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排序方式: 共有1039条查询结果,搜索用时 15 毫秒
1.
Sea level rise threatens coastal communities throughout the United States, and South Florida is on the front line. The iconic and built-up city of Miami Beach, Florida, has a well-developed, high-value property market, and the municipality has been lauded for proactively taking action to adapt to anticipated sea level rise. Moving beyond hyperbole and piecemeal evidence, we compile a comprehensive inventory of adaptation and mitigation measures implemented by various municipal agencies. We employ these data sets to measure exposure and readiness for the entire city and make a preliminary effort to develop a city vulnerability index. Our findings reveal that exposure throughout the city is high and that readiness is concentrated near stormwater drainage systems, leading to high vulnerability along the coast. When we compare the spatial patterns of the vulnerability index and the residential property values, we find a mismatch. The most vulnerable regions are characterized by high income, transiency, and an apparent unresponsiveness to sea level rise. No doubt our findings illustrate a lag effect, but if sea level rise increases, the real estate market could reach a tipping point unless state and federal agencies also fund more comprehensive adaptation. 相似文献
2.
Roy F. Spalding Aaron J. Hirsh Mary E. Exner Marty Stange Ramon Aravena 《Ground Water Monitoring & Remediation》2019,39(2):22-31
Identification of major nitrate sources that adversely impact groundwater quality in municipal well capture zones in areas of emerging nitrate contamination is essential to minimize leaching and prevent exceedance of the nitrate drinking water standard. Vertical profiles of nitrate leachate in deep soils provide an estimate of the amount of nitrate in transit beneath irrigated, row-cropped fields; depths of peak leachate; and the approximate rate of downward movement. Profiles of pore-water soil-nitrate concentrations in thick 60-feet (~18 m), fine-textured soils near Hastings, Nebraska clearly indicate that considerably more nitrate leached beneath furrow-irrigated than center-pivot irrigated fields. Peak leaching appeared to correlate with recorded periods of poor weather conditions during some growing seasons and may best be controlled by “spoon feeding” fertilizer to the crop through the sprinkler irrigation system at times of nutrient need. The presence of trace levels of atrazine and deethylatrazine to 60 feet (18 m) in core samples indicates that larger, more complex anthropogenic molecules also leach through the fine-textured soils. The light δ15NNO3 values in the surficial groundwater beneath fertilized and irrigated cropland indicate that ammonium fertilizer is a major N source and suggest that the natural soil-N contribution is negligible. δ15NNO3 values were most enriched in irrigation wells located within municipal well capture zones downgradient of a large feedlot. Dual isotope method (DIM) δ15NNO3 and δ18ONO3 values suggest that the Hastings’ municipal wells farther downgradient are contaminated with a mixture of nitrate from manure and commercial ammonium-based fertilizer. DIM values indicate an absence of denitrification, which has implications for long-term management of the water resources. 相似文献
3.
University faculty partners from the Departments of Geography and Instruction and Teacher Education at a large, public university collaborated with K-12 teachers and the leadership of a rural school district in order to investigate the crosscutting content of science, mathematics, and geography through the integration of web-based GIS technologies. The project explored the critical connections among technology, pedagogy, and content with a particular emphasis on developing technology-enhanced, inquiry-based lessons in which the teachers and their students used GIS technologies to analyze, visualize, and present data in real-world contexts. The findings highlight the importance of well-structured professional development that builds community, integrates diverse content and pedagogical expertise, provides feedback and coaching, and is of sufficient duration to effect change. 相似文献
4.
Roy R. Kuttippurath J. Lefèvre F. Raj S. Kumar P. 《Theoretical and Applied Climatology》2022,149(1-2):119-130
Theoretical and Applied Climatology - Sudden stratospheric warmings (SSWs) are associated with rapid rise in temperature in a short period of time in the polar vortex and reversal of the zonal... 相似文献
5.
T. P. S. Rawat Madhuparna Roy G. B. Joshi 《Journal of the Geological Society of India》2018,91(1):25-31
Sonrai basin, located along the southwestern margin of Bundelkhand Granite-Gneiss Complex (BGC) is known for its base metal and phosphorite mineralization. Uranium mineralization of appreciable grade and thickness was reported in Pisnari block in the northern part of this basin during sub-surface exploration activity in 1976-97. This was in the form of uranium-bitumin association within fractures in the carbonate-terrigenous sediments of Gorakalan shale, Rohini carbonate and Bandai sandstone of Sonrai Formation of Bijawar Group. Similar mineralization was also noted within the lower chloritic shale member of Solda Formation of the same Group. During subsequent drilling activity at a later phase (2005-09), uranium rich zones within Rohini carbonate and chloritic shale members were corroborated by the interception of mineralized bands in two boreholes drilled near Pisnari. Petrographic study of radioactive core samples reveal that uranium mineralization is closely associated with globular carbonaceous matter and sulphides along the fractures. Uranium is either adsorbed in carbonaceous matter or occurs as ultrafine inclusions of coffinite within carbonaceous matter. An additional phase of secondary uranium mineral (uranophane) is also noted in one of the boreholes. The uranium minerals, in association with sulphides, fill up moderately dipping fractures (approximately 15o towards North) which are oblique to the core axis of the inclined borehole and thus, the mineralization is characterized as hydrothermal fracture-controlled vein type mineralisation. C-HN- S analysis of carbonaceous matter occurring in close association with the uranium minerals reveal heterogeneity in composition with respect to carbon and sulfur. The present paper aims at discussing the geological, petrological and radiometric aspects of this mineralization, so as to enhance the understanding of the same. 相似文献
6.
Nikhil Ghodichore R Vinnarasi C T Dhanya Somnath Baidya Roy 《Journal of Earth System Science》2018,127(8):115
Various reanalyses have been utilized in numerous climate related researches around the globe, however, there exists considerable biasedness in these products, especially in precipitation and temperature data. The ability of these reanalysis products to simulate the precipitation and temperature patterns is observed to be satisfactory at global scale, while it differs significantly at regional scale, especially over regions of high spatio-temporal heterogeneity such as India. Therefore, it is essential to evaluate the applicability and robustness of reanalyses in climate related research. The annual and seasonal variability in spatio-temporal patterns and trends of precipitation and temperature data, with respect to the IMD gridded data over 34 yrs, are evaluated for six global reanalyses namely, NCEP/NCAR Reanalysis (NCEP R1), NCEP-DOE AMIP-2 Reanalysis (NCEP R2), Climate Forecast System Reanalysis (CFSR), ECMWF Interim Reanalysis (ERA-Interim), Modern Era Retrospective Analysis for Research and Application Land only model (MERRA-Land) and JMA 55-year Reanalysis (JRA-55). The ability of the reanalyses was tested based on several factors such as statistical and categorical indices, spells and trends, for annual and seasonal daily values. Several regional and seasonal differences were observed, particularly over high rainfall regions such as Western Ghats and northeastern India. MERRA-Land is found to give the best results for precipitation over India, which is attributed to the updated forcing data using gauge-based precipitation observations. Similarly, ERA-Interim and JRA-55 exhibit better performance for temperature than other datasets. All reanalyses failed to correctly reproduce the trends in IMD data, for both precipitation and temperature. These observations will provide a better perception on the reliability and applicability of reanalyses for climate and hydrological studies over India. 相似文献
7.
Roy T. Churchwell Steve Kendall Stephen C. Brown Arny L. Blanchard Tuula E. Hollmen Abby N. Powell 《Estuaries and Coasts》2018,41(1):280-292
River deltas along Alaska’s Beaufort Sea coast are used by hatch-year semipalmated sandpipers (Calidris pusilla) after leaving their terrestrial natal sites, but the drivers of their use of these stopover sites on the first “hop” of fall migration are unknown. We quantified sandpiper temporal distribution and abundance as related to food resources at three river deltas during the beginning of their fall migration (post-breeding period) to compare the habitat quality among these deltas. We conducted population counts, sampled invertebrates, and captured birds to collect blood samples from individuals for triglyceride and stable isotope analyses to determine fattening rates and diet. Patterns of sandpiper and invertebrate abundance were complex and varied among deltas and within seasons. River deltas were used by sandpipers from late July to late August, and peak sandpiper counts ranged from 1000 to 4000 individuals, of which 98% were hatch-year semipalmated sandpipers. Isotopic signatures from blood plasma samples indicated that birds switched from a diet of upland tundra to delta invertebrate taxa as the migration season progressed, suggesting a dependence on delta invertebrates. Despite differences in diet among deltas, we found no differences in fattening rates of juvenile sandpipers as indicated by triglyceride levels. The number of sandpipers was positively associated with abundance of Amphipoda and Oligochaeta at the Jago and Okpilak-Hulahula deltas; an isotopic mixing model indicated that sandpipers consumed Amphipoda and Oligochaeta at Jago, mostly Chironomidae at Okpilak-Hulahula and Spionidae at Canning. Regardless of the difference in sandpiper diets at the Beaufort Sea deltas, their similar fattening rates throughout the season indicate that all of these stopover sites provide a critical food resource for hatch-year sandpipers beginning their first migration. 相似文献
8.
Roy James W. Bordeleau Genevive Rivard Christine Ryan M. Cathryn Malet Xavier Brown Susan J. Tremblay Vincent 《Hydrogeology Journal》2022,30(3):1005-1019
Hydrogeology Journal - Monitoring of dissolved methane concentrations in groundwater is required to identify impacts from oil and gas development and to understand temporal variability under... 相似文献
9.
10.
T. Roy Choudhury Kanan Datta Suman Majumdar Raghunath Ghara Aseem Paranjape Rajesh Mondal Somnath Bharadwaj Saumyadip Samui 《Journal of Astrophysics and Astronomy》2016,37(4):29
Studying the cosmic dawn and the epoch of reionization through the redshifted 21-cm line are among the major science goals of the SKA1. Their significance lies in the fact that they are closely related to the very first stars in the Universe. Interpreting the upcoming data would require detailed modelling of the relevant physical processes. In this article, we focus on the theoretical models of reionization that have been worked out by various groups working in India with the upcoming SKA in mind. These models include purely analytical and semi-numerical calculations as well as fully numerical radiative transfer simulations. The predictions of the 21-cm signal from these models would be useful in constraining the properties of the early galaxies using the SKA data. 相似文献