Simulating Multi-Season Past Droughts
Abstract

Abstract Author: Y. Fan, W. Wu and H. vandenDool

Abstract Title: North American Drought in the Past 8 Decades

Abstract: Drought is one of the natural disasters that can happen anytime and anywhere. Different droughts can have different severity, duration and spatial coverage. Those severe droughts that cover a large-scale space and last long term period can bring major disasters to the human society and earth’s ecosystems. Hence, do our current land surface modeling and monitoring systems have the capability to reproduce the droughts that have occurred in the past multi-decades and what are the main causes for the major droughts in North America? To better understand the attributions of the major droughts and to predict them are not only very important for science, but also have great benefits to protect human society.

Soil moisture responds to precipitation accumulation like a low-pass filter and is a very significant physical variable for drought monitoring and studies. A long-term (1931 to present) land surface soil moisture dataset from the CPC leaky bucket land surface hydrological model, which was forced with observed precipitation and 2m surface air temperature, was used to study droughts and their variations in North America for the past eight decades. The preliminary results show that the major droughts occurring in the past 8 decades were very well captured in terms of severity, duration and spatial distribution. Further detailed studies were conducted in order to address scientific issues like: How did the droughts respond to the observed precipitation and temperature changes? Did any drifting of the frequencies, magnitudes and locations of the droughts happen over the past 8 decades? We also used the global SST data set and soil moisture data set etc to explore if any possible main reasons for the origins of those major droughts in North America.