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Pluvial lakes were abundant in the southwestern United States during Pleistocene glaciations, particularly in the Great Basin. Many of these lakes occupied closed basins; therefore, fluctuations of their water surface elevations are valuable sources of paleoclimate information. Histories of the largest lakes are well constrained, whereas dozens of smaller lakes that were present in this region have received relatively little scientific attention. Given their dimensions, these smaller lakes were climatically sensitive and can offer important information about Quaternary climate variability. Here we present new ages for the highstands of three previously undated small lakes based on radiocarbon dating of gastropod shells recovered from beach ridges. These results are combined with other published and unpublished 14C ages to yield an extensive compilation of highstand shoreline ages for lakes of all sizes throughout the southwestern US. The results indicate that although some lakes reached highstands during the Last Glacial Maximum, the strongest temporal correspondence is between highstands and Heinrich Event H1. These results are consistent with speleothem‐based reconstructions of effective moisture in the southwestern US, which show increased precipitation during stadials of the last glacial cycle. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Benjamin L. Preston 《Global Environmental Change》2013,23(4):719-732
Despite improvements in disaster risk management in the United States, a trend toward increasing economic losses from extreme weather events has been observed. This trend has been attributed to growth in socioeconomic exposure to extremes, a process characterized by strong path dependence. To understand the influence of path dependence on past and future losses, an index of potential socioeconomic exposure was developed at the U.S. county level based upon population size and inflation-adjusted wealth proxies. Since 1960, exposure has increased preferentially in the U.S. Southeast (particularly coastal and urban counties) and Southwest relative to the Great Plains and Northeast. Projected changes in exposure from 2009 to 2054 based upon scenarios of future demographic and economic change suggest a long-term commitment to increasing, but spatially heterogeneous, exposure to extremes, independent of climate change. The implications of this path dependence are examined in the context of several natural hazards. Using methods previously reported in the literature, annualized county-level losses from 1960 to 2008 for five climate-related natural hazards were normalized to 2009 values and then scaled based upon projected changes in exposure and two different estimates of the exposure elasticity of losses. Results indicate that losses from extreme events will grow by a factor of 1.3–1.7 and 1.8–3.9 by 2025 and 2050, respectively, with the exposure elasticity representing a major source of uncertainty. The implications of increasing physical vulnerability to extreme weather events for investments in disaster risk management are ultimately contingent upon the normative values of societal actors. 相似文献
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Elizabeth Mcleod Benjamin Poulter Jochen Hinkel Enrique Reyes Rodney Salm 《Ocean & Coastal Management》2010,53(9):507-517
Conservation managers and policy makers need tools to identify coastal habitats and human communities that are vulnerable to sea-level rise. Coastal impact models can help determine the vulnerability of areas and populations to changes in sea level. Model outputs may be used to guide decisions about the location and design of future protected areas and development, and to prioritize adaptation of existing protected area investments. This paper reviews state-of-the-art coastal impact models that determine sea-level rise vulnerability and provides guidance to help managers and policy makers determine the appropriateness of various models at local, regional, and global scales. There are a variety of models, each with strengths and weaknesses, that are suited for different management objectives. We find important trade-offs exist regarding the cost and capacity needed to run and interpret the models, the range of impacts they cover, and regarding the spatial scale that each operates which may overstate impacts at one end and underestimate impacts at the other. Understanding these differences is critical for managers and policy makers to make informed decisions about which model to use and how to interpret and apply the results. 相似文献
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Olynk Widmar Nicole Rash Kendra Bir Courtney Bir Benjamin Jung Jinho 《Natural Hazards》2022,110(2):961-998
Natural Hazards - Increasing prevalence and scale of natural disasters fuel the need for new approaches to evaluating, and eventually mitigating, their impact. This analysis quantifies and compares... 相似文献
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WorldMap is an open source online mapping application which aims to lower barriers for scholars who wish to visualize, analyze, organize, present, and publish mapped information. In late 2013, 290 respondents among the 8,000 registered users participated in an online survey in which they described their activities, purposes, experiences, and preferences regarding the system. Participants also described their professional background, GIS skill level, age, gender, and country of work. This study analyzes the results of the survey, by summarizing the responses to each question independently and by examining the relationships and dependencies of these answers across the different questions to try to better understand why users responded the way they did. The study is based on the user‐centered design (UCD) approach. We aim to use the survey results to improve our understanding of user demographics and needs. Findings from this study will be used to guide WorldMap improvements, and we hope the findings will also shed light on the broader requirements of online GIS users. 相似文献
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Meghan E. Gray Christian Wolf Marco Barden Chien Y. Peng Boris Häußler Eric F. Bell Daniel H. McIntosh Yicheng Guo John A. R. Caldwell David Bacon Michael Balogh Fabio D. Barazza Asmus Böhm Catherine Heymans Knud Jahnke Shardha Jogee Eelco van Kampen Kyle Lane Klaus Meisenheimer Sebastian F. Sánchez y Taylor Lutz Wisotzki Xianzhong Zheng David A. Green R. J. Beswick D. J. Saikia Rachel Gilmour Benjamin D. Johnson Casey Papovich 《Monthly notices of the Royal Astronomical Society》2009,393(4):1275-1301
We present an overview of the Space Telescope A901/2 Galaxy Evolution Survey (STAGES). STAGES is a multiwavelength project designed to probe physical drivers of galaxy evolution across a wide range of environments and luminosity. A complex multicluster system at z ∼ 0.165 has been the subject of an 80-orbit F606W Hubble Space Telescope (HST) /Advanced Camera for Surveys (ACS) mosaic covering the full span of the supercluster. Extensive multiwavelength observations with XMM–Newton , GALEX, Spitzer , 2dF, Giant Metrewave Radio Telescope and the 17-band COMBO-17 photometric redshift survey complement the HST imaging. Our survey goals include simultaneously linking galaxy morphology with other observables such as age, star formation rate, nuclear activity and stellar mass. In addition, with the multiwavelength data set and new high-resolution mass maps from gravitational lensing, we are able to disentangle the large-scale structure of the system. By examining all aspects of an environment we will be able to evaluate the relative importance of the dark matter haloes, the local galaxy density and the hot X-ray gas in driving galaxy transformation. This paper describes the HST imaging, data reduction and creation of a master catalogue. We perform the Sérsic fitting on the HST images and conduct associated simulations to quantify completeness. In addition, we present the COMBO-17 photometric redshift catalogue and estimates of stellar masses and star formation rates for this field. We define galaxy and cluster sample selection criteria, which will be the basis for forthcoming science analyses, and present a compilation of notable objects in the field. Finally, we describe the further multiwavelength observations and announce public access to the data and catalogues. 相似文献