ABSTRACT
Recent severe droughts in the southeastern and central United States (Bergman et al. 1986; Trenberth et al. 1988) have emphasized, once again, that a tenuous reliance of the United States on precipitation exists even for non-arid regions, because sufficient water is always required to support the needs of crops, forests, industries, and municipalities. Although technology and conservation can ameliorate some of the impact of drought on society, the need still exists to better understand the climate dynamics that determine the frequency, intensity, and duration of drought in a given region. This need is being driven, in part, by the desire for better long-range climate predictions that would be useful for planning purposes. In addition, there is the urgent need to develop a better theoretical understanding of how the climate system operates on time scales of years to centuries because of the anticipated impact of “greenhouse” warming on global and regional climates (NOAA 1989).
