Collaborative Research: Variations and Trends in Fall Precipitation over the Central United States: Issues of Physical Mechanisms, Circulation Anomalies and Boundary Forcing
DESCRIPTION: The project will focus on three themes to better understand precipitation patterns in the United States during fall: 1) mechanisms that produce trends and decadal variations in fall precipitation and how they are represented in models; 2) how are these mechanisms dominant in fall and not other seasons; and 3) how to identify physical linkages between decadal variations in fall and Pacific or Atlantic sea surface temperature. This will be done my examining observational data and looking for physical mechanisms responsible.
OUTCOMES: Found that the observed trend in fall precipitation is consistent with quasi-decadal (12 year) variations in the strength/location of the jet stream, changes in north Pacific storm tracks, and changes in meridional moisture flux into the US from the Gulf of Mexico. Models used have so far show weak fall precipitation signals.