P2C2: Megadrought--Local versus Remote Causal Factors for Medieval North America

研究人员将调查（1）海洋表面温度（SST）的远程强迫和（2）当地陆地表面-大气相互作用的相对作用和对北美中世纪干旱的反馈，大约公元900-1300年在这段时间里，发生了一系列数十年的干旱，总的来说，持续的时间比仪器使用期间发生的任何“严重”干旱都长（例如20世纪30年代的沙尘暴）。具体来说，NCAR社区大气模式（CAM4.0）将用于研究热带太平洋海温异常的影响和机制，以及更确定和持续的流域-北大西洋温暖的海温异常对中世纪干旱的影响。 此外，天气研究和预报（WRF）模型，迫使从CAM4.0的输出，将被用来评估植被破坏和土壤水分在延长，加强，或修改干旱的作用。 特别是，WRF将被用来研究在中世纪时期美国中部发生的前所未有的风转移中植被破坏的作用。本科生和研究生将参与该项目。此外，研究小组将与国家干旱缓解中心（NDMC）和内布拉斯加大学林肯分校（UNL）的其他外展小组合作，提高对特大干旱造成的潜在水危机的认识。该项目有关干旱的信息还将通过国家干旱监测中心的季度通讯和Nebguide（联合国图书馆推广出版物之一）传播，并免费向公众分发。

The researchers will investigate the relative roles of (1) remote forcing of sea surface temperatures (SST) and (2) local land surface-atmosphere interactions and feedbacks on the medieval drought in North America, approximately 900-1300 A.D. During this time, a series of multi-decadal droughts occurred which, in total, lasted longer than any 'severe' drought that has occurred during the instrumental period (e.g. the 1930's Dust Bowl).Specifically, the NCAR community atmospheric model (CAM4.0) will be used to investigate the impacts and mechanisms of SST anomalies in the tropical Pacific as well as the more certain and persistent basin-wide warm SST anomalies in the North Atlantic on medieval drought. Additionally, the Weather Research and Forecast (WRF) model, forced by output from CAM4.0, will be used to evaluate the role of devegetation and soil moisture in prolonging, enhancing, or modifying the drought. In particular, WRF will be used to examine the role of devegetation in the unprecedented wind shift which took place in the central U.S. during the Medieval Period.Undergraduate and graduate students will participate in the project. In addition, the research team will collaborate with the National Drought Mitigation Center (NDMC) and other outreach groups at the University of Nebraska-Lincoln (UNL) to increase awareness of potential water crises due to megadroughts. Drought-related information from the project would also be disseminated through the NDMC's quarterly newsletter and Nebguide (one of the UNL extension publications) and distributed free to the public.