RegT-Band: a tropical band version of RegCM4

We present RegT-Band, a tropical band version of the regional climate model RegCM4, and analyze a 5 yr simulation for the period 1998-2002 with observed sea-surface temperature (SST) and lateral boundary condition forcing. The domain extends from 50 degrees S to 50 degrees N and covers the entire tropics at a grid spacing of about 39 km, i.e. it includes lateral boundary forcing only at the southern and northern boundaries. RegT-Band captures the basic features of the tropical circulation and associated precipitation patterns. The most noticeable model deficiencies occur over the Indian Ocean, where the convective parameterization used presents some problems. Monsoon precipitation patterns over different regions are captured, although the model shows a tendency for an early onset of the Indian and northern Australian monsoon. The model also captures the ENSO signal on the precipitation anomaly patterns for the 1998 El Nino event compared to the 2000 La Ni a event. Although further testing is needed, this simulation shows encouraging results towards the use of RegT-Band for the study of tropical climate processes.