ANNUAL VARIATION OF RAINFALL OVER BRAZIL AND WATER-VAPOR CHARACTERISTICS OVER SOUTH-AMERICA

A large region in central Brazil is characterized by summer rainfall a nd winter dry conditions. During the 6-month period of September, Octo ber, November, December, January, and February (SONDJF) this region re ceives 70% or more of its annual rainfall. Calculations of vertically integrated water vapor flux and its divergence are made for South Amer ica. The results suggest that the Amazon basin is the principal source of moisture for central Brazil during the period SONDJF. Water vapor flux from the equatorial Atlantic associated with trade winds is the m ain moisture source for the Amazon basin.