ALBERT

Beschreibung: Effects of polar stratospheric clouds in the Nimbus 7 LIMS Version 6 data set Ellis Remsberg and V. Lynn Harvey Atmos. Meas. Tech., 9, 2927-2946, doi:10.5194/amt-9-2927-2016, 2016 Emissions from polar stratospheric cloud (PSC) particles affect the retrieved ozone and water vapor from the Limb Infrared Monitor of the Stratosphere (LIMS) satellite experiment. Threshold criteria are applied to the retrieved ozone for the detection and screening of those effects. The PSC effects correlate very well with regions of coldest temperatures (

Beschreibung: A Polarimetric Scattering Database for Non-spherical Ice Particles at MicrowaveWavelengths Yinghui Lu, Zhiyuan Jiang, Kultegin Aydin, Johannes Verlinde, Eugene E. Clothiaux, and Giovanni Botta Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-228,2016 Manuscript under review for AMT (discussion: open, 0 comments) The database contains the complete(polarimatric) scattering information for different types of ice particles at different incident and scattered radiation directions at 4 microwave wavelengths. These results are useful for understanding the dependence of ice-particle scattering properties on ice-particle orientation with respect to the incident and scattered radiation. It is also useful in ice property retrievals, radar forward simulation.

Beschreibung: Identification of the cloud base height over the central Himalayan region: Intercomparison of Ceilometer and Doppler Lidar K. K. Shukla, K. Niranjan Kumar, D. V. Phanikumar, R. K. Newsom, V. R. Kotamarthi, T. B. M. J. Ouarda, and M. V. Ratnam Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-162,2016 Manuscript under review for AMT (discussion: open, 0 comments) Estimation of Cloud base height was carried out by using various ground based instruments (Doppler Lidar and Ceilometer) and satellite datasets (MODIS) over central Himalayan region for the first time. The present study demonstrates the potential of Doppler Lidar in precise estimation of cloud base height and updraft velocities. More such deployments will be invaluable inputs for regional weather prediction models over complex Himalayan terrains.

Beschreibung: Stratospheric Air Sub-sampler (SAS) and its application to analysis of Δ 17 O(CO 2 ) from small air samples collected with an AirCore Dorota Janina Mrozek, Carina van der Veen, Magdalena E. G. Hofmann, Huilin Chen, Rigel Kivi, Pauli Heikkinen, and Thomas Röckmann Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-124,2016 Manuscript under review for AMT (discussion: open, 0 comments) Stratospheric Air Sub-sampler (SAS) is a device to collect and to store the stratospheric profile of air collected with an AirCore (Karion et al, 2010) in numerous sub-samples. The sub-samples (each of 25 mL at ambient temperature and pressure) can be later introduced to the continuous flow systems to measure for example the isotopic composition of CO 2 . The performance of the coupled system is demonstrated for a set of air samples from an AirCore flight in November 2014 near Sodankylä, Finland.

Beschreibung: Real time retrieval of volcanic cloud particles and SO 2 by satellite using an improved simplified approach Sergio Pugnaghi, Lorenzo Guerrieri, Stefano Corradini, and Luca Merucci Atmos. Meas. Tech., 9, 3053-3062, doi:10.5194/amt-9-3053-2016, 2016 Volcanic plume removal (VPR) is a procedure developed to retrieve the ash optical depth, effective radius and mass, and sulfur dioxide mass contained in a volcanic cloud from the thermal radiance at 8.7, 11, and 12 µm. It is based on an estimation of a virtual image representing what the sensor would have seen in a multispectral thermal image if the volcanic cloud were not present. Ash and sulfur dioxide were retrieved by the first version of the VPR using a very simple atmospheric model that ignored the layer above the volcanic cloud. This new version takes into account the layer of atmosphere above the cloud as well as thermal radiance scattering along the line of sight of the sensor. In addition to improved results, the new version also offers an easier and faster preliminary preparation and includes other types of volcanic particles (andesite, obsidian, pumice, ice crystals, and water droplets). As in the previous version, a set of parameters regarding the volcanic area, particle types, and sensor is required to run the procedure. However, in the new version, only the mean plume temperature is required as input data. In this work, a set of parameters to compute the volcanic cloud transmittance in the three quoted bands, for all the aforementioned particles, for both Mt. Etna (Italy) and Eyjafjallajökull (Iceland) volcanoes, and for the Terra and Aqua MODIS instruments is presented. Three types of tests are carried out to verify the results of the improved VPR. The first uses all the radiative transfer simulations performed to estimate the above mentioned parameters. The second one makes use of two synthetic images, one for Mt. Etna and one for Eyjafjallajökull volcanoes. The third one compares VPR and Look-Up Table (LUT) retrievals analyzing the true image of Eyjafjallajökull volcano acquired by MODIS aboard the Aqua satellite on 11 May 2010 at 14:05 GMT.

Beschreibung: Evaluation of IWV from the numerical weather prediction WRF model with PPP GNSS processing for Bulgaria Tzvetan Simeonov, Dmitry Sidorov, Felix Norman Teferle, Georgi Milev, and Guergana Guerova Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-152,2016 Manuscript under review for AMT (discussion: open, 0 comments) Global Navigation Satellite Systems (GNSS) meteorology is an established operational service providing hourly updated GNSS tropospheric products to the National Meteorologic Services (NMS) in Europe. In the last decade through the ground-based GNSS network densification and new processing strategies like Precise Point Positioning (PPP) it has become possible to obtain sub-hourly tropospheric products for monitoring severe weather events. In this work one year (January–December 2013) of sub-hourly GNSS tropospheric products (Zenith Total Delay) are computed using the PPP strategy for seven stations in Bulgaria. In order to take advantage of the sub-hourly GNSS data to derive Integrated Water Vapour (IWV) surface pressure and temperature with similar temporal resolution is required. As the surface observations are on 3 hourly basis the first step is to compare the surface pressure and temperature from numerical weather prediction model Weather Forecasting and Research (WRF) with observations at three synoptic stations in Bulgaria. The mean difference between the two data-sets for 1) surface pressure is less than 0.5 hPa and the correlation is over 0.989, 2) temperature the largest mean difference is 1.1 °C and the correlation coefficient is over 0.957 and 3) IWV mean difference is in range 0.1–1.1 mm. The evaluation of WRF on annual bases shows IWV underestimation between 0.5 and 1.5 mm at five stations and overestimation at Varna and Rozhen. Varna and Rozhen have also much smaller correlation 0.9 and 0.76. The study of the monthly IWV variation shows that at those locations the GNSS IWV has unexpected drop in April and March respectively. The reason for this drop is likely problems with station raw data. At the remaining 5 stations a very good agreement between GNSS and WRF is observed with high correlation during the cold part of 2013 i.e. March, October and December (0.95) and low correlation during the warm part of 2013 i.e. April to August (below 0.9). The diurnal cycle of the WRF model shows a dry bias in the range of 0.5-1.5 mm. Between 00 and 01 UTC the GNSS IWV tends to be underestimate IWV which is likely due to the processing window used. The precipitation efficiency from GNSS and WRF show very good agreement on monthly bases with a maximum in May-June and minimum in August–September. The annual precipitation efficiency in 2013 at Lovech and Burgas is about 6 %.

Beschreibung: Effects of Multiple Doppler Radar data assimilation on the numerical simulation of a Flash Flood Event during the HyMeX campaign Ida Maiello, Sabrina Gentile, Rossella Ferretti, Luca Baldini, Nicoletta Roberto, Errico Picciotti, Pier Paolo Alberoni, and Frank S. Marzano Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-320,2016 Manuscript under review for HESS (discussion: open, 0 comments) An analysis to evaluate the impact of assimilating multiple radar data with a three dimensional variational (3D-Var) system on a heavy precipitation event is presented. The main goal is to establish a general methodology to quantitatively assess the performance of flash-flood numerical weather prediction at mesoscale. In this respect, during the first Special Observation Period (SOP1) of HyMeX (Hydrological cycle in the Mediterranean Experiment) campaign several Intensive Observing Periods (IOPs) were launched and nine occurred in Italy. Among them IOP4 is chosen for this study because of its low predictability. This event hit central Italy on 14 September 2012 producing heavy precipitation and causing several damages. Data taken from three C-band radars running operationally during the event are assimilated to improve high resolution initial conditions. In order to evaluate the impact of the assimilation procedure at different horizontal resolution and to assess the impact of assimilating multiple radars data, several experiments using Weather Research and Forecasting (WRF) model are performed. Finally, the statistical indexes as accuracy, equitable threat score, false alarm ratio and frequency bias are used to objectively compare the experiments, using rain gauges data as benchmark.

Beschreibung: On the propagation of diel signals in river networks using analytic solutions of flow equations Morgan Fonley, Ricardo Mantilla, Scott J. Small, and Rodica Curtu Hydrol. Earth Syst. Sci., 20, 2899-2912, doi:10.5194/hess-20-2899-2016, 2016 We design and implement a theoretical experiment to show that, under low-flow conditions, observed streamflow discrepancies between early and late summer can be attributed to different flow velocities in the river network. By developing an analytic solution to represent flow along a given river network, we emphasize the dependence of streamflow amplitude and time delay on the geomorphology of the network. We also simulate using a realistic river network to highlight the effects of scale.

Beschreibung: Looking beyond general metrics for model comparison – lessons from an international model intercomparison study Tanja de Boer-Euser, Laurène Bouaziz, Jan De Niel, Claudia Brauer, Benjamin Dewals, Gilles Drogue, Fabrizio Fenicia, Benjamin Grelier, Jiri Nossent, Fernando Pereira, Hubert Savenije, Guillaume Thirel, and Patrick Willems Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-339,2016 Manuscript under review for HESS (discussion: open, 0 comments) In this study the rainfall–runoff models of eight international research groups were compared for a set of subcatchments of the Meuse basin to investigate the influence of certain model components on the modelled discharge. Although the models showed similar performances based on general metrics, clear differences could be observed for specific events. The differences during drier conditions could indeed be linked back to differences in model structures.

Beschreibung: Comparison of MODIS and VIIRS cloud properties with ARM ground-based observations over Finland Moa K. Sporre, Ewan J. O'Connor, Nina Håkansson, Anke Thoss, Erik Swietlicki, and Tuukka Petäjä Atmos. Meas. Tech., 9, 3193-3203, doi:10.5194/amt-9-3193-2016, 2016 Satellite measurements of cloud top height and liquid water path are compared to ground-based remote sensing to evaluate the satellite retrievals. The overall performance of the satellite retrievals of cloud top height are good, but they become more problematic when several layers of clouds are present. The liquid water path retrievals also agree well, and the average differences are within the estimated measurement uncertainties.

Beschreibung: Remote sensing of tropospheric turbulence using GPS radio occultation Esayas Shume and Chi Ao Atmos. Meas. Tech., 9, 3175-3182, doi:10.5194/amt-9-3175-2016, 2016 Radio occultation (RO) measurements are sensitive to the small-scale irregularities in the atmosphere. In this study, we present a new technique to estimate tropospheric turbulence strength (namely, scintillation index) by analyzing RO amplitude fluctuations in impact parameter domain. GPS RO observations from the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) satellites enabled us to calculate global maps of scintillation measures, revealing the seasonal, latitudinal, and longitudinal characteristics of the turbulent troposphere. Such information are both difficult and expensive to obtain especially over the oceans. To verify our approach, simulation experiments using the multiple phase screen (MPS) method were conducted. The results show that scintillation indices inferred from the MPS simulations are in good agreement with scintillation measures estimated from COSMIC observations.

Beschreibung: CFC-11, CFC-12 and HCFC-22 ground-based remote sensing FTIR measurements at Reunion Island and comparisons with MIPAS/ENVISAT data Minqiang Zhou, CCorinne Vigouroux, Bavo Langerock, Pucai Wang, Geoff Dutton, Christian Hermans, Nicolas Kumps, Jean-Marc Metzger, Geoff Toon, and Martine De Mazière Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-235,2016 Manuscript under review for AMT (discussion: open, 0 comments) Profiles of CFC-11, CFC-12 and HCFC-22 have been obtained from FTIR measurements above the Saint-Denis and Maïdo sites at Reunion Island (21ºS, 55ºE) with low vertical resolution. The trends derived from the FTIR measurements are -0.86±0.12% and 2.75±0.12% for CFC-11 and HCFC-22, respectively, for the period 2004 to 2016 , and -0.76±0.05% for CFC-12 for 2009 to 2016, which are consistent with ground-based in-situ observations. Our FTIR data and the collocated MIPAS data are in good agreement.

Beschreibung: Evaluation And Attribution Of OCO-2 XCO 2 Uncertainties John Worden, Gary Doran, Susan Kulawik, Annmarie Eldering, David Crisp, Chris Frankenberg, Christian O'Dell, and Kevin Bowman Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-175,2016 Manuscript under review for AMT (discussion: open, 0 comments) This paper evaluates the uncertainties of the total column carbon dioxide (XCO 2 ) measurements from the NASA OCO-2 instrument by comparing observed variations in small geographical regions to the calculated uncertainties of the data within this region. In general we find that the XCO 2 uncertainties are consistent with calculated values of approximately 0.2 ppm over the ocean whereas variations over land likely have larger uncertainties of at least ~ 0.7 ppm.

Beschreibung: River water quality changes in New Zealand over 26 years (1989–2014): Response to land use and land disturbance Jason P. Julian, Kirsten M. de Beurs, Braden Owsley, Robert J. Davies-Colley, and Anne-Gaelle E. Ausseil Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-323,2016 Manuscript under review for HESS (discussion: open, 0 comments) New Zealand (NZ) is a natural laboratory for investigating water quality responses to land use change because its landscape is managed intensively. We interpreted water quality state and trends (1989–2014) of 77 river sites across NZ. We show that the greatest long-term impacts on river water quality in NZ have been densely stocked pastures (due to high nutrient inputs), followed by plantation forestry (due to sediment/nutrient runoff during harvesting).

Beschreibung: A post-wildfire response in cave dripwater chemistry Gurinder Nagra, Pauline C. Treble, Martin S. Andersen, Ian J. Fairchild, Katie Coleborn, and Andy Baker Hydrol. Earth Syst. Sci., 20, 2745-2758, doi:10.5194/hess-20-2745-2016, 2016 Our current understanding of wildfires on Earth is filled with knowledge gaps. One reason for this is our poor record of fire in natural archives. We open the possibility for speleothems to be "a missing piece to the fire-puzzle". We find by effecting surface evaporation and transpiration rates, wildfires can have a multi-year impact on speleothem, forming dripwater hydrology and chemistry. We open a new avenue for speleothems as potential palaeo-fire archives.

Beschreibung: Improving together: better science writing through peer learning Mathew A. Stiller-Reeve, Céline Heuzé, William T. Ball, Rachel H. White, Gabriele Messori, Karin van der Wiel, Iselin Medhaug, Annemarie H. Eckes, Amee O'Callaghan, Mike J. Newland, Sian R. Williams, Matthew Kasoar, Hella Elisa Wittmeier, and Valerie Kumer Hydrol. Earth Syst. Sci., 20, 2965-2973, doi:10.5194/hess-20-2965-2016, 2016 Scientific writing must improve and the key to long-term improvement of scientific writing lies with the early-career scientist (ECS). We introduce the ClimateSnack project, which aims to motivate ECSs to start writing groups around the world to improve their skills together. Writing groups offer many benefits but can be a challenge to keep going. Several ClimateSnack writing groups formed, and this paper examines why some of the groups flourished and others dissolved.

Beschreibung: Vertical profiles of aerosol optical properties and the solar heating rate estimated by combining sky radiometer and lidar measurements Rei Kudo, Tomoaki Nishizawa, and Toshinori Aoyagi Atmos. Meas. Tech., 9, 3223-3243, doi:10.5194/amt-9-3223-2016, 2016 An algorithm for estimating the vertical profiles of the aerosol physical and optical properties, and the solar heating rate from combining sky radiometer and lidar measurements was proposed. The validity and performance of the algorithm were shown by the intensive sensitivity tests using simulated data for different aerosol profiles and the application to the actual measurements in Tsukuba, Japan.

Beschreibung: Intercomparison of aerosol extinction profiles retrieved from MAX-DOAS measurements U. Frieß, H. Klein Baltink, S. Beirle, K. Clémer, F. Hendrick, B. Henzing, H. Irie, G. de Leeuw, A. Li, M. M. Moerman, M. van Roozendael, R. Shaiganfar, T. Wagner, Y. Wang, P. Xie, S. Yilmaz, and P. Zieger Atmos. Meas. Tech., 9, 3205-3222, doi:10.5194/amt-9-3205-2016, 2016 This article describes the first direct comparison of aerosol extinction profiles from Multi-Axis DOAS measurements of the oxygen collision complex using five different retrieval algorithms. A comparison of the retrieved profiles with co-located aerosol measurements shows good agreement with respect to profile shape and aerosol optical thickness. This study shows that MAX-DOAS is a simple, versatile and cost-effective method for the measurement of aerosol properties in the lower troposphere.

Beschreibung: Assessing the Performance of Troposphere Tomographic Modeling Using Multi-Source Water Vapor Data During Hong Kong’s Rainy Season from May to October 2013 Biyan Chen and Zhizhao Liu Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-158,2016 Manuscript under review for AMT (discussion: open, 0 comments) A multi-source water vapor tomography model is developed using data from GPS (Global Positioning System), radiosonde, WVR (Water Vapor Radiometer), NWP (Numerical Weather Prediction), AERONET (AErosol RObotic NETwork) sunphotometer and synoptic stations. Results show that the assimilation of multi-source data can increase the quality of tomographic solution. Evaluation shows that tomography model is robust during heavy rain conditions and it can contribute to severe weather forecasting.

Beschreibung: Identification of Tower Wake Distortions Using Sonic Anemometer and Lidar Measurements Katherine McCaffrey, Paul Quelet, Aditya Choukulkar, James M. Wilczak, Daniel E. Wolfe, Steven Oncley, Alan Brewer, Mithu Debnath, Ryan Ashton, G. Valerio Iungo, and Julie K. Lundquist Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-179,2016 Manuscript under review for AMT (discussion: open, 0 comments) During the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) field campaign, the wake and flow distortion from a 300-meter meteorological tower was identified using pairs of sonic anemometers mounted on opposite sides of the tower, as well as profiling and scanning lidars. Wind speed deficits up to 50 % and TKE increases of two orders of magnitude were observed at wind directions in the wake, along with wind direction differences (flow deflection) outside of the wake.

Beschreibung: Validation of Terrestrial Water Storage Variations as Simulated by Different Global Numerical Models with GRACE Satellite Observations Liangjing Zhang, Henryk Dobslaw, Tobias Stacke, Andreas Güntner, Robert Dill, and Maik Thomas Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-330,2016 Manuscript under review for HESS (discussion: open, 0 comments) Global numerical models perform differently as has been found in some model intercomparison studies, which mainly focused on components as evapotranspiration, soil moisture or runoff. We have applied terrestrial water storage that is estimated from state-of-art post-processing method to validate four global numerical models and try to identify the advantages and deficiencies of a certain model. GRACE based TWS demonstrates its additional benefits to improve models in future.

Beschreibung: Model Study on Potential Contributions of the Proposed Huangpu Gate to Flood Control in Taihu Lake Basin Hanghui Zhang, Shuguang Liu, Jianchun Ye, and Pat Yeh Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-310,2016 Manuscript under review for HESS (discussion: open, 0 comments) The Taihu Lake basin is located in the hinterland of the Yangtze River Delta. Constructing a gate at the mouth of the Huangpu River is considered one of the effective solutions to the basin's flooding problems. The pattern of river flow changes from bi-directional to unidirectional flow when the estuary gate is operated. It is concluded that the Huangpu River with a proposed gate is more effective than a natural channel, and its beneficiaries include the lake and the related surrounding areas.

Beschreibung: Hydrological modeling in glacierized catchments of Central Asia: status and challenges Yaning Chen, Weihong Li, Gonghuan Fang, and Zhi Li Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-325,2016 Manuscript under review for HESS (discussion: open, 0 comments) This paper reviews the status of hydrological modeling in the mountainous region of Central Asia, discussing the limitations of the available models and shedding light on future directions. We conclude that the main sources of uncertainty in hydrological modeling are the input uncertainty and lack of understanding of the hydrological regimes. Future focuses should be on the use of multi-source of input data combined with multi-objective calibration and validation.

Beschreibung: Consequences and mitigation of saltwater intrusion induced by short-circuiting during aquifer storage and recovery (ASR) in a coastal subsurface Koen Gerardus Zuurbier and Pieter Jan Stuyfzand Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-343,2016 Manuscript under review for HESS (discussion: open, 0 comments) The subsurface is increasingly perforated for exploitation of water and energy. This has increased the risk of leakage between originally separated aquifers. It is shown how this leakage can have a very negative impact on the recovery of freshwater during aquifer storage and recovery (ASR) in brackish-saline aquifers. Deep interception of intruding brackish-saline water can mitigate the negative effects and buoyancy of freshwater to some extent, but not completely.

Beschreibung: Simulation study for measurement of horizontal wind profiles in the polar stratosphere and mesosphere using ground-based observations of ozone and carbon monoxide lines in the 230–250 GHz region David A. Newnham, George P. Ford, Tracy Moffat-Griffin, and Hugh C. Pumphrey Atmos. Meas. Tech., 9, 3309-3323, doi:10.5194/amt-9-3309-2016, 2016 We demonstrate the feasibility of measuring polar atmospheric winds over the altitude range 23–97 km using ground-based millimetre-wave Doppler radiometry. Atmospheric and instrument simulations were carried out for Halley station, Antarctica. This remote sensing technique will provide continuous horizontal wind observations in the stratosphere and mesosphere where measurements are currently very limited. The data are needed for meteorological analyses and atmospheric modelling applications.

Beschreibung: Chamber catalogues of optical and fluorescent signatures distinguish bioaerosol classes Mark Hernandez, Anne E. Perring, Kevin McCabe, Greg Kok, Gary Granger, and Darrel Baumgardner Atmos. Meas. Tech., 9, 3283-3292, doi:10.5194/amt-9-3283-2016, 2016 We have performed laboratory experiments examining a large set of known bacterial, fungal and pollen species using a Wideband Integrated Bioaerosol Sensor (WIBS). The instrumental response is shown to be sufficiently distinct for these classes of particles to distinguish between them, and this library will provide a framework for interpretation of UV-induced fluorescence measurements of atmospheric bioaerosol. Atmospheric implications and instrumental considerations are discussed.

Beschreibung: Improved Methodologies for Continuous Flow Analysis of Stable Water Isotopes in Ice Cores Tyler R. Jones, James W. C. White, Eric J. Steig, Bruce H. Vaughn, Valerie Morris, Vasileios Gkinis, Bradley R. Markle, and Spruce W. Schoenemann Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-118,2016 Manuscript under review for AMT (discussion: open, 0 comments) New systems have been developed that continuously melt ice core samples, in contrast to other methods that analyze a single sample at a time. These newer systems are capable of reducing analysis time by many years and improving data set resolution. In this study, we introduce improved methodologies that optimize the speed, accuracy, and precision of a water isotope continuous flow system. The presented system will be used for Antarctic and Greenland ice core projects.

Beschreibung: Validation of COSMIC water vapor data in the upper troposphere and lower stratosphere using MLS, MERRA and ERA-Interim Ming Shangguan, Katja Matthes, Wuke Wang, and Tae-Kwon Wee Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-248,2016 Manuscript under review for AMT (discussion: open, 0 comments) A first validation of the COSMIC Radio Occultation (RO) water vapor data in the upper troposphere and lower stratosphere (UTLS) are presented in this paper. The COSMIC water vapor shows a good agreement with the Microwave limb Sounder (MLS) in both the spatial distribution and the seasonal to interannual variations. It is very valuable for studying the water vapor in the UTLS, thanks to its global coverage, all- weather aptitude and high vertical resolution.

Beschreibung: Harmonization and Diagnostics of MIPAS ESA CH 4 and N 2 O Profiles Using Data Assimilation Quentin Errera, Simone Ceccherini, Yves Christophe, Simon Chabrillat, Michaela I. Hegglin, Alyn Lambert, Richard Ménard, Piera Raspollini, Sergey Skachko, Michiel van Weele, and Kaley A. Walker Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-245,2016 Manuscript under review for AMT (discussion: open, 0 comments) This paper discusses assimilation experiments of methane (CH 4 ) and nitrous oxide (N 2 O) profiles observed by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). Here we focus on data versions 6 and 7 retrieved by the ESA processor. These datasets have been assimilated by the Belgian Assimilation System for Chemical ObsErvations (BASCOE). The CH 4 and N 2 O profiles can be noisy especially in the tropical lower stratosphere. Using the averaging kernels of the observations and a background error covariance matrix – the B matrix, which has been previously calibrated, allows the system to partly remedy this issue and provide assimilated fields that are more regular vertically. In general, there is a good agreement between the BASCOE analyses and independent observations demonstrating the general good quality of these two retrievals provided by MIPAS ESA. Nevertheless, this study also identifies two issues in these datasets. First, time-series of the observations show unexpected discontinuities, due to the calibration method used for the level-1 data. Second, the correlations between BASCOE analyses and independent observations are poor in the lower stratosphere, especially in the tropics, probably due to the presence of outliers in the assimilated data. In this region, we recommend using MIPAS CH 4 and N 2 O observations with caution.

Beschreibung: The European 2015 drought from a hydrological perspective Gregor Laaha, Tobias Gauster, Lena M. Tallaksen, Jean-Philippe Vidal, Kerstin Stahl, Christel Prudhomme, Benedikt Heudorfer, Radek Vlnas, Monica Ionita, Henny A. J. Van Lanen, Mary-Jeanne Adler, Laurie Caillouet, Claire Delus, Miriam Fendekova, Sebastien Gailliez, Jamie Hannaford, Daniel Kingston, Anne F. Van Loon, Luis Mediero, Marzena Osuch, Renata Romanowicz, Eric Sauquet, James H. Stagge, and Wai K. Wong Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-366,2016 Manuscript under review for HESS (discussion: open, 0 comments) In 2015 large parts of Europe were affected by a drought. In terms of low flow magnitude, a region around the Czech Republic was most affected with annual low flows that exhibited return intervals of 100 years and more. In terms of deficit volumes, the geographical centre of the event was in the area of Southern Germany where the drought lasted particularly long. For an assessment of drought impacts on water resources hydrological data is required in addition to the hydro-meteorological indices.

Beschreibung: Hydrological threats for riparian wetlands of international importance – a global quantitative and qualitative analysis Christof Schneider, Martina Flörke, Lucia De Stefano, and Jacob D. Petersen-Perlman Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-350,2016 Manuscript under review for HESS (discussion: open, 0 comments) Riparian wetlands are disappearing worldwide due to altered river hydrology. The WaterGAP3 model is used to compare modified to natural flow regimes at 93 Ramsar sites. Results show that water resource management seriously impairs inundation patterns at 29 % of the sites. New dam initiatives are likely to affect especially wetlands located in South America, Africa, Asia and the Balkan Peninsula. Hotspots for climate change impacts could be Eastern Europe and South America.

Beschreibung: Leaf-scale experiments reveal important omission in the Penman-Monteith equation Stanislaus J. Schymanski and Dani Or Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-363,2016 Manuscript under review for HESS (discussion: open, 0 comments) Most of the rain falling on land is returned to the atmosphere by plant leaves, which release water vapour (transpire) through tiny pores. To better understand this process, we used artificial leaves in a special wind tunnel and discovered major problems with an established approach (PM equation), widely used to quantify transpiration and its sensitivity to climate change. We present an improved set of equations, consistent with experiments and displaying more realistic climate sensitivity.

Beschreibung: Sampling strategies and post-processing methods for increasing the time resolution of organic aerosol measurements requiring long sample-collection times Rob L. Modini and Satoshi Takahama Atmos. Meas. Tech., 9, 3337-3354, doi:10.5194/amt-9-3337-2016, 2016 Aerosol measurement techniques with high detection limits often result in poorly time-resolved measurements. We investigated sampling strategies and post-processing methods for constructing hourly resolved aerosol concentration time series from samples collected for 4 to 8 h. We show that this is an effective way to increase measurement time resolution, and that under realistic experimental conditions, simple methods can perform as well as more sophisticated methods.

Beschreibung: Assessment of land use impact on hydraulic threshold conditions for gully head cut initiation Aliakbar Nazari Samani, Qiuwen Chen, Shahram Khalighi, Robert James Wasson, and Mohammad Reza Rahdari Hydrol. Earth Syst. Sci., 20, 3005-3012, doi:10.5194/hess-20-3005-2016, 2016 We hypothesized that land use had important effects on hydraulic threshold conditions for gully head cut initiation. We investigated the effects using an experimental plot. The results indicated that the use of a threshold value of τ cr  = 35  dyne cm −2 and ω u  = 0.4 Cm S −1 in physically based soil erosion models is susceptible to high uncertainty when assessing gully erosion.

Beschreibung: Mekong River flow and hydrological extremes under climate change Long Phi Hoang, Hannu Lauri, Matti Kummu, Jorma Koponen, Michelle T. H. van Vliet, Iwan Supit, Rik Leemans, Pavel Kabat, and Fulco Ludwig Hydrol. Earth Syst. Sci., 20, 3027-3041, doi:10.5194/hess-20-3027-2016, 2016 We modelled hydrological changes under climate change in the Mekong River, focusing on extreme events. The scenario ensemble shows an intensification of the hydrological cycle under climate change. Annual river flow increases between 5 and 16 % depending on locations. Extreme high flows increase substantially in both magnitude and frequency, posing threats to flood safety in the basin. Extreme low-flow events are projected to reduce as a result of increased river flow during the dry season.

Beschreibung: On the non-stationarity of hydrological response in anthropogenically unaffected catchments: An Australian perspective Hoori Ajami, Ashish sharma, Lawrence E. Band, Jason P. Evans, Narendra K. Tuteja, G. E. Amirthanathan, and Mohammed A. Bari Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-353,2016 Manuscript under review for HESS (discussion: open, 0 comments) We present the first data-based framework for explaining why catchments behave in a non-stationary manner, even when they are unaffected by deforestation or urbanization. The role of vegetation dynamics on stream flow are indicated by similar or greater sensitivity of annual runoff ratio to annual fractional vegetation cover. We formulated a novel ecohydrologic catchment classification framework that incorporates the role of vegetation dynamics on catchment scale water partitioning.

Beschreibung: The Moon as a photometric calibration standard for microwave sensors Martin Burgdorf, Stefan A. Buehler, Theresa Lang, Simon Michel, and Imke Hans Atmos. Meas. Tech., 9, 3467-3475, doi:10.5194/amt-9-3467-2016, 2016 The upper-tropospheric humidity is an essential climate variable, which can be measured with microwave sounders in polar orbits. A stable photometric calibration of these instruments is indispensable for detecting long-term trends. We demonstrate that this can be achieved by using the Moon in a fixed phase as a flux standard for dedicated pitch maneuver observations. This method is particularly suited for future sensors with small beamwidths.

Beschreibung: A new approach for retrieving the UV–vis optical properties of ambient aerosols Nir Bluvshtein, J. Michel Flores, Lior Segev, and Yinon Rudich Atmos. Meas. Tech., 9, 3477-3490, doi:10.5194/amt-9-3477-2016, 2016 Understanding spectrally dependent optical properties of aerosols is needed to quantify the effective radiative forcing due to aerosol–radiation interactions. We describe a new approach to retrieve extensive and intensive optical properties of the aerosol population over 300 to 650 nm wavelength. This new approach was validated with retrieval simulations, laboratory and continuous ambient aerosols measurements. Results showed low errors and good agreement with expected values.

Beschreibung: Bias corrections of GOSAT SWIR XCO 2 and XCH 4 with TCCON data and their evaluation using aircraft measurement data Makoto Inoue, Isamu Morino, Osamu Uchino, Takahiro Nakatsuru, Yukio Yoshida, Tatsuya Yokota, Debra Wunch, Paul O. Wennberg, Coleen M. Roehl, David W. T. Griffith, Voltaire A. Velazco, Nicholas M. Deutscher, Thorsten Warneke, Justus Notholt, John Robinson, Vanessa Sherlock, Frank Hase, Thomas Blumenstock, Markus Rettinger, Ralf Sussmann, Esko Kyrö, Rigel Kivi, Kei Shiomi, Shuji Kawakami, Martine De Mazière, Sabrina G. Arnold, Dietrich G. Feist, Erica A. Barrow, James Barney, Manvendra Dubey, Matthias Schneider, Laura T. Iraci, James R. Podolske, Patrick W. Hillyard, Toshinobu Machida, Yousuke Sawa, Kazuhiro Tsuboi, Hidekazu Matsueda, Colm Sweeney, Pieter P. Tans, Arlyn E. Andrews, Sebastien C. Biraud, Yukio Fukuyama, Jasna V. Pittman, Eric A. Kort, and Tomoaki Tanaka Atmos. Meas. Tech., 9, 3491-3512, doi:10.5194/amt-9-3491-2016, 2016 In this study, we correct the biases of GOSAT XCO 2 and XCH 4 using TCCON data. To evaluate the effectiveness of our correction method, uncorrected/corrected GOSAT data are compared to independent XCO 2 and XCH 4 data derived from aircraft measurements. Consequently, we suggest that this method is effective for reducing the biases of the GOSAT data. We consider that our work provides GOSAT data users with valuable information and contributes to the further development of studies on greenhouse gases.

Beschreibung: Detection of formaldehyde emissions from an industrial zone in the Yangtze-River-Delta region of China using a proton transfer reaction ion-drift chemical ionization mass spectrometer Yan Ma, Yiwei Diao, Bingjie Zhang, Weiwei Wang, Xinrong Ren, Dongsen Yang, Ming Wang, Xiaowen Shi, and Jun Zheng Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-194,2016 Manuscript under review for AMT (discussion: open, 0 comments) Here we reported the development of a PTR-ID-CIMS to investigate industry-related emissions of VOCs in the Yangtze-River-Delta (YRD) region, the largest economic zone in China. We observed strong primary HCHO emissions from the industrial zone that overwhelmed local HCHO secondary formation. These primary HCHO sources can potentially lead to severe local and regional air pollution formation. Therefore, primary industrial HCHO emissions should be strictly monitored and regulated in this region.

Beschreibung: HoloGondel: in-situ cloud observations on a cable car in the Swiss Alps using a holographic imager Alexander Beck, Jan Henneberger, Sarah Schöpfer, and Ulrike Lohmann Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-216,2016 Manuscript under review for AMT (discussion: open, 0 comments) In-situ observations of cloud properties in complex alpine terrain are commonly conducted at mountain-top research stations and limited to single-point measurements. The HoloGondel platform overcomes this limitation by using a cable car to obtain vertical profiles of the microphysical and meteorological cloud parameters. In this work example measurements of the vertical profiles observed in a liquid cloud and a mixed-phase cloud at the Eggishorn in the Swiss Alps are presented.

Beschreibung: Sustainability of water uses in managed hydrosystems: human- and climate-induced changes for the mid-21st century Julie Fabre, Denis Ruelland, Alain Dezetter, and Benjamin Grouillet Hydrol. Earth Syst. Sci., 20, 3129-3147, doi:10.5194/hess-20-3129-2016, 2016 We assess the sustainability of planned water uses in complex mesoscale river basins by modeling water demand and availability under climatic and anthropogenic changes. We present an analysis through indicators that relate to water management goals. The impacts of climate projections on both water availability and demand question the water allocations and environmental constraints currently planned for the coming decades. This work brings an essential long-term perspective to water sharing plans.

Beschreibung: Satellite observation of atmospheric methane: intercomparison between AIRS and GOSAT TANSO-FTS retrievals Mingmin Zou, Xiaozhen Xiong, Naoko Saitoh, Juying Warner, Ying Zhang, Liangfu Chen, Fuzhong Weng, and Meng Fan Atmos. Meas. Tech., 9, 3567-3576, doi:10.5194/amt-9-3567-2016, 2016 Both AIRS and GOSAT TANSO-FTS TIR have been used to retrieve atmosphere CH 4 . The purpose of an intercomparison is to provide useful information to users on the characteristics of these two different products when they investigate the spatial and temporal variation of CH 4 . On the other hand, AIRS V6 CH 4 data were already validated by comparing with aircraft data. This intercomparison is also a kind of indirect validation to GOSAT data.

Beschreibung: Assessment of errors and biases in retrievals of X CO 2 , X CH 4 , X CO , and X N 2 O from a 0.5 cm –1 resolution solar-viewing spectrometer Jacob K. Hedelius, Camille Viatte, Debra Wunch, Coleen M. Roehl, Geoffrey C. Toon, Jia Chen, Taylor Jones, Steven C. Wofsy, Jonathan E. Franklin, Harrison Parker, Manvendra K. Dubey, and Paul O. Wennberg Atmos. Meas. Tech., 9, 3527-3546, doi:10.5194/amt-9-3527-2016, 2016 Portable FTS instruments with lower resolution are being used to measure gases (including CO 2 , CH 4 , CO, and N 2 O) in the atmosphere. We compared measurements from four of these instruments for a few weeks, and with one for nearly a year to a higher resolution TCCON standard. We also performed tests to assess performance under different atmospheric and instrumental conditions. We noted consistent offsets in the short-term (~1 month); more research is still needed to assess precision longer term.

Beschreibung: Information Content and Sensitivity of the 3β + 2α Lidar Measurement System for Aerosol Microphysical Retrievals Sharon P. Burton, Eduard Chemyakin, Xu Liu, Kirk Knobelspiesse, Snorre Stamnes, Patricia Sawamura, Richard H. Moore, Chris A. Hostetler, and Richard A. Ferrare Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-240,2016 Manuscript under review for AMT (discussion: open, 0 comments) Retrievals of aerosol microphysics exist for ground-based, airborne, and future space-borne lidar measurements. We investigate the information content of a lidar measurement system, using only a forward model but no explicit inversion. The simplified aerosol used here is applicable as a best case for all retrievals in the absence of additional constraints. We report (1) information content of the measurements; (2) uncertainties on the retrieved parameters; and (3) sources of compensating errors.

Beschreibung: How to reliably detect molecular clusters and nucleation mode particles with Neutral cluster and Air Ion Spectrometer (NAIS) Hanna E. Manninen, Sander Mirme, Aadu Mirme, Tuukka Petäjä, and Markku Kulmala Atmos. Meas. Tech., 9, 3577-3605, doi:10.5194/amt-9-3577-2016, 2016 This paper reports a standard operation procedure (SOP) for a Neutral cluster and Air Ion Spectrometer (NAIS) to detect small clusters and nucleation mode particles. The NAIS measures number size distributions of charged and neutral aerosol particles. The SOP is needed to provide comparable results measured by NAIS users around the world. The work is based on discussions between the NAIS users (lead by University of Helsinki, Finland) and the NAIS manufacturer (Airel Ltd., Estonia).

Beschreibung: Validation of Aura MLS retrievals of temperature, water vapour and ozone in the upper troposphere and lower–middle stratosphere over the Tibetan Plateau during boreal summer Xiaolu Yan, Jonathon S. Wright, Xiangdong Zheng, Nathaniel J. Livesey, Holger Vömel, and Xiuji Zhou Atmos. Meas. Tech., 9, 3547-3566, doi:10.5194/amt-9-3547-2016, 2016 We evaluate Aura Microwave Limb Sounder retrievals of temperature, water vapour and ozone over the eastern Tibetan Plateau against measurements from balloon-borne instruments. The newest version of the retrievals (v4) represents a slight improvement over the previous version, particularly with respect to data yields and upper tropospheric ozone. We identify several biases that did not appear in evaluations conducted elsewhere, highlighting the unique challenges of remote sensing in this region.

Beschreibung: The ALTIUS mission Didier Fussen, Emmanuel Dekemper, Quentin Errera, Ghislain Franssens, Nina Mateshvili, Didier Pieroux, and Filip Vanhellemont Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-213,2016 Manuscript under review for AMT (discussion: open, 0 comments) Recently, the ALTIUS mission has been declared as an element compliant to the ESA Earth Watch programme. The paper identifies the general scientific context of the project and derives the mission, instrument and scientific products requirements. The general design of the payload and platform systems is discussed. The preliminary data processing chain is presented, from telemetry data to retrieved geophysical profiles, with a complementary data assimilation level.

Beschreibung: Intercomparison study and optical asphericity measurements of small ice particles in the CERN CLOUD experiment Leonid Nichman, Emma Järvinen, James Dorsey, Paul Connolly, Jonathan Dupplisy, Claudia Fuchs, Karoliina Ignatius, Kamalika Sengupta, Frank Stratmann, Ottmar Möhler, Martin Schnaiter, and Martin Gallagher Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-205,2016 Manuscript under review for AMT (discussion: open, 0 comments) Optical probes are frequently used for the detection of cloud particles. The detected microphysical properties may affect particle growth and accretion mechanisms and the light scattering properties of cirrus clouds. In the CLOUD chamber study at CERN, we compared four optical measurement techniques. We show that shape derivation alone is not sufficient to determine the phase of the small cloud particles. Surface complexity was found to be an important parameter for phase discrimination.

Beschreibung: Modeling liquid water transport in snow under rain-on-snow conditions – considering preferential flow Sebastian Würzer, Nander Wever, Roman Juras, Michael Lehning, and Tobias Jonas Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-351,2016 Manuscript under review for HESS (discussion: open, 0 comments) We discuss a dual-domain water transport model in a physics based snowpack model to account for preferential flow (PF) in addition to matrix flow. Yet so far no operationally used snow model was explicitly accounting for PF. The new approach is compared to existing water transport models and validated against in-situ data from sprinkling and natural rain-on-snow (ROS) events. Our work demonstrates the benefit of considering PF in modeling hourly snowpack runoff, especially during ROS conditions.

Beschreibung: Can integrative catchment management mitigate future water quality issues caused by climate change and socio-economic development? Mark Honti, Nele Schuwirth, Jörg Rieckermann, and Christian Stamm Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-297,2016 Manuscript under review for HESS (discussion: open, 0 comments) Catchments are complex systems where water quantity, quality and the provided ecological services are determined by interacting physical, chemical, biological, economic, and social factors. The awareness of these interactions led to the prevailing catchment management paradigm of Integrated Water Resources Management. The design and evaluation of solutions for integrated water resources management requires to predict changes of local or regional water quality, which requires integrated approach for modeling too. On one hand, integrated models have to be comprehensive enough to cover the aspects relevant for management decisions, allow for mapping of global change processes – as climate change, population growth, migration, and socio-economic development – to the regional and local contexts. On the other hand, models have to be sufficiently simple and fast enough to apply proper methods of uncertainty analysis, which can consider model structure deficits and propagate errors through the chain of submodels. Here, we present an integrated catchment model satisfying both objectives. The conceptual "iWaQa" model was developed to support the integrated management of small streams. It can predict both traditional water quality parameters like nutrients and a wide set of organic micropollutants originating from plant and material protection products. Due to the model's simplicity, it allows for a full, propagative analysis of predictive uncertainty, including certain structural and input errors. The usefulness of the model is demonstrated by predicting future water quality in a small catchment with mixed land use in the Swiss Plateau. The focus of our study is the change of water quality over the next decades driven by climate change, population growth or decline, socio-economic development and the implementation of management strategies for improving water quality. Our results indicate that input and model structure uncertainties are the most influential factors on certain water quality parameters and in these cases the uncertainty of modeling is already very high for the present conditions. Nevertheless, a proper quantification of today's uncertainty can make the management fairly robust for the foreseen range of possible evolution into the next decades. With a time-horizon of 2050, it seems that human land use and management decisions have a larger influence on water quality than climate change. However, the analysis of single climate model chains indicates that the importance of climate grows when a certain climate prediction is considered instead of the ensemble forecast.

Beschreibung: Improved large-scale hydrological modelling through the assimilation of streamflow and downscaled satellite soil moisture observations Patricia López López, Niko Wanders, Jaap Schellekens, Luigi J. Renzullo, Edwin H. Sutanudjaja, and Marc F. P. Bierkens Hydrol. Earth Syst. Sci., 20, 3059-3076, doi:10.5194/hess-20-3059-2016, 2016 We perform a joint assimilation experiment of high-resolution satellite soil moisture and discharge observations in the Murrumbidgee River basin with a large-scale hydrological model. Additionally, we study the impact of high- and low-resolution meteorological forcing on the model performance. We show that the assimilation of high-resolution satellite soil moisture and discharge observations has a significant impact on discharge simulations and can bring them closer to locally calibrated models.

Beschreibung: Application of tritium in precipitation and baseflow in Japan: a case study of groundwater transit times and storage in Hokkaido watersheds Maksym A. Gusyev, Uwe Morgenstern, Michael K. Stewart, Yusuke Yamazaki, Kazuhisa Kashiwaya, Terumasa Nishihara, Daisuke Kuribayashi, Hisaya Sawano, and Yoichi Iwami Hydrol. Earth Syst. Sci., 20, 3043-3058, doi:10.5194/hess-20-3043-2016, 2016 Tritium-estimated groundwater mean transit times (MTTs) and storage volumes provide useful information for water resources management especially during droughts. In Hokkaido, we find that (1) one tritium measurement at baseflow is already sufficient to estimate MTT for some catchments, (2) the hydrogeological settings control tritium transit times of subsurface groundwater storage at baseflow, and (3) in future, one tritium measurement will be sufficient to estimate MTT in most Japanese catchments.

Beschreibung: An empirical method to correct for temperature-dependent variations in the overlap function of CHM15k ceilometers Maxime Hervo, Yann Poltera, and Alexander Haefele Atmos. Meas. Tech., 9, 2947-2959, doi:10.5194/amt-9-2947-2016, 2016 Imperfections in a lidar's overlap function lead to artefacts in the lidar (Light Detection and Ranging) signals. These artefacts can erroneously be interpreted as an aerosol gradient or, in extreme cases, as a cloud base leading to false cloud detection. In this study an algorithm is presented to correct such artefacts. The algorithm is completely automatic and does not require any intervention on site. It is therefore suited for use in large automatic lidar networks.

Beschreibung: Redox controls on methane formation, migration and fate in shallow aquifers Pauline Humez, Bernhard Mayer, Michael Nightingale, Veith Becker, Andrew Kingston, Stephen Taylor, Guy Bayegnak, Romain Millot, and Wolfram Kloppmann Hydrol. Earth Syst. Sci., 20, 2759-2777, doi:10.5194/hess-20-2759-2016, 2016 Development of unconventional energy resources if often associated with public concerns regarding potential contamination of shallow groundwater due to methane leakage. We combined chemical and isotopic analyses of gas and water samples obtained from shallow aquifers in Alberta (Canada) to assess baseline methane sources and found that 〉 67 % of the samples contained biogenic methane formed in situ in the aquifers. There was no evidence of deep thermogenic methane migration into shallow aquifers.

Beschreibung: Spatial and Temporal Variability in Baseflow in the Mattole River Headwaters, California, USA Nathan Queener and Andrew P. Stubblefield Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-300,2016 Manuscript under review for HESS (discussion: open, 0 comments) Understanding controls on stream low flow is critical for managing aquatic resources. Baseflows in small river basins in northern California, USA were found to be quite divergent. The difference in water yield was much greater than the difference in precipitation. Steep, high elevation areas, dissected by many channels, had the highest baseflow. The positive correlation between basin steepness and flow is thought to result from greater basin storage capacity in thick weathered bedrock layers.

Beschreibung: EARLINET Single Calculus Chain – technical – Part 2: Calculation of optical products Ina Mattis, Giuseppe D'Amico, Holger Baars, Aldo Amodeo, Fabio Madonna, and Marco Iarlori Atmos. Meas. Tech., 9, 3009-3029, doi:10.5194/amt-9-3009-2016, 2016 We present an automated software tool for the retrieval of profiles of optical particle properties from lidar signals. This tool is one of the modules of the Single Calculus Chain of the European Aerosol Research Lidar Network (EARLINET). It allows for the analysis of the data of many different lidar systems of EARLINET in an automated, unsupervised way.

Beschreibung: The role of cloud contamination, aerosol layer height and aerosol model in the assessment of the OMI near-UV retrievals over the ocean Santiago Gassó and Omar Torres Atmos. Meas. Tech., 9, 3031-3052, doi:10.5194/amt-9-3031-2016, 2016 Aerosol optical depths derived by the OMI near-UV algorithm are evaluated against independent observations over the ocean. The comparison resulted in differences within the expected levels of uncertainty. In addition, in clear sky conditions, the retrieved AODs compare well with independent measurements but they are biased high in partially cloud-contaminated pixels. Additional sources of discrepancies are documented and will be corrected in future versions of the algorithm.

Beschreibung: Intercomparison of total column ozone data from the Pandora spectrophotometer with Dobson, Brewer, and OMI measurements over Seoul, Korea Jiyoung Kim, Jhoon Kim, Hi-Ku Cho, Jay Herman, Sang Seo Park, HyunKwang Lim, Jae-hwan Kim, and Koji Miyagawa Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-146,2016 Manuscript under review for AMT (discussion: open, 0 comments) Total column ozone (TCO) has been obtained by various ground-based and spaceborne instruments with high accuracy. Here, daily TCO measured by Pandora spectrophotometer (#19) installed since (DRAGON)-NE Asia Campaign (2012) was intercompared using Dobson (#124), Brewer (#148) and OMI measurements from March 2012 to March 2014 at Yonsei University, Seoul, Korea. And the result showed that Pandora TCO is in highly good agreement with other measurements.

Beschreibung: Benchmark campaign and case study episode in central Europe for development and assessment of advanced GNSS tropospheric models and products Jan Douša, Galina Dick, Michal Kačmařík, Radmila Brožková, Florian Zus, Hugues Brenot, Anastasia Stoycheva, Gregor Möller, and Jan Kaplon Atmos. Meas. Tech., 9, 2989-3008, doi:10.5194/amt-9-2989-2016, 2016 GNSS products provide observations of atmospheric water vapour. Advanced tropospheric products focus on ultra-fast and high-resolution zenith total delays (ZTDs), horizontal gradients and slant delays, all suitable for rapid-cycle numerical weather prediction (NWP) and severe weather event monitoring. The GNSS4SWEC Benchmark provides a complex data set for developing and assessing these products, with initial focus on reference ZTDs and gradients derived from several NWP and dense GNSS networks.

Beschreibung: Operation of the Airmodus A11 nano Condensation Nucleus Counter at various inlet pressures and various operation temperatures, and design of a new inlet system Juha Kangasluoma, Alessandro Franchin, Jonahtan Duplissy, Lauri Ahonen, Frans Korhonen, Michel Attoui, Jyri Mikkilä, Katrianne Lehtipalo, Joonas Vanhanen, Markku Kulmala, and Tuukka Petäjä Atmos. Meas. Tech., 9, 2977-2988, doi:10.5194/amt-9-2977-2016, 2016 The paper describes technical aspects of using the Airmodus A11 nCNC at various inlet pressures and how temperature selection affects the performance of the instrument. We also present a sampling box to minimize the inlet losses and make use of the instrument more convenient.

Beschreibung: Effect of secondary organic aerosol coating thickness on the real-time detection and characterization of biomass burning soot by two particle mass spectrometers Adam T. Ahern, R. Subramanian, Georges Saliba, Eric M. Lipsky, Neil M. Donahue, and Ryan C. Sullivan Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-201,2016 Manuscript under review for AMT (discussion: open, 0 comments) The SP-AMS exhibited a different sensitivity to black carbon versus potassium as more SOA mass was condensed onto biomass burning particles. The SP-AMS’s sensitivity to BC mass did not plateau following successive SOA coatings, despite achieving high OA : BC mass ratios 〉 9. A laser ablation single-particle mass spectrometer exhibited a linear response to the condensed SOA mass on individual soot particles, demonstrating its ability to obtain mass quantitative measurements from complex matrices.

Beschreibung: Variations of global and continental water balance components as impacted by climate forcing uncertainty and human water use Hannes Müller Schmied, Linda Adam, Stephanie Eisner, Gabriel Fink, Martina Flörke, Hyungjun Kim, Taikan Oki, Felix Theodor Portmann, Robert Reinecke, Claudia Riedel, Qi Song, Jing Zhang, and Petra Döll Hydrol. Earth Syst. Sci., 20, 2877-2898, doi:10.5194/hess-20-2877-2016, 2016 The assessment of water balance components of the global land surface by means of hydrological models is affected by large uncertainties, in particular related to meteorological forcing. We analyze the effect of five state-of-the-art forcings on water balance components at different spatial and temporal scales modeled with WaterGAP. Furthermore, the dominant effect (precipitation/human alteration) for long-term changes in river discharge is assessed.

Beschreibung: Comparison of the Arctic upper-air temperatures from radiosonde and radio occultation observations Liang Chang, Lixin Guo, Guiping Feng, Xuerui Wu, and Guoping Gao Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-232,2016 Manuscript under review for AMT (discussion: open, 0 comments) Air temperature is one of the most important parameters used for monitoring Arctic climate change. The Constellation Observing System for Meteorology, Ionosphere, and Climate and Formosa Satellite mission 3 (COSMIC/FORMOSAT-3) radio occultation (RO) "wet" temperature product (i.e., "wetPrf") was introduced to analyze the Arctic air temperature profiles at 925–200 hPa in 2007–2012. The "wet" temperatures were further compared with radiosonde (RS) observations. Results from the spatially and temporally synchronized RS and COSMIC observations showed that their temperatures were matched well with each other, especially at 400 hPa. Comparisons of seasonal temperatures and anomalies from COSMIC and homogenized RS observations suggested the limited number of COSMIC observations during the spatial matchup may be insufficient to describe the small-scale spatial structure of temperature variations. Furthermore, comparisons of seasonal temperature anomalies from RS and 5 × 5 degree gridded COSMIC observations at 400 hPa during the sea ice minimum (SIM) of 2007 and 2012 were also made. Results revealed that the widely covered COSMIC observations can provide more details than RS observations in describing the Arctic temperature variations. Therefore, despite COSMIC observations being unsuitable to describe the Arctic temperatures in the lowest level, they provide a complementary data source to study the Arctic upper-air temperature variations and related climate change.

Beschreibung: Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system Juan Li and Guiqing Liu Atmos. Meas. Tech., 9, 3095-3113, doi:10.5194/amt-9-3095-2016, 2016 FengYun-3C is an operational polar-orbiting satellite carrying the new-generation microwave sounding instruments in China. It can contribute to the Global Environmental Observing System of Systems. It is anticipated that the data can be useful for the weather forecast. After quality control, the data are put into the Chinese numerical weather prediction (NWP) system. It shows that the microwave temperature observations can have a neutral to positive impact on the NWP system.

Beschreibung: Simultaneous calibration of hydrological models in geographical space András Bárdossy, Yingchun Huang, and Thorsten Wagener Hydrol. Earth Syst. Sci., 20, 2913-2928, doi:10.5194/hess-20-2913-2016, 2016 This paper explores the simultaneous calibration method to transfer model parameters from gauged to ungauged catchments. It is hypothesized that the model parameters can be separated into two categories: one reflecting the dynamic behavior and the other representing the long-term water balance. The results of three numerical experiments indicate that a good parameter transfer to ungauged catchments can be achieved through simultaneous calibration of models for a number of catchments.

Beschreibung: Characterization of anthropogenic methane plumes with the Hyperspectral Thermal Emission Spectrometer (HyTES): a retrieval method and error analysis Le Kuai, John R. Worden, King-Fai Li, Glynn C. Hulley, Francesca M. Hopkins, Charles E. Miller, Simon J. Hook, Riley M. Duren, and Andrew D. Aubrey Atmos. Meas. Tech., 9, 3165-3173, doi:10.5194/amt-9-3165-2016, 2016 This paper describes the retrieval algorithm to estimate the lower tropospheric methane concentrations using Hyperspectral Thermal Emission Spectrometer (HyTES) airborne measurements. This project aims to map and detect methane plumes from the oil leaking or dairy emission. Our results demonstrate an example of the quantitative retrievals, imaged a big methane plume from storage tanks near Kern River Oil Field. The methane enhancement is well above the uncertainties of the estimates.

Beschreibung: Improved analysis of solar signals for differential reflectivity monitoring Asko Huuskonen, Mikko Kurri, and Iwan Holleman Atmos. Meas. Tech., 9, 3183-3192, doi:10.5194/amt-9-3183-2016, 2016 The method for the daily monitoring of the differential reflectivity bias for polarimetric weather radars is developed further. Improved quality control is applied to the solar signals detected during the operational scanning of the radar, which efficiently removes rain and clutter-contaminated gates occurring in the solar hits. The simultaneous reflectivity data are used as a proxy to determine which data points are to be removed. A number of analysis methods to determine the differential reflectivity bias are compared, and methods based on surface fitting are found superior to simple averaging. A separate fit to the reflectivity of the horizontal and vertical polarization channels is recommended because of stability. Separate fitting also provides, in addition to the differential reflectivity bias, the pointing difference of the polarization channels. Data from the Finnish weather radar network show that the pointing difference is less than 0.02° and that the differential reflectivity bias is stable and determined to better than 0.04 dB. The results are compared to those from measurements at vertical incidence, which allows us to determine the total differential reflectivity bias including the differential receiver bias and the transmitter bias.

Beschreibung: Morphological dynamics of an englacial channel Geir Vatne and Tristram D. L. Irvine-Fynn Hydrol. Earth Syst. Sci., 20, 2947-2964, doi:10.5194/hess-20-2947-2016, 2016 Ten years of direct observations of an englacial conduit in a cold based glacier in Svalbard document for the first time how a vertical meltwater waterfall (moulin) is formed from gradual incision of a meltwater channel. This evolution appears to be dominated by knickpoints that incise upstream at rates several times faster than the vertical incision in adjacent near horizontal channel sections.

Beschreibung: A practical approach to lake water density from electrical conductivity and temperature Santiago Moreira, Martin Schultze, Karsten Rahn, and Bertram Boehrer Hydrol. Earth Syst. Sci., 20, 2975-2986, doi:10.5194/hess-20-2975-2016, 2016 Density calculations in lakes are essential in the study of stability, stratification and numerical modelling. However, density equations which use fixed constant coefficients are still common in use, despite their limitations. We present a practical approach which can specifically include the effect of dissolved substances by fitting two coefficients. The method has been tested against density equations and density measurements in lakes.

Beschreibung: Improving estimates of water resources in a semi-arid region by assimilating GRACE data into the PCR-GLOBWB hydrological model N. Tangdamrongsub, S. C. Steele-Dunne, B. C. Gunter, P. G. Ditmar, E. H. Sutanudjaja, Y. Sun, T. Xia, and Z. Wang Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-354,2016 Manuscript under review for HESS (discussion: open, 0 comments) An accurate estimation of water resources dynamics is crucial for proper management of both agriculture and the local ecology, particularly in semi-arid regions. Imperfections in model physics, uncertainties in model land parameters and meteorological data, as well as the human impact on land changes often limit the accuracy of hydrological models in estimating water storages. To mitigate this problem, this study investigated the assimilation of Terrestrial Water Storage (TWS) estimates derived from the Gravity Recovery And Climate Experiment (GRACE) data using an Ensemble Kalman Filter (EnKF) approach. The region considered was the Hexi Corridor of Northern China. The hydrological model used for the analysis was PCR-GLOBWB, driven by satellite-based forcing data from April 2002 to December 2010. In this study, EnKF 3D scheme, which accounts for the GRACE spatially-correlated errors, was used. The correlated errors were propagated from the full error variance-covariance matrices provided as a part of the GRACE data product. The impact of the GRACE Data Assimilation (DA) scheme was evaluated in terms of the TWS, as well as individual hydrological storage estimates. The capability of GRACE DA to adjust the storage level was apparent not only for the entire TWS but also for the groundwater component, which had annual amplitude, phase, and long-term trend estimates closer to the GRACE observations. This study also assessed the benefits of taking into account correlations of errors in GRACE-based estimates. The assessment was carried out by comparing the EnKF results, with and without taking into account error correlations, with the in situ groundwater data from 5 well sites and the in situ streamflow data from two river gauges. On average, the experiments showed that GRACE DA improved the accuracy of groundwater storage estimates by as much as 25 %. The inclusion of error correlations provided an equal or greater improvement in the estimates. No significant benefits of GRACE DA were observed in terms of streamflow estimates, which reflect a limited spatial and temporal resolution of GRACE observations. Results from the 9-year long GRACE DA study were used to assess the status of water resources over the Hexi Corridor. Areally-averaged values revealed that TWS, soil moisture, and groundwater storages over the region decreased with an average rate of approximately 0.2, 0.1, and 0.1 cm/yr in terms of equivalent water heights, respectively. A substantial decline in TWS (approximately −0.4 cm/yr) was seen over the Shiyang River Basin in particular, and the reduction mostly occurred in the groundwater layer. An investigation of the relationship between water resources and agriculture suggested that groundwater consumption required to maintain the growing period in this specific basin was likely the cause of the groundwater depletion.

Beschreibung: Monitoring surface water quality using social media in the context of citizen science Hang Zheng, Hong Yang, Di Long, and Hua Jing Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-359,2016 Manuscript under review for HESS (discussion: open, 0 comments) Do you feel angry if the river in your living place is polluted by industries? Do you want to do something to save your environment? Just log in http://www.thuhjjc.com and use the Tsinghua Environment Monitoring Platform (TEMP) to photograph the water pollution actives and make your report. This study established a social media platform to monitor and report surface water quality. The effectiveness of the platform was demonstrated by the 265 water quality reports across 29 provinces in China.

Beschreibung: Ion mobility spectrometry–mass spectrometry (IMS–MS) for on- and offline analysis of atmospheric gas and aerosol species Jordan E. Krechmer, Michael Groessl, Xuan Zhang, Heikki Junninen, Paola Massoli, Andrew T. Lambe, Joel R. Kimmel, Michael J. Cubison, Stephan Graf, Ying-Hsuan Lin, Sri H. Budisulistiorini, Haofei Zhang, Jason D. Surratt, Richard Knochenmuss, John T. Jayne, Douglas R. Worsnop, Jose-Luis Jimenez, and Manjula R. Canagaratna Atmos. Meas. Tech., 9, 3245-3262, doi:10.5194/amt-9-3245-2016, 2016 Measurement techniques that provide molecular-level information are needed to elucidate the multiphase processes that produce secondary organic aerosol (SOA) species in the atmosphere. Here we demonstrate the application of ion mobility spectrometry-mass spectrometry (IMS–MS) to the simultaneous characterization of the elemental composition and molecular structures of organic species in the gas and particulate phases. Molecular ions of gas-phase organic species are measured online with IMS–MS after ionization with a custom-built nitrate chemical ionization (CI) source. This CI–IMS–MS technique is used to obtain time-resolved measurements (5 min) of highly oxidized organic molecules during the 2013 Southern Oxidant and Aerosol Study (SOAS) ambient field campaign in the forested SE US. The ambient IMS–MS signals are consistent with laboratory IMS–MS spectra obtained from single-component carboxylic acids and multicomponent mixtures of isoprene and monoterpene oxidation products. Mass-mobility correlations in the 2-D IMS–MS space provide a means of identifying ions with similar molecular structures within complex mass spectra and are used to separate and identify monoterpene oxidation products in the ambient data that are produced from different chemical pathways. Water-soluble organic carbon (WSOC) constituents of fine aerosol particles that are not resolvable with standard analytical separation methods, such as liquid chromatography (LC), are shown to be separable with IMS–MS coupled to an electrospray ionization (ESI) source. The capability to use ion mobility to differentiate between isomers is demonstrated for organosulfates derived from the reactive uptake of isomers of isoprene epoxydiols (IEPOX) onto wet acidic sulfate aerosol. Controlled fragmentation of precursor ions by collisionally induced dissociation (CID) in the transfer region between the IMS and the MS is used to validate MS peak assignments, elucidate structures of oligomers, and confirm the presence of the organosulfate functional group.

Beschreibung: A surface reflectance scheme for retrieving aerosol optical depth over urban surfaces in MODIS Dark Target retrieval algorithm Pawan Gupta, Robert C. Levy, Shana Mattoo, Lorraine A. Remer, and Leigh A. Munchak Atmos. Meas. Tech., 9, 3293-3308, doi:10.5194/amt-9-3293-2016, 2016 A new surface scheme inside MODIS dark target aerosol retrieval algorithm has been developed to improve the accuracy of aerosol optical depth data over cities. The new scheme integrates the MODIS land surface reflectance and land cover type information into the surface parameterization for urban areas, much of the issues associated with the standard algorithm have been mitigated for our test region. The improved aerosols data sets will be useful for air quality applications over cities.

Beschreibung: Identifying water deficit and vegetation response during the 2009/10 drought over North China: Implications for the South-to-North Water Diversion project Bowen Zhu, Xianhong Xie, and Kang Zhang Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-313,2016 Manuscript under review for HESS (discussion: open, 0 comments) This study attempts to identify water deficit using GRACE data and vegetation response during the 2009/10 drought over North China. There was a decling trend in total water storage for the past decade based on GRACE data, and the regional deficit of water storage was approximately 25 km 3 in 2009/10. This drought event has led to suppression of vegetation growth in North China. The SNWD project may ease the water storage deficit in North China for this level of drought intensity.

Beschreibung: The Budyko functions under non-steady state conditions: new approach and comparison with previous formulations Roger Moussa and Jean-Paul Lhomme Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-379,2016 Manuscript under review for HESS (discussion: open, 0 comments) This paper presents a new approach to transform any Budyko function under steady-state conditions into a function valid for non-steady state conditions. It involves an additional parameter which accounts for change in soil water storage. Compared to previous formulations it gives similar results as the analytical solution of Greve et al. (2016). However, the domain of variation of the new formulation differs from those of Chen et al. (2013) and Du et al. (2016).

Beschreibung: Tropical tropospheric ozone columns from nadir retrievals of GOME-1/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A (1996–2012) Elpida Leventidou, Kai-Uwe Eichmann, Mark Weber, and John P. Burrows Atmos. Meas. Tech., 9, 3407-3427, doi:10.5194/amt-9-3407-2016, 2016 Here, we present a 17 years tropical tropospheric ozone columns dataset (1996–2012) using GOME, SCIAMACHY, and GOME-2 data, developed as part of the verification algorithm for TROPOMI on S5p mission.The uncertainty is less than 2 DU. Validation with SHADOZ ozonesonde data showed biases within 5 DU and RMS errors less than 10 DU. Comparisons with tropospheric ozone columns derived from limb–nadir matching showed that the bias and RMS are within the range of the CCD_IUP comparison with the sondes.

Beschreibung: Comparison of aerosol properties retrieved using GARRLiC, LIRIC, and Raman algorithms applied to multi-wavelength lidar and sun/sky-photometer data Valentyn Bovchaliuk, Philippe Goloub, Thierry Podvin, Igor Veselovskii, Didier Tanre, Anatoli Chaikovsky, Oleg Dubovik, Augustin Mortier, Anton Lopatin, Mikhail Korenskiy, and Stephane Victori Atmos. Meas. Tech., 9, 3391-3405, doi:10.5194/amt-9-3391-2016, 2016 Aerosol particles are important and highly variable components of the terrestrial atmosphere, and they affect both air quality and climate. In order to evaluate their multiple impacts, the most important requirement is to precisely measure their characteristics. Remote sensing technologies such as lidar (light detection and ranging) and sun/sky photometers are powerful tools for determining aerosol optical and microphysical properties. In our work, we applied several methods to joint or separate lidar and sun/sky-photometer data to retrieve aerosol properties. The Raman technique and inversion with regularization use only lidar data. The LIRIC (LIdar-Radiometer Inversion Code) and recently developed GARRLiC (Generalized Aerosol Retrieval from Radiometer and Lidar Combined data) inversion methods use joint lidar and sun/sky-photometer data. This paper presents a comparison and discussion of aerosol optical properties (extinction coefficient profiles and lidar ratios) and microphysical properties (volume concentrations, complex refractive index values, and effective radius values) retrieved using the aforementioned methods. The comparison showed inconsistencies in the retrieved lidar ratios. However, other aerosol properties were found to be generally in close agreement with the AERONET (AErosol RObotic NETwork) products. In future studies, more cases should be analysed in order to clearly define the peculiarities in our results.

Beschreibung: Characterisation and improvement of j (O 1 D) filter radiometers Birger Bohn, Dwayne E. Heard, Nikolaos Mihalopoulos, Christian Plass-Dülmer, Rainer Schmitt, and Lisa K. Whalley Atmos. Meas. Tech., 9, 3455-3466, doi:10.5194/amt-9-3455-2016, 2016 Filter radiometers are instruments that quantify the rate of formation of excited oxygen atoms from photolysis of ozone in the atmosphere. The excited oxygen atoms are important for the atmospheric self-cleaning ability. The radiometers were characterised by measurements of their spectral response. Together with field comparisons with a reference instrument, the characterisations improved the performance. That will help to better understand atmospheric photochemistry in future research.

Beschreibung: Effect of restoration vegetation on the stochasticity of soil erosion in a semi-arid environment Ji Zhou, Bojie Fu, Guangyao Gao, Yihe Lü, and Shuai Wang Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-386,2016 Manuscript under review for HESS (discussion: open, 0 comments) By monitoring soil erosion in the Loess Plateau, we constructed an integrated analysis system to quantify the stochasticity of environment, found that the morphological structures in vegetation types are the source of different stochasticities of soil erosion, and proved that Poisson model is fit for predicting erosion stochasticity at larger temporal scale. This study could be meaningful for the selection of restoration vegetation for conserving soil and water resources in the Loess Plateau.

Beschreibung: Assessing land–ocean connectivity via submarine groundwater discharge (SGD) in the Ria Formosa Lagoon (Portugal): combining radon measurements and stable isotope hydrology Carlos Rocha, Cristina Veiga-Pires, Jan Scholten, Kay Knoeller, Darren R. Gröcke, Liliana Carvalho, Jaime Anibal, and Jean Wilson Hydrol. Earth Syst. Sci., 20, 3077-3098, doi:10.5194/hess-20-3077-2016, 2016 We combine radon and stable isotopes in water to determine total submarine groundwater discharge (SGD) in the Ria Formosa and discriminate its component modes. We show that tidal action filters the entire water volume in the lagoon through local beaches 3.5 times a year, driving an estimated 350Ton nitrogen/year into the system. Conversely, fresh groundwater is discharged into the lagoon only occasionally, adding ~ 61 Ton nitrogen/year, but is capable of driving new production in the system.

Beschreibung: Variation of soil hydraulic properties with alpine grassland degradation in the Eastern Tibetan Plateau Tao Pan, Shuai Hou, Shaohong Wu, Yanhua Liu, Xintong Zou, Anna Herzberger, and Jianguo Liu Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-333,2016 Manuscript under review for HESS (discussion: open, 0 comments) The study show that soil hydraulic properties, especially those of the top soil, varied greatly with alpine swamp meadow degradation. Soil porosity is the dominant influencing factor of soil hydraulic properties. The results suggest that alpine swamp meadow degradation would inevitably lead to negative hydrological effects. Hydrological modelling in Tibetan Plateau and similar regions are recommended to understand the effects of degradation on soil hydraulic properties.

Beschreibung: Contrasting transit times of water from peatlands and eucalypt forests in the Australian Alps determined by tritium: implications for vulnerability and the source of water in upland catchments I. Cartwright and U. Morgenstern Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-361,2016 Manuscript under review for HESS (discussion: open, 0 comments) This research determines timescales over which water is stored in peatlands and adjacent eucalyptus forest catchments in upland river systems in southeast Australia using tritium. The mean transit times in the peatland catchments were in many cases less than one year which contrasts with the longer transit times (years to decades) in the eucalyptus catchments. The results indicate that the peat is susceptible to drying which renders it vulnerable to degradation and bushfire.

Beschreibung: Acclimatizing Fast Orthogonal Search (FOS) Model for River Stream-flow Forecasting Abdalla Osman, Mohammed Falah Allawi, Haitham Abdulmohsin Afan, Aboelmagd Noureldin, and Ahmed El-shafie Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-347,2016 Manuscript under review for HESS (discussion: open, 0 comments) The current research is significant not only for researchers but also for decision-makers for water resources system management more specifically for dam and reservoir operations. Fast Orthogonal Search (FOS) model might result in a system that could be used in several river basins. Supported by efficient FOS-based pattern recognition model, accurate information about future river stream flow could be utilized by the decision-maker to formulate better water resources system management.

Beschreibung: Using paraxial approximation to describe the optical setup of a typical EARLINET lidar system Panagiotis Kokkalis Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-230,2016 Manuscript under review for AMT (discussion: open, 0 comments) The mathematical formulation for the optical setup of a typical EARLINET lidar system is given here. The equations describing a lidar system from the emitted laser beam to its projection on the final receiving unit are revealed, based on paraxial approximation and geometric optics approach. The evaluation of the formulation is performed with ray tracing simulations, revealing an overall good performance with relative differences of the order of 5 % mainly attributed to aberrations that are not taken into account in paraxial approximation.

Beschreibung: Performance of post-processing algorithms for rainfall intensity measurements of tipping-bucket rain gauges Mattia Stagnaro, Matteo Colli, Luca Giovanni Lanza, and Pak Wai Chan Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-257,2016 Manuscript under review for AMT (discussion: open, 0 comments) The research presented in this work involves field data analysis, numerical modelling techniques and approaches to a long-standing problem of liquid precipitation measurements: the sampling and the interpretation of the tipping bucket sensors signal. The present study shows relevant implications of the adopted data processing methods on the accuracy of the rainfall intensity measurements provided by traditional tipping bucket gauges.

Beschreibung: GFIT2: an experimental algorithm for vertical profile retrieval from near-IR spectra Brian J. Connor, Vanessa Sherlock, Geoff Toon, Debra Wunch, and Paul O. Wennberg Atmos. Meas. Tech., 9, 3513-3525, doi:10.5194/amt-9-3513-2016, 2016 An algorithm for retrieval of vertical profiles of CO 2 from ground-based spectra is described. Retrieval of CO 2 vertical profiles from would be very beneficial for carbon cycle studies and the validation of satellite measurements. There are approximately 3 degrees of freedom for the CO 2 profile. The accuracy of retrievals of CO 2 from the spectral band used is limited by small errors in the calculated spectrum. Ongoing research is needed and described.

Beschreibung: Willingness-to-pay for a probabilistic flood forecast: a risk-based decision-making game Louise Arnal, Maria-Helena Ramos, Erin Coughlan de Perez, Hannah Louise Cloke, Elisabeth Stephens, Fredrik Wetterhall, Schalk Jan van Andel, and Florian Pappenberger Hydrol. Earth Syst. Sci., 20, 3109-3128, doi:10.5194/hess-20-3109-2016, 2016 Forecasts are produced as probabilities of occurrence of specific events, which is both an added value and a challenge for users. This paper presents a game on flood protection, "How much are you prepared to pay for a forecast?", which investigated how users perceive the value of forecasts and are willing to pay for them when making decisions. It shows that users are mainly influenced by the perceived quality of the forecasts, their need for the information and their degree of risk tolerance.

Beschreibung: Real-time monitoring of nitrate transport in the deep vadose zone under a crop field – implications for groundwater protection Tuvia Turkeltaub, Daniel Kurtzman, and Ofer Dahan Hydrol. Earth Syst. Sci., 20, 3099-3108, doi:10.5194/hess-20-3099-2016, 2016 Efficient groundwater protection from pollution originating in agriculture requires effective monitoring means capable of tacking pollution processes in the vadose zone, long before groundwater pollution turns into an unavoidable fact. In this study, a vadose zone monitoring system that was installed under a crop field fertilized by dairy slurry enabled real-time tracking of nitrate plum migration down the vadose zone from the land surface to the water table at 18m depth.

Beschreibung: How big is an OMI pixel? Martin de Graaf, Holger Sihler, Lieuwe G. Tilstra, and Piet Stammes Atmos. Meas. Tech., 9, 3607-3618, doi:10.5194/amt-9-3607-2016, 2016 The shapes and sizes of the FoV from the OMI satellite instrument were determined with extensive lab tests but never verified after launch. Here, collocated measurements from MODIS, flying in formation, were used to find the most optimal shape of the OMI FoV. This shape is not quadrangular, as suggested by the provided corner coordinates of a pixel, but rather super-Gaussian shaped and overlapping with the FoV of neighbouring pixels.

Beschreibung: Fresh groundwater resources in a large sand replenishment Sebastian Huizer, Gualbert H. P. Oude Essink, and Marc F. P. Bierkens Hydrol. Earth Syst. Sci., 20, 3149-3166, doi:10.5194/hess-20-3149-2016, 2016 The anticipation of sea-level rise has led to an innovative project called the Sand Engine, where a large volume of sand was placed on the Dutch coast. The intention is that the sand is redistributed by wind, current and tide, reinforcing coastal defence structures. Model simulations show that this large sand replenishment can result in a substantial growth of fresh groundwater resources. Thus, sand replenishments could combine coastal protection with an increase of fresh groundwater resources.

Beschreibung: CFSv2-based sub-seasonal precipitation and temperature forecast skill over the contiguous United States Di Tian, Eric F. Wood, and Xing Yuan Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-376,2016 Manuscript under review for HESS (discussion: open, 0 comments) Forecasts from global seasonal climate forecast models can be potentially exploited for sub-seasonal forecasts of precipitation and 2-m temperature. The probabilistic sub-seasonal forecast skill of ten precipitation and temperature indices is investigated using the 28-years’ hindcasts of the Climate Forecast System version 2 (CFSv2) over the contiguous United States (CONUS). The forecast skill is highly dependent on the forecast indices, regions, seasons, leads, and methods. Indices characterizing mean precipitation and temperature as well as measuring frequency or duration of precipitation and temperature extremes for 7-, 14-, and 30-day forecasts were skillful depending on seasons, regions, and forecast leads. Forecasts for 7- and 14-day temperature indices showed skill even at weeks 3 and 4, and generally more skillful than precipitation indices. Overall, temperature indices showed higher skill than precipitation indices over the entire CONUS region. While the forecast skill related to mean precipitation indices were low in summer over the CONUS, the number of rainy days, number of consecutive rainy days, and the number of consecutive dry days showed considerable high skill for the west coast region. The 30-day forecasts of precipitation and temperature indices calculated from the downscaled monthly CFSv2 forecasts are less skillful than those calculated from the daily CFSv2 forecasts, suggesting the potential usefulness of the CFSv2 daily forecasts for hydrological applications relative to the temporally disaggregated CFSv2 monthly forecasts. While the presence of active Madden-Julian Oscillation (MJO) events improves CFSv2 weekly mean precipitation forecast skill over major areas of CONUS, MJO or El Niño Southern Oscillation did not have same strong effects on weekly mean temperature forecasts.

Beschreibung: Gauge-Adjusted Rainfall Estimates from Commercial Microwave Links Martin Fencl, Michal Dohnal, Jörg Rieckermann, and Vojtěch Bareš Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-397,2016 Manuscript under review for HESS (discussion: open, 0 comments) Commercial microwave links (CMLs) can provide rainfall observations with high space-time resolution. Unfortunately, CML rainfall estimates are usually biased because we lack detailed information on the processes which attenuate the transmitted microwaves. We suggest removing the bias by dynamically adjusting CMLs to cumulative data from rain gauges (RGs), which can be remote from the CMLs. Our approach practically eliminates the bias, which we demonstrate on unique data from several CMLs a RGs.

Beschreibung: A strategy for the measurement of the CO 2 distribution in the stratosphere Massimo Carlotti, Bianca Maria Dinelli, Giada Innocenti, and Luca Palchetti Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-220,2016 Manuscript under review for AMT (discussion: open, 0 comments) We introduce a strategy for the measurement of CO 2 in the stratosphere. We use an orbiting limb sounder to measure both the Thermal InfraRed (TIR) and Far-InfraRed (FIR) atmospheric emission. The rotational transitions of O 2 in the FIR are exploited to derive the temperature and pressure fields that are needed to retrieve the CO 2 from its spectrum in the TIR. The proposed experiment can determine two-dimensional distributions of the CO 2 with accuracy of 1 ppm at altitudes between 10 and 50 km.

Beschreibung: Smithsonian Astrophysical Observatory Ozone Mapping and Profiler Suite (SAO OMPS) formaldehyde retrieval Gonzalo González Abad, Alexander Vasilkov, Colin Seftor, Xiong Liu, and Kelly Chance Atmos. Meas. Tech., 9, 2797-2812, doi:10.5194/amt-9-2797-2016, 2016 The multi-spectral possibilities of the OMPS Nadir Mapper instrument are exploited here to perform formaldehyde retrievals. Orbiting the Earth at 824 km, OMPS observes the atmosphere in a time frame similar to instruments belonging to NASA's A-Train constellation, 01:30. We show that OMPS is well suited to measure formaldehyde despite its spectral resolution of 1nm. The comparison of OMPS retrievals with OMI products show good temporal correlation.

Beschreibung: Accomplishments of the MUSICA project to provide accurate, long-term, global and high-resolution observations of tropospheric {H 2 O, δ D} pairs – a review Matthias Schneider, Andreas Wiegele, Sabine Barthlott, Yenny González, Emanuel Christner, Christoph Dyroff, Omaira E. García, Frank Hase, Thomas Blumenstock, Eliezer Sepúlveda, Gizaw Mengistu Tsidu, Samuel Takele Kenea, Sergio Rodríguez, and Javier Andrey Atmos. Meas. Tech., 9, 2845-2875, doi:10.5194/amt-9-2845-2016, 2016 Tropospheric {H 2 O, δ D} pairs can be observed by remote sensing techniques, but the data quality strongly depends on a comprehensive consideration of the complex nature and a careful calibration of the remote sensing data pairs. This paper reviews the quality assurance/documentation activities of the MUSICA project and demonstrates that MUSICA’s ground-based FTIR and space-based IASI {H 2 O, δ D} pair products are accurate and can be generated at a global scale with high resolution and for long periods.

Beschreibung: Top-of-the-atmosphere shortwave flux estimation from satellite observations: an empirical neural network approach applied with data from the A-train constellation Pawan Gupta, Joanna Joiner, Alexander Vasilkov, and Pawan K. Bhartia Atmos. Meas. Tech., 9, 2813-2826, doi:10.5194/amt-9-2813-2016, 2016 The A-train constellation of satellites provides a unique opportunity to analyze near-simultaneous data from several of these sensors. In this paper, retrievals of cloud/aerosols parameters and total column ozone (TCO) from the Aura Ozone Monitoring Instrument (OMI) have been used to develop a variety of neural networks that estimate TOA SWF globally over ocean and land using only OMI data as inputs. Application of our method to other ultraviolet sensors may provide unique estimates of TOA SWF.

Beschreibung: Measurement of OH reactivity by laser flash photolysis coupled with laser-induced fluorescence spectroscopy Daniel Stone, Lisa K. Whalley, Trevor Ingham, Peter M. Edwards, Danny R. Cryer, Charlotte A. Brumby, Paul W. Seakins, and Dwayne E. Heard Atmos. Meas. Tech., 9, 2827-2844, doi:10.5194/amt-9-2827-2016, 2016 OH reactivity is the total pseudo-first-order loss rate coefficient describing the removal of OH radicals to all sinks in the atmosphere. Measurements of ambient OH reactivity can be used to discover the extent to which measured OH sinks contribute to the total OH loss rate. In this work, we describe the design and characterisation of an instrument to measure OH reactivity using laser flash photolysis coupled to laser-induced fluorescence (LFP-LIF) spectroscopy.

Beschreibung: Improvement of Vertical Velocity Statistics Measured by a Doppler Lidar through Comparison with Sonic Anemometer Observations Timothy A. Bonin, Jennifer F. Newman, Petra M. Klein, Phillip B. Chilson, and Sonia Wharton Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-134,2016 Manuscript under review for AMT (discussion: open, 0 comments) Turbulence measurements are important to boundary layer meteorology and related fields. Doppler lidars are capable of providing continuous profiles of turbulence statistics. Herein, the most direct turbulence measurement, vertical velocity variance, is validated with those from sonic anemometers. Spectra are also compared. A method to improve calculated velocity variance using the autocovariance is shown to improve the accuracy of the measurement by mitigating effects of noise and averaging.

Beschreibung: Assessment of the underestimation of snowfall accumulation by tipping bucket gauges used operationally by the Spanish national weather service Samuel T. Buisan, Michael E. Earle, José Luís Collado, John Kochendorfer, Javier Alastrué, Mareile Wolff, Craig D. Smith, and Juan I. López-Moreno Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-197,2016 Manuscript under review for AMT (discussion: open, 0 comments) Within the framework of the WMO-SPICE (Solid Precipitation Intercomparison Experiment) the Thies tipping bucket precipitation gauge, widely-used at AEMET, was assessed against the SPICE reference. Most countries use tipping buckets and for this reason the underestimation of snowfall precipitation is a large scale problem. The methodology presented here can be used by other national weather services to test precipitation bias corrections and to identify regions where errors are higher.