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

近年来，由于全球变暖，全球范围内的强风暴发生得越来越频繁，强度也越来越大，这可能导致工程设计中现有的强度-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，根据城市现有的IDF曲线，暴风雨应该每100年发生一次。2013年6月，阿尔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加拿大大部分以积雪为主的流域的水资源供应，因为气候变暖意味着春季融雪提前，夏季蒸发损失增加，导致夏季生长季节最需要的夏季流量减少。这项研究将促进我们对气候变化的理解，以及我们预测气候变暖对加拿大气候和水资源变化的影响的能力。(1)考虑到不同气候条件对气候变化影响的响应不同，对加拿大特定地区的极端降水事件进行深入分析，评估其空间变异性和预估变化；(2)检验常用的极端降水指数在这些地区的适用性，开发新的极端降水指数；(3)根据IPCC（2013）最新的RCP （Representative Concentration Pathway）气候情景，基于区域气候模式与陆地表面模式耦合模拟估算的区域IDF曲线，估算未来极端风暴的重现期；(4)利用观测到的气候数据和通用干旱指数算法对加拿大连贯地区的夏季进行干旱分析；(5)为了解气候变化对未来干旱的影响，将在2050年代和2080年代对RCP气候情景进行统计或动态缩减模拟。为了模拟历史上与加拿大西部低于正常降水相关的气候变化和厄尔尼诺事件可能产生的综合影响，将采用bootstrap重新采样方法生成30年期间的数据集，这些数据集基于2050年代和2080年代的RCP气候情景和ENSO，使用分位数-分位数制图方法对气候变化的综合影响进行了调整。气候变化对以春季融雪为主的加拿大流域未来水源的潜在影响将通过IPCC（2013）缩小比例的RCP气候情景强迫的水文模式进行模拟。最后，将审查适应战略、预警系统和能力建设措施，以促进加拿大应对气候变化影响的准备工作。

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 Nio 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.