Scientists at NASA's Goddard Space Flight Center recently used a computer model and satellite data to examine climate over the past century. In the study, cooler than normal tropical Pacific Ocean temperatures and warmer than normal tropical Atlantic Ocean temperatures created ideal drought conditions due to the unstable sea surface temperatures. The result was dry air and high temperatures in the Midwest from about 1931 to 1939.
The Normal Supply of Moist Air From the Gulf of Mexico Was Reduced.
Changes in sea surface temperatures create shifts in weather patterns. One way is by changing the patterns in the jet stream. In the 1930's, the jet stream was weakened causing the normally moisture rich air from the Gulf of Mexico to become drier. Low level winds further reduced the normal supply of moisture from the Gulf of Mexico and reduced rainfall throughout the US Midwest.
Images of the Dust Bowl
The Jet Stream Changed Course.
The jet stream normally flows west over the Gulf of Mexico and turns northward pulling up moisture and dumping rain onto the Great Plains. As the jet stream weakened and changed course, it traveled farther south than normal starving the Midwest of precious rain.
Video Clip of the Jet Strem
For further explanation, watch the brief video clip - How Does the Jet Stream Affect Global Weather Patterns and Influence Droughts? (MPEG 1, 1MB, 10 seconds long. Courtesy of NASA Goddard Space Flight Center Science Visualizations Studio. Video will take you to a new screen and take several seconds to download.) After watching this weather video clip, join the weather forum for a discussion on world climate change issues.
Siegfried Schubert, Max Suarez, Philip Pegion , Randal Koster, and Julio Bacmeister, "On the Cause of the 1930s Dust Bowl", March 19, 2004 SCIENCE Magazine.