Evaluation of the Tropical Rainfall Measuring Mission (TRMM) 3B42 and
3B43 products relative to Synoptic Weather Station Observations over
Cameroon
Abstract
The Tropical Rainfall Measuring Mission (TRMM) daily (3B42) and monthly
(3B43) rainfall products are evaluated relative to synoptic weather
station observations in Cameroon and according to the main agro-climatic
regions. In order to achieve this goal, deterministic and categorical
metrics were used, as well as inter annual variability and seasonnal
distributions. Outcomes of the comparison showed that synoptic weather
station data are strongly correlated with the TRMM 3B43 data and that
rainfall distribution is characteristic for each agro-climatic region.
The highest skill scores were observed in the Sudano-sahelian, High
Savannah, and Western Highlands zones, while the Uni-modal Equatorial
zone displayed the lowest correspondence scores between TRMM rainfall
estimates and station-based observations. Daily TRMM 3B42 showed good
performance in detecting rainy events, especially for light and moderate
intensity rainfall events. TRMM 3B42 overestimates rainfall intensities
except in the uni-modal region where rainfall intensities are
underestimated. Rainfall seasonnality, as well convective zone are well
reproduced by the TRMM datasets. Overall, the skill of TRMM 3B42
decreases for increasing precipitation intensities.