Tuesday, 11 February 2003
Comparing TRMM rain characteristics and lightning in West Africa for a La Nina year (1999) verses and El Nino Year (2002)
During a typical El Nino year, rain rates in West Africa are generally lower in association with weaker 200 mb winds (Tropical Easterly Jet) while the converse is true during La Nina conditions. During 1999 when cold SST anomalies were found in the Tropical Pacific and rain rates in West Africa were near to above normal. The launch of the TRMM satellite enables the examination of rain characteristics (stratiform/convective rain fractions, stratiform/convective heights) in addition to rain rate estimates. Hence rain rates and characteristics are examined along with lightning flash rates and flash totals from the Lightning Imaging Sensor (LIS) during the wet season (May-September) in West Africa. Moreover, differences in the Tropical Easterly Jet, African Easterly Jet, upper/middle troposphere and middle/lower troposphere shear are examined for 1999 and 2002.