P2C2: North American Megadrought: Atmosphere-Ocean Forcing and Landscape Response from the Medieval Period to the Near-Term Greenhouse Future

提供资金用于调查景观和植被反馈是否在造成中世纪特大干旱的严重性和持久性方面发挥了作用，以及这些反馈是否也可能影响未来人为引起的干旱。具体地说，研究人员将：1)创建新的基于海洋代理的中世纪热带海洋表面温度(SST)重建，并使用这些重建来强制大气模型，试图模拟巨灾。由此产生的气候学模型将被用来迫使植被模型估计特大干旱期间的植被变化。这些估计数将用于开发额外的大气模型模拟(使用交互式沙尘模块)，将SSTs的影响、植被的清除、扩大的尘埃源和气溶胶负荷结合在一起。其他大气模型模拟将被迫使用根据古环境数据估计的改变的植被和尘源边界条件；2)强迫植被模型预测未来气候(来自政府间气候变化专门委员会评估报告4)，以确定将用作未来气候变化额外模拟的边界条件的植被和尘源的变化；以及3)努力开发一个完全耦合的地表-植被-尘埃模块，将其纳入戈达德空间研究所(GISS)模型，用于对SST强迫的中世纪大干旱和未来气候的额外模拟。更广泛的影响包括支持本科生和研究生，支持一名新的研究人员，并促进对与气候有关的干旱的理解。该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)提供资金的。

Funding is provided to investigate whether landscape and vegetation feedbacks played a role in creating the severity and persistence of Medieval megadroughts and if these feedbacks might also impact future anthropogenic-induced aridification. Specifically, the researchers will: 1) create new marine proxy-based reconstructions of tropical sea surface temperatures (SSTs) for the Medieval period and use these to force atmosphere models in an attempt to simulate the megadroughts. The resulting modeled climatology will then be used to force vegetation models to estimate vegetation change during the megadroughts. These estimates will be used to develop additional atmosphere model simulations (with an interactive dust module) that combine the impact of SSTs, removal of vegetation and expanded dust sources and aerosol loading. Other atmosphere model simulations will be forced with altered vegetation and dust source boundary conditions as estimated from paleoenvironmental data; 2) force vegetation models with projections of future climate (from the Intergovernmental Panel on Climate Change Assessment Report 4) to determine changes in vegetation and dust sources that will be used as boundary conditions in additional simulations of future climate change; and 3) work to develop a fully coupled land surface-vegetation-dust module for inclusion in the Goddard Institute for Space Studies (GISS) model for use in additional simulations of SST-forced Medieval megadroughts and of future climate.The broader impacts involve supporting undergraduate and graduate students, supporting a new researcher, and contributing to the understanding of climate-related drought. This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).