Monday, 15 January 2007
The role of moisture transport from oceans in global water balance and in West Africa precipitation
Exhibit Hall C (Henry B. Gonzalez Convention Center)
Moisture transport integrated over the depth of the atmosphere has been estimated over global oceans using measurements from spacebased microwave scatterometers and radiometers. The divergence of the transport has been compared with evaporation-precipitation estimated from microwave radiometers, from intrasseasonal to interannual time scales. This ocean-atmosphere water exhanges is equivalent to the total moisture transport across the coastline from ocean to land; its difference with the mass change estimated from GRACE in the monthly time scale, provides a check on global river discharge from land to ocean. The high-resolution moisture transport from the Atlantic and the Gulf of Guinea reveals that their seasonal difference is a possible cause of the abrupt change of maximum rainfall from July to September in the Soudano-Sahel region of West Africa, in additional to the prevalent theory based on westward propagation of synoptic mesoscale convective systems over land.