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Reduced precipitation over large water bodies in the Brazilian Amazon shown from TRMM data
Author(s) -
Paiva Rodrigo Cauduro Dias,
Buarque Diogo Costa,
Clarke Robin T.,
Collischonn Walter,
Allasia Daniel Gustavo
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl045277
Subject(s) - amazon rainforest , precipitation , amazonian , environmental science , climatology , morning , atmospheric sciences , meteorology , geography , geology , ecology , biology , medicine
Tropical Rainfall Measurement Mission (TRMM) data show lower rainfall over large water bodies in the Brazilian Amazon. Mean annual rainfall ( P ), number of wet days (rainfall > 2 mm) ( W ) and annual rainfall accumulated over 3‐hour time intervals ( P 3 hr ) were computed from TRMM 3B42 data for 1998–2009. Reduced rainfall was marked over the Rio Solimões/Amazon, along most Amazon tributaries and over the Balbina reservoir. In a smaller test area, a heuristic argument showed that P and W were reduced by 5% and 6.5% respectively. Allowing for TRMM 3B42 spatial resolution, the reduction may be locally greater. Analyses of diurnal rainfall patterns showed that rainfall is lowest over large rivers during the afternoon, when most rainfall is convective, but at night and early morning the opposite occurs, with increased rainfall over rivers, although this pattern is less marked. Rainfall patterns reported from studies of smaller Amazonian regions therefore exist more widely.