Detection and Attribution of Anthropogenic Changes in Climate Extremes and Variability

气候模式被广泛用于预测与温室气体排放增加和其他人为气候影响有关的未来气候变化。对气候变化的探测和归因提供了对气候模式实际模拟与自然和人为影响相关的过去气候变化能力的严格评估。探测方法还提供了一种方法，可根据观测到的变化估计未来变化的概率分布，并可估计温室气体强迫对极端事件风险变化的贡献。科学目标和知识价值：该研究旨在发现和归因于描述极端气候的大规模气候统计变化。这项工作的第一个重点是将指纹检测和归因方法应用于炎热白天和夜晚的变化，以及预测全球范围内强降水的增加，特别是在几天内。结果将用于估计热浪和罕见极端温度风险的人为变化。工作的第二个重点是探索已被确定为对生态系统和社会产生潜在重要影响的极端气候和变异的变化。例如，由于生长期降雨减少或降雨和温度变化共同导致的热浪、假春或干旱。由于最近观测数据集和气候模式模拟在质量和数量上的改进，这项工作现在是可行的。最近，从IPCC第四次评估报告的模拟中获得了大量最新的气候模式模拟。它们可以提供对气候变化信号和这些信号中的模式不确定性的估计。此外，正在收集覆盖全球陆地面积越来越大的日极端温度和极端降雨指数。此外，长站数据也可以用来测试气候模型估算的内部气候变率。更广泛的影响：极端气候对社会、农业和生态系统有很大的影响，气候变化的许多影响可能与极端气候的变化直接相关。因此，了解20世纪遭遇的极端气候变化，并评估气候模式模拟这种变化的能力，对社会具有重要意义。探测极端气候的人为变化对于了解当前气候中出现的风险，以及现实地预测进一步的变化及其不确定性至关重要。该活动对教学和教育也有影响。该预算包括研究生经费，因此用于培训学生了解气候研究的重要问题、与之相关的社会影响以及应用最新统计技术。

Climate models are widely used to predict future climate changes associated with increasing greenhouse gas emissions and other anthropogenic influences on climate. Detection and attribution of climate change provides a rigorous evaluation of the ability of climate models to realistically simulate past climate change associated with natural and anthropogenic influences. Detection methods also provide a means for estimating the probability distribution of future changes based on observed changes, and to estimate the contribution from greenhouse gas forcing to changes in the risk of extreme events. Scientific Objectives and Intellectual Merit: The research aims at detecting and attributing large-scale changes in the statistics of climate that describe extremes. The first thrust of the work is to apply fingerprint detection and attribution approaches to changes in hot days and nights, and projected global-scale increases in heavy precipitation, particularly over several days. Results will be used to estimate anthropogenic changes in the risk of heat waves and rare temperature extremes. A second thrust of work is to explore changes in climate extremes and variability that have been determined as potentially important for impacts on ecosystems and society. Examples are heat waves, false springs, or droughts resulting from decreases in growing season rainfall or combined rainfall and temperature changes. The work is now feasible because of recent improvements in the quality and quantity of observational data sets and climate model simulations. A large set of the latest climate model simulations has recently become available from simulations performed for the 4th IPCC assessment report. These can provide estimates of climate change signals and model uncertainties in these signals. Furthermore, indices of daily temperature and rainfall extremes are being collected that cover an increasing area of the global land mass. Also, long station data are becoming available that allow to test internal climate variability estimates from climate models. Broader Impacts: Climatic extremes have large impacts on society, agriculture, and ecosystems, and many impacts of climate change may be directly related to changes in climate extremes. Therefore, it is of great importance to society to understand the variations in climate extremes encountered over the 20th century, and to evaluate the ability of climate models to simulate such changes. Detection of anthropogenic changes in climatic extremes is essential for understanding emerging risks in the current climate, and realistically predicting further changes and their uncertainties. The activity also has impacts on teaching and education. The budget contains funding for a graduate student, and thus for training a student in important problems of climate research, societal impacts associated with it, and applying up-to-date statistical techniques.