UW-Milwaukee Department of Mathematical Sciences presents,
University of Wisconsin-Milwaukee
MS Graduate Student
Friday, April 13, 2018
11:00AM in EMS Building, W434
A Climatology of Extreme South American Andean Cold Surges
This study performs a climatology of extreme South American cold surges which follow along the Andes mountains to document the extent to which these strong surges can modulate the atmosphere deep into the tropics. Data was collected for Austral winter (JJAS) from 1980-2010 (31 years). To identify events, standardized anomalies for 925 hPa meridional wind and temperature are calculated. To ensure the cold surges are on the stronger end of the spectrum, steep conditions of anomalies exceeding three above (below) zero for meridional wind (temperature). Using these criteria, 57 events are identified, and composites and area-averages are created, focused on the same fields used to identify the events. The duration of these events was about four days on average, with the strongest event lasting eight days. On average, when these surges originate in eastern Bolivia they are comprised of temperatures (meridional winds) near three standardized anomalies below (above) normal. It is shown that some extreme cold surge events can have lasting impacts on the lower parts of atmosphere over much of northern South America, with anomalies up to three above (below) zero for meridional wind (temperature) reaching the southern Caribbean.
Profs. Clark Evans (Advisor); Paul Roebber, & Jon Kahl