An Analysis of Tropical Moisture Transport During Agricultural Drought Transition Periods Over the United States Corn Belt Region

Drought has tremendous socioeconomic and environmental impacts, across the full spectrum of drought time scales from weeks to decades. The United States is the world's largest producer of maize and is especially susceptible to agricultural drought as much of the production is unirrigated. Much of the literature on the development and breakdown of agricultural drought (defined as anomalously dry conditions for 1 – 3 weeks) has attributed these transition states to chaotic synoptic weather events. While many strides have been made in the monitoring and understanding of drought over the past several decades, the broader atmospheric and hydrometeorological communities lack a strong dynamic understanding of how drought evolves on synoptic, subseasonal, and intraseasonal time scales, and in particular, what mechanisms explain transitions toward or away from drought.

This study assesses the role of moisture transport in triggering agricultural drought transition periods. Stark contrasts in zonal, meridional and vertical transport of vertically integrated specific humidity between transitions toward and away from drought gleam insight into the many different scale interactions associated with drought transition periods. This presentation will focus on moisture transport on seasonal, intraseasonal, and synoptic timescales to asses the relative contribution each has during transition periods.