Sensitivity of tropical rainfall to Banda Sea Diffusivity in the Community Climate System Mode

The experiments described in this paper show that increasing the background diffusivity in the Banda Sea from the commonly used value of 0.1 cm s1 to the observed value of 1 cm2 s1 improves the watermass properties there by reproducing the observed thick layer of Banda Sea Water.

The resulting reduced sea surface temperatures lead to weaker convection and a redistribution of precipitation, away from the Indonesian seas toward the equatorial Indian and Pacific Oceans. In particular, the boreal summer precipitation maximum of the Indonesian seas shifts northward from the Banda Sea toward Borneo, which reduces a longstanding bias in the simulation of the Austral–Asian Monsoon in the Community Climate System Model.