determined the performance ratings that were reliable in terms of the statistics and hydrograph. It was confirmed that the HAT could perform an accurate hydrograph assessment as the concordance rate of the performance ratings was 98%. The NWM was evaluated against 57 USGS streamflow gauges using the HAT and was found to perform with 46% on average, good and very good ratings. The HML framework, an integral part of the HAT, is expected to be useful not only in hydrological analysis but also across all geophysical fields that deal with physical processes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 576〈/p〉 〈p〉Author(s): J. Leandro, A. Gander, M.N.A. Beg, P. Bhola, I. Konnerth, W. Willems, R. Carvalho, M. Disse〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉River discharges flood forecasting is a complex task with multiple sources of uncertainty. Bayesian methods can incorporate multiple types of uncertainties by inferring the probability density function of ensemble forecasts based on past events. However, such methods lead to forecasts with large uncertainty bands. In order to reduce the uncertainty in the forecasts, we focus solely on the prediction of the upper and lower range of the uncertainty bands. Therefore, we develop three forecast methods in which we search for the indexes of the upper and lower forecast members of an ensemble (termed best-pairs), which provide the highest predictive skill. The results show for four distinct hindcasts of historical events in a case study in Bavaria (Germany) that the new methods have a higher predictive skill of the observations than probabilistic methods, at least for the first 4 out of 12 h’ forecasts. Moreover, the new methods are computational efficient because they considerably reduce the number of members of the ensembles required to produce a flood discharge forecast with high predictive skill.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Conceptual representation of the probabilistic forecast (PF) (first two) and upper and lower forecast (ULF) (last three) methods: a) Ensemble, b) Relative error method, c) Discharge intervals, d) Rising and receding, and e) Slope intervals.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022169419305992-ga1.jpg" width="239" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 2 July 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology〈/p〉 〈p〉Author(s): Stephen Tuozzolo, Theodore Langhorst, Renato Prata de Moraes Frasson, Tamlin Pavelsky, Michael Durand〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Surface Water and Ocean Topography Mission (SWOT) will generate global, spatially continuous maps of water surface elevation and extent for large inland water bodies when it launches in 2021. We present an analysis of water surface elevation, width, and bathymetry timeseries data from a medium-sized (average annual discharge 14 m〈sup〉3〈/sup〉/s) river to explore Manning’s equation, an empirical open channel flow equation, in the context of SWOT discharge algorithms. While this equation is in theory inapplicable to natural channels due to the non-uniform and spatially heterogeneous nature of river systems, we explored approaches to adapt it to this context using reach-averaged variables. At twenty sites along a 6.5 km stretch of the Olentangy River in Ohio, USA, we collected automated and manual measurements of water surface elevation and river width, undertook a full bathymetric survey of the study area, and built a hydraulic model. The stretch of river was divided into five reaches, and hydraulic variables were reach-averaged. Using these variables, we used a modified form of Manning’s equation to compute a reach-averaged roughness coefficient. Reach-averaged roughness coefficients varied nonlinearly with discharge and were 2-10 times larger at low flow than at high flow in the in-situ data, ranging from 0.06 to 0.61 in one of the study reaches. These results were compared with the output of an unsteady flow simulation using a calibrated 1-D hydraulic model which was run with constant roughness coefficients at each cross section. When reach-averaged data was used, model-derived roughness coefficient also varied by more than an order of magnitude, with a range of 0.02 to 0.82 for one reach. For both in-situ and model-derived datasets, using a two-parameter roughness coefficient which scaled with a power law on either discharge or stage reduced discharge estimation error, with error for one reach dropping from 81 % to 8 % relative root-mean square error (rRMSE) in the in-situ data and 58 % to 8 % nRMSE in the modeled data. These results imply that spatial averaging of hydraulic variables leads to large variations in reach averaged Manning’s 〈em〉n〈/em〉, which we term the reach’s “effective resistance”, and suggest that this variability can be accounted for with a simple parameterization in estimates of discharge that use spatially averaged data.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Hydrology, Volume 577〈/p〉 〈p〉Author(s): Lisa D. Olsen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The author read with much interest the publication by Mize et al. (2018) on the decrease in suspended-sediment concentrations and loads in the lower Mississippi and Atchafalaya Rivers between 1980 and 2015. Researchers interested in sediment dynamics in the lower Mississippi and Atchafalaya Rivers also should be aware that sediment data previously reported for the lower Mississippi-Atchafalaya River Basin by the U.S. Geological Survey (USGS) and U.S. Army Corps of Engineers (USACE) were affected by a systematic error in the fines fraction (particle sizes less than 0.063 millimeter) of the suspended-sediment concentration. This error affected results reported from October 1973 through February 2015 for two sites on the main stem of the Mississippi River, three sites on the Atchafalaya River, one site on the Old River Outflow Channel, and one site on the Red River. The USGS and USACE identified the error and have revised the results for samples collected from October 1989 through February 2015, as reported by Norton et al. (2019a) and Norton et al. (2019b). The significant conclusions of Mize et al. (2018) and sediment loads modeled using the Weighted Regressions on Time, Discharge, and Season (WRTDS) method were unaffected by the systematic error because the models used data from unaffected sites; however, the background information provided in tables 1 and 2 of Mize et al. (2018) included references to several previous studies that contained results affected by the error. This comment paper identifies which references in Mize et al. (2018) were affected by the error and alerts readers to implications of the data revision.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Remote Sensing of Environment, Volume 232〈/p〉 〈p〉Author(s): Yong Ge, Shan Hu, Zhoupeng Ren, Yuanxin Jia, Jianghao Wang, Mengxiao Liu, Die Zhang, Weiheng Zhao, Yaowen Luo, Yangyang Fu, Hexiang Bai, Yuehong Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉China aims to end absolute poverty by 2020. In pursuit of this goal, a series of poverty reduction policies and measures have been proposed. As a vital element of poverty reduction, land use in China's poverty-stricken areas also undergone great changes accordingly. However, the land use change patterns in these areas are not well understood. It's necessary to analyze the spatial-temporal land use change patterns to provide data that support poverty alleviation programs. In this study, we proposed a framework for mapping annual land use changes in China's poverty-stricken areas from 2013 to 2018. The Landsat 8 surface reflectance datasets from 2013 to 2018 (available on Google Earth Engine) were utilized to detect the changes in arable land, built-up land, water, vegetation, and un-used land. The land use transition matrix was computed to describe characteristics of the transition, and a Bayesian hierarchical model was employed to investigate the spatial-temporal land use change patterns. Our results demonstrated that the arable land continuously decreased over the study period, while built-up land and vegetation gradually expanded. The primary land use transition occurred between the arable land and vegetation. The local trends of each county indicated obvious regional differences of land use change. Moreover, significant differences existed between deep poverty-stricken counties and normal poverty-stricken counties on arable land and built-up land change, indicating that more intense human construction activities in normal poverty-stricken areas. The annual land use mapping results generated for poverty-stricken areas, along with further analysis of overall temporal change and local change trends, could provide a better understanding of land use changes and regional differences in China's poverty-stricken areas and promote the poverty reduction and sustainable development in those areas.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: September 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 ISPRS Journal of Photogrammetry and Remote Sensing, Volume 155〈/p〉 〈p〉Author(s): Ruixi Zhu, Li Yan, Nan Mo, Yi Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Supervised scene classification of aerial images is of great importance in land-cover classification. However, annotating the labeled data required for the conventional classifiers and convolutional neural networks (CNNs), costs much manpower and time. Domain adaptation methods can overcome this problem, to some extent, by transferring previously labeled data to the new images, but the classification models trained from the previously labeled data are not discriminative enough for classifying aerial images from other domains because of the data distribution differences caused by the variations in sensors, natural environments, seasons, angles, locations, and so on. In order to solve this problem, we propose a semi-supervised center-based discriminative adversarial learning (SCDAL) framework integrating three parts, namely filtering out easy triplets, proposed hard triplet loss, and the adversarial learning with center loss. In the SCDAL framework, a difficulty measure is proposed to remove easy triplets under the constraint of between-class dissimilarity and intra-class similarity and better distinguish hard triplets. The filtered triplets are then used to train a more discriminative source feature extractor with the proposed hard triplet loss combining the hardest triplet loss and semi-hard triplet loss. Adversarial learning with center loss is also proposed to reduce the feature distribution bias between the source and target feature extractors and increase the discriminative ability of the target feature extractor. The SCDAL framework is tested on two large aerial images as a case study. The experimental results demonstrate that when adequate previously labeled data but limited labeled target data exist, the SCDAL framework is superior to most of the existing domain adaptation methods, with an improvement of at least 3% in overall accuracy. It is also proved that removing easy triplets, proposed hard triplet loss, and the adversarial learning with center loss all help to improve the overall accuracy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Transportation Research Part D: Transport and Environment, Volume 75〈/p〉 〈p〉Author(s): Michał A. Niedzielski, Rafał Kucharski〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Urban spatial structure, transport mode and space-time constraints are known to affect accessibility to activities for a city’s residents. However, most studies measure accessibility from home only and report accessibility in terms of the travel time or number of activities. Such studies neglect the mobility and time budget constraints on people’s accessibility. Furthermore, modal accessibility disparity studies have not considered inequality between modes during the afternoon commute. We examine accessibility to non-work activities by automobile and public transport using spatiotemporal measures that determine the number of minutes people have available to participate in activities, given time budget and activity duration constraints, rather than simply the number of activities. We examine modal accessibility disparity in Warsaw, Poland. Our two major findings are the reverse of findings in previous studies: that disparity shifts toward public transport as the activity duration increases and the travel time decreases; and that it shifts toward public transport with increasing distance away from the city center.〈/p〉〈/div〉 〈/div〉