Collaborative Research: EaSM2--Quantifying and Conveying the Risk of Prolonged Drought in Coming Decades

干旱是最具破坏性的自然灾害之一，预计在全球变暖的情况下将变得越来越普遍。未来，自然水文气候变率将叠加在持续的人类驱动的区域气候变化上，长期变暖和区域干旱都可能加剧未来的干旱。年代际预测和气候变化预测面临的最大挑战之一是对脆弱地区长期干旱风险的量化，以及将有关这一风险的知识纳入许多资源管理者和处理干旱问题的其他利益攸关方的决策过程。这个项目的重点是干旱变化的尺度——从年代际到多年代际——它既没有很好地受到观测的约束，也没有很好地在模型中得到体现。该活动依赖于综合利用卫星、仪器和古气候观测，以及气候模式和分析，以了解自然和人类对干旱的影响、潜在的模式偏差，以及土地覆盖变化（植被和沙尘）、海洋温度和干旱背后的其他因素的作用。目标是改进对干旱风险的估计，以及改进科学家和利益相关者之间的伙伴关系，这是减少社会对干旱的脆弱性所必需的。将确定关键的脆弱地区，在这些地区，自然变率和人为变化结合起来会加大长期严重干旱的风险，造成严重后果：北美西南部（美国和墨西哥）、澳大利亚、亚马逊地区和西非/萨赫勒地区。该战略利用了几种独特的观测、模式和利益相关者资源：(1)利用最先进的地球系统模式（CESM）对过去一千年进行了前所未有的大量模拟；(2)越来越多的已发表的和新出现的古气候数据集，这些数据集来自多个代用物，揭示了年代用-多年代用水文气候变率的长期观测历史；(3)美国西南部、墨西哥及其他地区的利益相关者和合作者的长期网络，我们可以与他们一起开发将干旱风险评估应用于广泛社会背景下的现实问题的最佳实践；(4)研究干旱变异性和利益相关者驱动的悠久历史。

Drought is among the most ruinous of natural disasters and is expected to become increasingly prevalent in a warming world. In the future, natural hydroclimatic variability will be superimposed on continued human-driven changes to regional climate, with both long-term warming and regional drying likely to exacerbate droughts of the future. Among the greatest challenges of decadal prediction and climate change projection are the quantification of prolonged drought risk in vulnerable regions and the integration of knowledge about this risk into the decision-making processes of the many resource managers and other stakeholders who deal with drought. This project focuses on a scale of drought variability - decadal to multidecadal - that is not well constrained by observations, nor well represented in models. The activity relies on the integrated use of satellite, instrumental, and paleoclimatic observations, along with climate models and analysis, to understand both the natural and human influences on drought, potential model biases, and the roles of land cover change (vegetation and dust), ocean temperatures, and other factors behind drought. The goal is to develop improved estimates of drought risk, as well as the improved partnerships between scientists and stakeholders that are required to reduce the vulnerability of society to drought. Key vulnerable regions will be identified, where natural variability and anthropogenic change combine to amplify the risk of prolonged, severe drought with large consequences: southwestern North America (US and Mexico), Australia, the Amazon, and West Africa/Sahel. The strategy takes advantage of several unique observational, model and stakeholder resources: (1) an unprecedented number of simulations of the past millennium from a state-of-the-art Earth System Model (CESM; in addition to the CMIP5 archive); (2) an expanding set of published and emerging paleoclimate datasets from multiple proxies that reveal long observational histories of decadal-multidecadal hydroclimate variability; (3) a longstanding network of stakeholders and collaborators in the southwestern US, Mexico, and beyond with whom we can develop best practices in applying drought risk estimates to real-world problems across a broad social context; and (4) a long history of working on drought variability and stakeholder-driven.