ALBERT

Description: Langmuir DOI: 10.1021/la4030348

Description: Langmuir DOI: 10.1021/la4031848

Description: Coal fires that are induced by natural spontaneous combustion or result from human activities occurring on the surface and in underground coal seams destroy coal resources and cause serious environmental degradation. Thermal infrared image data, which directly measure surface temperature, can be an important tool to map coal fires over large areas. As the first of two parts introducing our coal fire detection method, this paper proposes a self-adaptive threshold-based approach for coal fire detection using ASTER thermal infrared data: the self-adaptive gradient-based thresholding method (SAGBT). This method is based on an assumption that the attenuation of temperature along the coal fire’s boundaries generates considerable numbers of spots with extremely high gradient values. The SAGBT method applied mathematical morphology thinning to skeletonize the potential high gradient buffers into the extremely high gradient lines, which provides a self-adaptive mechanism to generate thresholds according to the thermal spatial patterns of the images. The final threshold was defined as an average temperature value reading from the high temperature buffers (segmented by 1.0 σ from the mean) and along a sequence of extremely high gradient lines (thinned from the potential high gradient buffers and segmented within the lower bounds, ranging from 0.5 σ to 1.5 σ and with an upper bound of 3.2 σ, where σ is the standard deviation), marking the coal fire areas. The SAGBT method used the basic outer boundary of the coal-bearing strata to simply exclude false alarms. The intermediate thresholds reduced the coupling with the temperature and converged by changing the potential high gradient buffers. This simple approach can be economical and accurate in identifying coal fire areas. In addition, it allows for the identification of thresholds using multiple ASTER TIR scenes in a consistent and uniform manner, and supports long-term coal fire change analyses using historical images in local areas. This paper focuses on the introduction of the methodology. Furthermore, an improvement to SAGBT is proposed. In a subsequent paper, subtitled “Part 2, Validation and Sensitivity Analysis,” we address satellite-field simultaneous observations and report comparisons between the retrieved thermal anomalies and field measurements in different aspects to prove that the coal fires are separable by the SAGBT method. These comparisons allowed us to estimate the accuracy and biases of the SAGBT method. As an application of the SAGBT, a relationship between coal fires’ decadal variation and coal production was also examined. Our work documented a total area increase in the beginning of 2003, which correlates with increased mining activities and the rapid increase of energy consumption in China during the decade (2001–2011). Additionally, a decrease in the total coal fire area is consistent with the nationally sponsored fire suppression efforts during 2007–2008. It demonstrated the applicability of SAGBT method for long-term change detection with multi-temporal images.

Description: Empirical and modelling studies show that urbanization can have an impact on the environment. Relatively few studies have investigated urban effects on precipitation in India or other developing countries experiencing rapid urbanization. Furthermore, most precipitation-related studies for India focus on monsoonal rainfall. However, premonsoonal periods (March–May) account for 12–14% of the annual cumulative rainfall in eastern India. The majority of premonsoonal rainfall (PMR) is convective and caused by mesoscale forcing, which may include urban effects. In this study, the area under scrutiny is a large urban area in eastern India, Kolkata city. Herein, our goal was to (1) produce a comprehensive characterization of historical land cover dynamics associated with the Kolkata megalopolis, (2) provide a spatio-temporal climatology of PMR in the Kolkata region, and (3) identify possible associations between Kolkata's land cover and PMR. The analysis shows that the rate of change of urban land cover has increased by 50% compared to the period prior to India's independence in 1947. A multi-scalar time series analysis with Mann–Kendall statistics indicated statistically significant increasing trends in rainfall over the last 50 years for two Kolkata stations and a nearby downwind station. Furthermore, there was no significant trend for cumulative PMR in less urbanized stations, the country of India, or the East Gangetic region. This finding suggests that the anomaly of the three stations, showing increasing trends in PMR, could be the effect of urban land cover change. Copyright © 2011 Royal Meteorological Society

Description: Langmuir DOI: 10.1021/la403278x

Description: Domestic wastewater is injected into Florida’s permeable aquifer system via Class I and Class V wells theoretically to avoid nutrient loading and other contamination that occurs when domestic wastewater is discharged directly to surface waters, resulting in nutrient loading and harmful algal blooms (HABs). The majority of Class I aquifer-injection wells are used to inject secondary-treated effluent from domestic wastewater treatment plants. Class V aquifer-injection wells also include injection of domestic wastewater. As of July 28, 2014, 257 Class I aquifer-injection wells and 14,466 Class V aquifer-injection wells had been permitted in Florida by the Florida Department of Environmental Protection (FDEP), with 34 Class I wells and 10,671 Class V wells located in the Florida Keys, Monroe County and Miami-Dade County, in southeast Florida. The presumption is that the injected wastewater will be contained within the aquifer zone where the injection is permitted and not move into overlying aquifer zones or surface waters. No large-scale monitoring in surface waters is conducted to confirm that the predominantly non-saline domestic wastewater injected into aquifer zones of higher salinities is not discharging to surface waters, such as the near-shore coastal waters in southeast Florida that provide habitat for coral reefs and federally threatened and endangered species, such as sea turtles and manatees. As an example of how such monitoring could be conducted, a case study was initiated in the coastal waters of the Florida Keys to evaluate the hypothesis that: 1) deep-aquifer (Floridan) discharges occur in localized areas of environmental decline and 2) dense benthic macroalgae associated with submarine groundwater discharges (SGD) in those localized areas, exhibit stable nitrogen isotope ratios (d 15 N) indicative of sewage effluent. Sites were selected in near-shore (continental shelf) surface waters in Biscayne Bay (vicinity of Black Point deep-aquifer sewage-effluent injection facility); Card Sound/Barnes Sound; Florida Bay (Everglades National Park); and Florida Keys ocean side (vicinity of 〉1000 primarily shallow-aquifer Class V injection wells). Dissolved helium (He) anomalies in surface waters were used as tracers of groundwater origin. Excesses of 4 He indicate deep-aquifer discharges. Greatest 4 He excesses were in the Marquesas Keys, where localized coral decline and dense benthic macroalgae occurred, and north Florida Bay, where seagrass dieoff occurred in 1987. Benthic macroalgal samples from sites with dense macroalgal growth and localized coral decline had d 15 N ratios indicative of sewage: 1) where sewage effluent disposal was concentrated in aquifer-injection wells, and 2) in the Marquesas Keys, ~40 km from the nearest shallow-aquifer injection wells, septic tanks, and cess pits. Surfacewater signatures indicative of aquifer-injection zones reconfirm breached (leaky) aquifer confinement and ocean-side Floridan-aquifer discharges for the Keys. Remote sites with deep-aquifer signatures, extensive, dense mats of benthic macroalgae, and d 15 N signatures indicative of sewage effluent suggest effluent-laden SGD via karst conduits may be a significant source of localized nutrients supporting these HABs. The locations of our georeferenced and transformed lineaments representing fractures mapped in 1973 in analog format reveal that approximately 100 fractures extend or can be extended through our study area in the coastal waters surrounding the Florida Keys. Of those fractures, 21 are associated with sites with environmental abnormalities (i.e., dense benthic macroalgae with d 15 N signatures indicative of sewage effluent; salinity; chlorophyll-a; radon excesses indicative of deep-aquifer discharges; walls of turbid water at deep coral reefs). Six of those fractures are within 1 km of aquifer-injection wells on Florida’s west coast and 15 are within 1 km of aquifer-injection wells on Florida’s east coast. The west coast injection wells include those in the following counties: Charlotte (one Class I well at one facility); Collier (four Class I wells at two facilities); and Lee (three Class I wells at two facilities). East coast injection wells include those in the following counties: Broward (21 Class I wells at nine facilities); Dade (21 Class I wells and 26 Class V wells at 7 facilities and three clusters of Class V wells); Martin (two Class I wells at one facility); Monroe (four clusters of Class V wells at multiple facilities); and Palm Beach (five Class I wells at four facilities). Depths of those Class I and Class V wells range from 668 to 928 m and 9 to 23 m, respectively. The deeper wells are within geologic formations of the Floridan aquifer system characterized by submarine sinkholes and fractures along southeastern Florida. In addition to sewage effluent, liquid waste from landfills, nuclear power plants and reverse osmosis facilities are injected into wells associated with those fractures that may be transporting those wastes by preferential flow through these fractures to resurface as SGD in near-shore coastal waters surrounding the Florida Keys and coral reefs. These results provide a framework for future research, including groundwater tracer tests in injection wells and studies focusing on the vicinity of those fractures and fracture extensions in coastal waters surrounding the Florida Keys.

Description: Langmuir DOI: 10.1021/la500937g

Description: Langmuir DOI: 10.1021/acs.langmuir.7b00142

Description: Journal of the American Chemical Society DOI: 10.1021/ja404979z

Description: The self-adaptive gradient-based thresholding (SAGBT) method is a simple non-interactive coal fire detection approach involving segmentation and a threshold identification algorithm that adapts to the spatial distribution of thermal features over a landscape. SAGBT detects coal fire using multispectral thermal images acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor. The method was detailed by our previous work “Self-Adaptive Gradient-Based Thresholding Method for Coal Fire Detection Based on ASTER Data—Part 1, Methodology”. The current study evaluates the performance of SAGBT and validates its results by using ASTER thermal infrared (TIR) images and ground temperature data collected at the Wuda coalfield (China) during satellite overpass. We further analyzed algorithm performance by using nighttime TIR images and images from different seasons. SAGBT-derived fires matched fire spots measured in the field with an average offset of 32.44 m and a matching rate of 70%–85%. Coal fire areas from TIR images generally agreed with coal-related anomalies from visible-near infrared (VNIR) images. Further, high-temperature pixels in the ASTER image matched observed coal fire areas, including the major extreme high-temperature regions derived from field samples. Finally, coal fires detected by daytime and by nighttime images were found to have similar spatial distributions, although fires differ in shape and size. Results included the stratification of our study site into two temperature groups (high and low temperature), using a fire boundary. We conclude that SAGBT can be successfully used for coal fire detection and analysis at our study site.