Discrepancies in Different Precipitation Data Products in the Bay of Bengal during Summer Monsoon Season

Abstract EN

In the east Bay of Bengal (BoB), the precipitation maximum always lies near the eastern coast on the windward side of Mountain Araka Yoma in the summer monsoon season.

In this study, different precipitation products are compared in terms of their representation of the offshore rainfall maximum feature in this region.

Climatologically, all products examined present similar rainfall distribution except for the CMAP.

Significant discrepancies among different products are found in the interannual variation, as illustrated by the contrast features between 2002 and 2005.

Based on the TRMM products (except for 3B42RT) and GPCP V1.2, the precipitation maximum occurred near the coast in 2002, while it was about 100–200 km offshore in 2005.

However, this difference is not obvious in the GPCP V2.2 and TRMM 3B42RT products.

Larger easterly vertical wind shear and warmer SST were present in 2005.

Both favor stronger orographically-forced convective systems to propagate offshore, leading to the offshore rainfall maximum in 2005.

Therefore, it is suggested that the TRMM 3B40RT, which is mainly based on passive microwave estimates, may be more reliable among different precipitation products in reflecting the precipitation feature in the coastal region of the east BoB.