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

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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.