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Climatology of contribution‐weighted tropical rain rates based on TRMM 3B42
Author(s) -
Venugopal V.,
Wallace J. M.
Publication year - 2016
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 - 10.1002/2016gl069909
Subject(s) - rain rate , precipitation , environmental science , climatology , rain gauge , tropics , meteorology , atmospheric sciences , geology , geography , fishery , biology
The climatology of annual mean tropical rain rate is investigated based on merged Tropical Rainfall Measuring Mission (TRMM) 3B42 data. At 0.25° × 0.25° spatial resolution, and 3‐hourly temporal resolution, half the rain is concentrated within only ∼1% of the area of the tropics at any given instant. When plotted as a function of logarithm of rain rate, the cumulative contribution of rate‐ranked rain occurrences to the annual mean rainfall in each grid box is S shaped and its derivative, the contribution‐weighted rain rate spectrum, is Gaussian shaped. The 50% intercept of the cumulative contribution R 50 is almost equivalent to the contribution‐weighted mean logarithmic rain rateR L¯ based on all significant rain occurrences. The spatial patterns of R 50 andR L¯ are similar to those obtained by mapping the fraction of the annual accumulation explained by rain occurrences with rates above various specified thresholds. The geographical distribution of R 50 confirms the existence of patterns noted in prior analyses based on TRMM precipitation radar data and reveals several previously unnoticed features.