Submitted to Journal of Geophysical Research-Atmospheres 28

• Main Authors: Song Feng, Robert J. Oglesby, Clinton M. Rowe, David B. Loope, Qi Hu
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Pacific; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.561.5648; http://snr.unl.edu/climate_change/research/mwp.pdf

Abstract 1 Severe drought is arguably the greatest recurring natural disaster that strikes 2 North America. A synthesis of multi-proxy data shows that North America was in the 3 grip of a severe centennial-scale drought during medieval times (800-1300 AD). In this 4 study, the Community Atmospheric Model (CAM) is used to investigate the role of sea 5 surface temperatures (SSTs) anomalies from the tropical Pacific and the North Atlantic 6 Ocean on this mega-drought. These anomalies are obtained from proxy reconstructions of 7 SST. Four model experiments with prescribed SST anomalies in the tropical Pacific 8 and/or North Atlantic Ocean were made. The CAM results captured the major dry 9 features that occurred during medieval times in North America. The cold tropical Pacific 10 alone can simulate essentially the entire drought area extent, while the warm North 11 Atlantic alone can simulate the drought in the High Plains and the western U.S. The two 12 working together can explain the severity and longevity of the drought. During the spring 13 and summer rainy season, the cool tropical Pacific, or the warm North Atlantic, or both, 14 results in less moisture transport to the High Plains, with a 15-40 % decrease in rainfall. 15