Water Vapor Characteristics over Northeast Brazil during Two Contrasting Years

Abstract

Water vapor characteristics over northeast Brazil for two contrasting years are discussed. During the wet year 1974, the precipitation efficiencies were less than 20% over the interior dry region and during the dry year 1976, they were reduced to 10% or less. The reduction is mainly due to low precipitation in 1976. Calculation of water vapor flux showed that in both wet and dry years, the flux is inward in the east sector and outward in the west sector. This suggests the importance of the South Atlantic Ocean in providing water vapor for NE Brazil. During the wet year, the lower tropospheric flow is convergent and in the northwest part, the direction of flow is more northerly/less southerly. During the dry year the opposite occurred. This indicates the possible role of the Intertropical Convergence Zone in the interannual variations of climate over NE Brazil.