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21.
High resolution water body mapping for SWAT evaporative modelling in the Upper Oconee watershed of Georgia,USA 
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下载免费PDF全文 Technological improvements in remote sensing and geographic information systems have demonstrated the abundance of artificially constructed water bodies across the landscape. Although research has shown the ubiquity of small ponds globally, and in the southeastern United States in particular, their cumulative impact in terms of evaporative alteration is less well quantified. The objectives of this study are to examine the hydrologic and evaporative importance of small artificial water bodies in the Upper Oconee watershed in the northern Georgia Piedmont, USA, by mapping their locations and modelling these small reservoirs using the Soil Water Assessment Tool. Comparative Soil Water Assessment Tool models were run with and without the inclusion of small reservoir surface area and volume. The models used meteorological inputs from 1990–2013 to represent years with drought, high precipitation, and moderate precipitation for both the calibration and evaluation periods. Statistical comparison of streamflow indicated that the calibration methodology produced results where the default model simulation without reservoirs fit observed flows more closely than the modified model with small reservoirs included (e.g., Nash–Sutcliffe efficiency of 0.72 vs. 0.64, r2 of 0.73 vs. 0.66, and percent bias of 11.4 vs. 21.6). In addition, Penman–Monteith, Hargreaves, and Priestley–Taylor evapotranspiration equations were used to estimate actual evaporation from 2,219 small water bodies identified throughout the 1,936.8 km2 watershed. Depending on the evaporation equation used, water bodies evaporated an average of 0.03–0.036 km3/year for the period 2003–2013. Using Penman–Monteith further, if the reservoirs were not considered and average actual evapotranspiration rates from the rest of the basin were applied, only 0.016 km3 of water would have left the basin as a result of evapotranspiration. This finding suggests construction of small reservoirs increased evaporation by an average of 0.017 km3 per year (approximately 46,500 m3/day). As the construction of small reservoirs continues and high resolution image data used to map these water bodies becomes increasingly available, watershed models that evolve to address the cumulative impacts of small water bodies on evaporation and other hydrologic processes will have greater potential to benefit the water resource management community. 相似文献
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Groundwater, an essential resource, is likely to change with global warming because of changes in the CO2 levels, temperature and precipitation. Here, we combine water isotope geochemistry with climate modelling to examine future groundwater recharge in southwest Ohio, USA. We first establish the stable isotope profiles of oxygen and deuterium in precipitation and groundwater. We then use an isotope mass balance model to determine seasonal groundwater recharge from precipitation. Climate model output is used to project future changes in precipitation and its seasonal distribution under medium and high climate change scenarios. Finally, these results are combined to examine future changes in groundwater recharge. We find that 76% of the groundwater recharge occurs in the cool season. Climate models project precipitation increase in the cool season and decrease in the warm season. The total groundwater recharge is expected to increase by 3.2% (8.8%) under the medium (high) climate change scenarios. 相似文献
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Blackman Donna K. Abe Natsue Carlson Richard L. Guerin Gilles Ildefonse Benoit Kumpf Amber 《Marine Geophysical Researches》2019,40(4):557-569
Marine Geophysical Research - The physical properties of rock within Oceanic Core Complexes (OCC) provide information about the history of magmatism, deformation and alteration associated with... 相似文献
24.
Amber Hardison Craig Tobias Jennifer Stanhope Elizabeth Canuel Iris Anderson 《Estuaries and Coasts》2011,34(2):243-255
The water–sediment interface is a dynamic zone where the benthic and pelagic environments are linked through exchange and
recycling of organic matter and nutrients. However, it is often difficult to measure rate processes in this zone. To that
end, we designed an experimental apparatus for continuous and homogeneous perfusion of sediment porewater with dissolved conservative
(SF6, Rhodamine WT dye) and isotopic (H13CO3− and 15NH4+) tracers to study nitrogen and carbon cycling by the sediment microbial community of shallow illuminated sediments. The perfusionator
consists of a 60-cm ID × 60-cm high cylinder that includes a reservoir for porewater at the base of the sediment column. Porewater
amended with conservative and stable isotopic tracers was pumped through a mixing reservoir and upward through the overlying
sediments. We tested the perfusionator in a laboratory setting, as part of an outdoor mesocosm array, and buried in coastal
sediments. Conservative and isotopic tracers demonstrated that the porewater tracers were distributed homogeneously through
the sediment column in all settings. The perfusionator was designed to introduce dissolved stable isotope tracers but is capable
of delivering any dissolved ionic, organic, or gaseous constituent. We see a potentially wide application of this technique
in the aquatic and marine sciences in laboratory and field settings. 相似文献
25.
Geographers have long been associated with mapping and cartography, because the visual representation of space fits neatly into the wide-ranging discipline that engages both the physical and the social worlds. Mapmaking remained in the domain of experts for centuries until the advent of new mapping technologies, which have widened the possibilities for mapmaking from experts and nonexperts alike. Simply widening participation in mapmaking does not necessarily democratize the knowledge-production process, however, as scholars have recently argued. What is required, we suggest, are critically trained geographers who take seriously both the conventions of professional cartography and the power relations embedded in and reflected in the map-making process and in maps themselves. We name participatory action mapping (PAM) as a methodology that seeks to be as effective in advancing the mapping needs of the public as it is critical in evaluating the processes through which maps are produced. PAM is a practice of civic engagement that borrows from community mapping and public participatory geographic information systems and that is deeply informed by participatory action research. We highlight the contours of PAM through a case study of our work with the Westside Atlanta Land Trust in Atlanta, Georgia. 相似文献
26.
Bhaleka D. Persaud Krysha A. Dukacz Gopal C. Saha Amber Peterson Laleh Moradi Stephen O'Hearn Erin Clary Juliane Mai Michael Steeleworthy Jason J. Venkiteswaran Homa Kheyrollah Pour Brent B. Wolfe Sean K. Carey John W. Pomeroy Chris M. DeBeer James M. Waddington Philippe Van Cappellen Jimmy Lin 《水文研究》2021,35(11):e14385
Water science data are a valuable asset that both underpins the original research project and bolsters new research questions, particularly in view of the increasingly complex water issues facing Canada and the world. Whilst there is general support for making data more broadly accessible, and a number of water science journals and funding agencies have adopted policies that require researchers to share data in accordance with the findable, accessible, interoperable, reusable (FAIR) principles, there are still questions about effective management of data to protect their usefulness over time. Incorporating data management practices and standards at the outset of a water science research project will enable researchers to efficiently locate, analyse and use data throughout the project lifecycle, and will ensure the data maintain their value after the project has ended. Here, some common misconceptions about data management are highlighted, along with insights and practical advice to assist established and early career water science researchers as they integrate data management best practices and tools into their research. Freely available tools and training opportunities made available in Canada through Global Water Futures, The Gordon Foundation DataStream, the Digital Research Alliance of Canada Portage Network, Compute Canada, and university libraries, among others are compiled. These include webinars, training videos, and individual support for the water science community that together enable researchers to protect their data assets and meet the expectations of journals and funders. The perspectives shared here have been developed as part of the Global Water Futures programme's efforts to improve data management and promote the use of common data practices and standards in the context of water science in Canada. Ten best practices are proposed that may be broadly applicable to other disciplines in the natural sciences and can be adopted and adapted globally. 相似文献
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28.
Amber Murrey 《Singapore journal of tropical geography》2016,37(2):224-248
Anger, grief, regret and shame are some of the myriad ways that people narrate a decade of life along the Chad‐Cameroon Oil Pipeline. These stories reveal a perceptive and collective socio‐political awareness situated within multifaceted emotional geographies of resistance. In spite of resistance narratives, explicit and collective resistance practices remain uncommon. As people struggle and live within composite landscapes of structural violence along the pipeline, particular processes and mechanisms of uneven power influence the tendency for resistance struggles to be slow, impromptu or labour based. In this comparative ethnographic analysis, I consider the political environment that shapes socio‐political emotional ties in Nanga, particularly its socio‐political positioning as ‘the village of the First Lady’. In this case, people in proximate positions vis‐à‐vis the ruling family experience heightened oppression(s) and dispossession(s), at the same time that they report feeling little political recourse. In Kribi, on the other hand, responses to the pipeline can be described as defiant withdrawals, demonstrated through a series of unconnected refusals. Although resistance practices along the pipeline have not been visible or successful in an established sense, emotional geographies of resistance elucidate long‐term struggles to survive (i.e., slow dissent), including the accumulation of a collective emotional consciousness grounded in an awareness of historical patterns of injustice. 相似文献
29.
For epibiotic or symbiotic marine invertebrates, alternative host species may differ substantially in quality, and under some circumstances such differences in host quality may lead to the evolution of increased host specificity. However, the fitness consequences of alternative hosts for epibiotic or symbiotic marine invertebrates have rarely been quantified. In Southern California, the gastropod Crepidula onyx is often found as an epibiont on either bay mussels (Mytilus galloprovincialis) or cone snails (Conus californicus). These hosts differ greatly in maximum size, with possible effects on size at sex change and final size in Cr. onyx, and thus on fecundity. Further, Cr. onyx on the two hosts differ in shell shape, possibly affecting the size of the ctenidium, which Cr. onyx uses for suspension feeding. We examined these potential effects of host use on fitness components in Cr. onyx. Epibionts on mussels reached much larger average sizes than did those on cone snails; further, epibionts on mussels often completed sex change at much larger sizes than did those on cone snails. On average, mussel epibionts had threefold higher average fecundities than did cone snail epibionts. Although there was a slight difference in shell shape between epibionts on the two host species, there was no difference in the scaling of ctenidium area with body size for Cr. onyx from the two hosts. The large average differences in fecundity in epibionts associated with the two alternative hosts suggests that there may be strong selection on host choice at larval settlement. 相似文献
30.
Infestations of corn rootworms (Coleoptera: Chrysomelidae) create economic and environmental concerns in the Corn Belt region of the United States. To supplement the population control tactics of areawide pest management programs, we believe that a better understanding of the spatial relationships between biotic and abiotic or physical factors at the landscape scale is needed. Our research used several geographical information systems (GIS) and spatial analytical techniques to examine relationships between corn rootworm metapopulation dynamics, soil texture, and elevation. Within GIS, several spatially explicit procedures were used that include an interpolation technique, spatial autocorrelation analysis, and contingency analysis. Corn rootworm metapopulation distributions were found to be aggregated and related to soil texture and elevation. We review techniques and discuss our preferences for using particular spatially explicit procedures. The information derived from the spatial analyses demonstrates how GIS can be used in areawide pest management to provide inputs for spatially explicit models to predict future pest populations and formulate more well‐informed pest management decisions. The techniques described in this paper could easily be extended to study the spatial dynamics between other pest populations in agricultural landscapes. 相似文献