Variability in Atmospheric Thermodynamic Soundings (VATS): The Drought of Summer 2012

The summer of 2012 was a difficult one for Midwesterners. By the end of July, much of Indiana, Illinois, Missouri and Arkansas were experiencing drought conditions ranging from “severe” to “extreme”. As of August 7th, over 52% of the U.S. was in a “moderate”, “severe”, “extreme” or “exceptional” drought. The impact upon the Corn Belt has been predicted to be similar to the last serious drought in 1988. The USDA announced in mid-July that over 1000 counties in 29 states were eligible for drought disaster assistance.

This study consists of an analysis of the Summer 2012 drought, where we contrast the vertical thermodynamic structure of the atmosphere over one site in the Midwest (Lincoln, Illinois, in the heart of the drought-stricken region) with those of the past. Specifically, we evaluate factors such as instability, moisture and buoyancy in rawinsonde data taken by the National Weather Service over the Midwest for every day in June, July and August over the past 20 years, i.e., build a climatology of these characteristics, and compare them with those derived from data from Summer 2012, to give a unique view of a season of drought within the upper atmosphere. We also start to explore both the impact of the drought upon the vertical structure of the atmosphere, and how too it may have fed back into prolonging drought conditions.

This study was conducted as part of an ongoing junior-level, research-oriented laboratory at Purdue University in the Atmospheric Science program.