美军军事极端环境选择的科学表征

介绍了美国陆军研究办公室资助陆军研究实验室环境科学部和陆军军官学校地理与环境工程部,研发了通过地理环境分析提高利用自然环境进行试验和训练的科学判据,实现了表征任意环境试验站点支持试验任务的能力.在地理环境位置分析中,采用了8步骤环境试验站评价分析模型,并给出了理想热带试验区环境条件分析和理想沙漠环境精确的地理学参数分析案例.为最优化试验站点选择,还研发了附加关键自然环境因素评价等级.研究成果的创新在于通过科学的标准将选择全球最佳自然环境进行现场试验和军事行动的需求与地理背景环境联系起来,能够对相关环境试验站的选择进行科学表征和评估,实现装备/材料现场试验与部队训练效益最大化.     

极端降雨下绿基和灰基联用的雨洪控制效果

以福州大学为例,选取3种绿色基础措施（绿色屋顶、植被浅沟、渗透铺装）与2种灰色基础设施（增大管径、蓄水池）组合,设计了9种雨水系统改造措施方案,并根据3场不同历时极端天气降雨的实测数据,运用暴雨洪水管理模型（SWMM）模拟分析不同雨水系统改造措施方案对径流深、节点和管道的雨洪控制效果.情景模拟结果表明：3场强降雨下,绿色基础措施组合（SS7）在所有用地布局情景中对径流深的控制效果均为最优,其中中长历时强降雨下的削减比最高,达到了78%;在节点控制方面,由于3种绿色基础措施与增大管径组合措施（SS8）具备下渗、滞留和快排等特性,在3场降雨中,对节点的洪流流量和洪流时间的控制效果均为最优,接近100%;在管道控制方面,3种含绿色基础措施的组合方案（SS7,8,9）对管道满流时间与峰值流量发生时间的控制较好.通过对比这3种组合措施方案发现,在短历时强降雨中,3种绿色基础措施与蓄水池组合措施方案下（SS9）管道满流时间最短,峰值流量发生时间最迟;中长历时强降雨中3者差别不大;长历时强降雨中3种绿色基础措施组合下（SS7）管道满流时间最短,峰值流量发生时间最迟.     

Refuge‐Effect Hypothesis and the Demise of the Dodo

The Dodo was last sighted on the inshore island of Ile d'Ambre in 1662, nearly 25 years after the previous sighting on the mainland of Mauritius. It has been suggested that its survival on the inshore island is representative of the refuge effect. Understanding what constitutes significant persistence is fundamental to conservation. I tested the refuge‐effect hypothesis for the persistence of the Dodo (Raphus cucullatus) on an inshore island beyond that of the mainland population. For a location to be considered a refuge, most current definitions suggest that both spatial and temporal isolation from the cause of disturbance are required. These results suggest the island was not a refuge for the Dodo because the sighting in 1662 was not temporally isolated from that of the mainland sightings. Furthermore, with only approximately 350 m separating Ile d'Ambre from the mainland of Mauritius, it is unlikely this population of Dodos was spatially isolated. Hipótesis del Efecto Refugio y la Desaparición del Dodo     

基于均一化降水资料的中国极端降水特征分析

论文利用中国1961—2012年602个测站均一化的日降水资料,基于世界气象组织定义的11个极端降水指数,分析了近52 a中国极端降水事件的时空分布特征。结果表明：年极端降水指数长期变化趋势表明,大部分极端降水指数在我国西北和长江中下游地区（除CDD）以及东南沿海和华南大部分地区均呈现增加趋势,而在华北地区为减少趋势。极端降水指数随时间的变化表明,各指数具有明显的年际和年代际变化,从2000年开始大部分指数表现为不同程度的增加趋势,即极端降水事件从2000年开始偏多。     

基于门限极值理论的湖泊水质参照状态的确定

在前人工作的基础上,利用门限极值的广义Pareto分布理论和超出阈值峰(Peak Over Threshold,POT)方法,提出了一种确定湖泊参照状态浓度的新方法.该方法不仅能够给出更为精确的置信区间,而且克服了广义极值分布理论取用数据浪费等缺陷.将该方法应用到太湖的水质基准参照状态中,通过POT方法对太湖8个站点1995~2006年总氮(TN),总磷(TP)和叶绿素a(Chl-a)的数据进行预处理,分别以-1.0mg/L, -0.05mg/L与-4μg/L作为它们观测值相反数的门限值,结果表明观测值的相反数符合广义Pareto分布,验证了方法的可行性.推荐采用25%分位点的值作为太湖总氮,总磷和叶绿素a的参照状态,即太湖的参照状态是:总氮0.66mg/L;总磷0.023mg/L;叶绿素a为1.27μg/L.最后分别得出了它们各自的95%置信区间,而且其精度明显高于广义极值分布理论结果.     

REGIONAL FREQUENCY ANALYSIS OF HYDROLOGIC MULTIYEAR DROUGHTS1

This paper is concerned with regional frequency analysis of hydrologic multiyear droughts. A drought event is defined by three parameters: severity, duration, and magnitude. A method is proposed here to standardize drought severities with a duration adjustment to enable comparison among drought events. For purposes of a regional study, the index drought method is selected and applied to standardized droughts to give a regional frequency curve. However, the recurrence intervals of the drought events obtained from index drought method are limited to the historic period of record. Therefore, by taking advantage of random variations of droughts in both time and space, a multivariate simulation model is used to estimate exceedence probabilities associated with regional drought maxima. This method, named the regional extreme drought method, is capable of generating a series of drought events which, although they have not occurred historically, are more severe than historic events. By combining the results of the index drought method and regional extreme drought analysis, a regional drought probability graph is constructed which ranges from severe droughts to more frequent droughts. This procedure is applied to the mean annual flow records of streams located in the San Joaquin Valley of California, and drought-severity-frequency plots are prepared for 1-year, 2-year, and 3-year durations.     

1961-2009年四川极端强降水变化趋势与周期性分析

利用四川1961-2009年141个站点逐日降水资料和1998-2007年灾情资料,采用气候倾向率、Mann-Kendall检验、复Morlet小波、Gumbel分布、信息扩散等方法,分析了7个区域5个指数的变化趋势、突变特征和周期性特点,以及重现期降水极值和洪灾损失风险的区域差异,其主要结论是:川西南山地极端降水呈显著增多增强趋势,并在1980年代初发生了突变,盆地东北部和川西高原南部也有增多增强趋势,但不显著,盆地西北部、盆地南部和川西高原北部则有减少减弱趋势,盆地中部则表现出频数增多强度减弱的变化趋势;多数区域和多数指数都存在25 a左右的长周期和6~9 a的短周期,从25 a的长周期看,目前极端降水正处于增多增强的变化过程之中;用Gumbel分布拟合的日最大降水量,其极值区位于盆周山区和高原与盆地的过渡带,3个极值中心主要位于盆地西南部、西北部和东北部,50 a一遇的日雨量在230 mm以上;盆地大部50 a一遇的洪灾损失率在38%左右,盆地东北部可达45%,广元西南部可达60%。     

Migration as an adaptive strategy to climate variability: a study of the Tonga‐speaking people of Southern Zambia

There is increasing consensus that the effects of extreme weather conditions in the form of drought, flooding and extreme temperature will have increasingly devastating impacts on those who depend on climate‐sensitive resources and ecosystems for their livelihoods. The most affected will be the poor in developing countries who have a low adaptive capacity to climate change due to high poverty levels. Despite these projections, there are, to date, insufficient empirical studies linking the relationship between climate change and migration, particularly in the context of southern Africa. Using field‐based data collected from two study locations in Zambia, this paper examines the complex relationship between extreme weather events and population movement. It is envisaged that the findings presented in this paper will contribute to current discussions on the complex relationship between extreme weather conditions and population movement specifically in the context of sub‐Saharan Africa and other developing countries.     

Forecast-based action for conservation

Extreme weather events pose an immediate threat to biodiversity, but existing conservation strategies have limitations. Advances in meteorological forecasting and innovation in the humanitarian sector provide a possible solution—forecast-based action (FbA). The growth of ecological forecasting demonstrates the huge potential to anticipate conservation outcomes, but a lack of operational examples suggests a new approach is needed to translate forecasts into action. FbA provides such a framework, formalizing the use of meteorological forecasts to anticipate and mitigate the impacts of extreme weather. Based on experience from the humanitarian sector, I suggest how FbA could work in conservation, demonstrating key concepts using the theoretical example of heatwave impacts on sea turtle embryo mortality, and address likely challenges in realizing FbA for conservation, including establishing a financing mechanism, allocating funds to actions, and decision-making under uncertainty. FbA will demand changes in conservation research, practice, and governance. Researchers must increase efforts to understand the impacts of extreme weather at more immediate and actionable timescales and should coproduce forecasts of such impacts with practitioners. International conservation funders should establish systems to fund anticipatory actions based on uncertain forecasts.     

Variability and predictability of sea-level extremes in the Hawaiian and U.S.-Trust Islands—a knowledge base for coastal hazards management

The objective of this study is to provide an improved climatology of sea level extremes on seasonal and long-term time scales for Hawaii and the U.S-Trust islands. Observations revealed that the Hawaiian and U.S.-Trust islands, by and large, display a strong annual cycle. For estimating the statistics of return period, the three-parameter generalized extreme value (GEV) distribution is fitted using the method of L-moments. In the context of extremes (20- to 100-year return periods), the deviations in most of the Hawaiian Islands (except at Nawiliwili and Hilo) displayed a moderate sea-level rise (i.e., close to 200 mm), but the deviations in the U.S.-Trust islands displayed a considerably higher rise (i.e., more than 300 mm) in some seasons due to typhoon-related storm surges. This rise may cause damage to roads, harbors, and unstable sandy beaches. Correlations between the El Niño-Southern Oscillation (ENSO) climate cycle and the variability of seasonal sea level have been investigated. Results show that correlation for the station located west of the International Date Line (DL) is strong, but it is moderate or even weaker for stations east of the DL. The skill of SST-based Canonical Correlation Analyses (CCA) forecasts was found to be weak to moderate (0.4–0.6 for Honolulu, Kahului, Hilo, and Wake, and 0.3 or below for Kahului, Mokuoloe, and Johnston). Finally, these findings are synthesized for evaluating the potential implications of sea level variability in these islands.