Impacts of climatic and environmental changes to Hydrologic Extremes and Adaptation strategies

近年来，由于全球变暖，严重风暴在世界各地发生的频率更高，强度更大，这可能导致现有的工程设计强度-持续时间-频率(IDF)曲线过时，例如，埃德蒙顿的数千个地下室在1995年、2004年和2012年被洪水淹没，根据现有的IDF曲线，埃德蒙顿本应每100年发生一次。2013年6月，艾伯塔省南部的洪水造成了60亿美元的损失。另一方面，2001/02年的干旱造成了数十亿美元的农业收入损失。气候变暖的另一个影响将是以积雪为主的大多数加拿大流域的水资源可获得性，因为气候变暖意味着春季积雪提前融化，夏季蒸发损失增加，导致夏季生长季最需要的夏季径流减少。这项研究将促进我们对气候变化的理解，以及我们预测变暖对加拿大气候和水资源变化的影响的能力。具体来说，对于洪水灾害：(1)深入分析极端降水事件，以评估其在加拿大选定区域的空间变异性和预测变化，因为不同的气候制度对气候变化影响的反应不同；(2)测试常用的极端降水指数在这些地区的适用性，并制定新的极端降水指数；(3)根据区域气候模式和陆面模式的模拟估计的区域IDF曲线，估计未来极端风暴的重现期，以考虑陆地-大气反馈，并受IPCC(2013)最新的RCP(代表集中路径)气候情景的制约；(4)利用观测的气候数据和通用的干旱指数算法对加拿大相关地区的夏季进行干旱分析；(5)为了了解气候变化对未来干旱的影响，将从统计或动态缩小的2020年代和2020年代的RCP气候情景中模拟选定的干旱指数。为了模拟气候变化和厄尔尼诺事件可能产生的综合影响，历史上与加拿大西部降水低于正常水平有关的厄尔尼诺事件，将使用自举重采样方法，根据RCP气候情景和ENSO的综合影响，使用分位数-分位数映射方法，生成针对2050年代和2020年代气候变化的综合影响进行调整的30年周期数据集。气候变化对以春季融雪为主的加拿大分水岭未来水源的潜在影响将由一个水文模型模拟，该模型强制采用IPCC(2013)缩小尺度的RCP气候情景。最后，将审查适应战略、预警系统和能力建设措施，以促进加拿大为应对气候变化影响做好准备。

In recent years, severe storms have been occurring more frequently and in greater intensity across the world because of global warming, which could cause existing Intensity-Duration-Frequency (IDF) curves for engineering design obsolete, e.g., thousands of basements of Edmonton were flooded in 1995, 2004 and 2012, by storms which based on existing IDF curves for the City are supposed to occur once every 100 years. In June 2013, the southern Alberta flood incurred a damage of $6 billion. On the other hand, the drought of 2001/02 had caused loss of multibillion dollar revenues from agriculture. Another impact of warming will be the water availability of most Canadian watersheds dominated by snowpack because a warmer climate means an earlier onset of spring snowmelt and enhanced evaporation loss in the summer, resulting in decreased summer streamflow most needed for summer growing seasons. This research will advance our understanding of climate change and our ability to predict the impact of warming to changes in the climate and water resources of Canada. Specifically, for flood hazards: (1) To conduct in-depth analysis of extreme precipitation events to assess their spatial variability and projected changes in selected regions across Canada, given that different climatic regimes can respond differently to climate change impact; (2) To test the applicability of commonly used extreme precipitation indices over these regions, and to develop new extreme precipitation indices; (3) To estimate return periods of future extreme storms based on regional IDF curves estimated from simulations of a regional climate model coupled to a land surface model to account for the land-atmosphere feedback and subjected to the latest RCP (Representative Concentration Pathway) climate scenarios of IPCC (2013); (4) To conduct a drought analysis using observed climate data and versatile drought index algorithms for summer over coherent regions of Canada; (5) To understand the impact of climate change to future droughts, selected drought indices will be simulated from RCP climate scenarios statistically or dynamically downscaled for 2050s and 2080s. To simulate the possible combined impact of climate change and El Niño events historically associated with below normal precipitation in western Canada, a bootstrap resampling approach will be used to generate 30-year period datasets adjusted for the combined impact of climate change based on RCP climate scenarios and ENSO using the quantile-quantile mapping method for 2050s and 2080s. The potential impact of climate change to the future water sources of Canadian watersheds dominated by spring snowmelt will be simulated by a hydrologic model forced with downscaled RCP climate scenarios of IPCC (2013). Lastly, adaptation strategies, early warning systems and capacity building measures will be examined to promote preparedness of Canada against climate change impact.