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

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 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, continued from a previous study, where we contrast the vertical thermodynamic structure of the atmosphere over two sites in the Midwest (Lincoln, Illinois, and Springfield, MO, in the heart of the drought-stricken region) for every day of June, July and August 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 the summers of 2012 and 1988, to give a unique view of seasons 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.