COAMPS Extended-range Simulations in the Tropics
Comparison of the fixed and observed SST integrations indicate that the fixed SST has a small impact on the COAMPS precipitation and wind biases for the first two weeks, but has a substantial impact after that. Comparison of the 27-km and 45-km resolution experiments indicates that while the 27-km simulation outperforms the 45-km simulation for OLR, the advantages of higher resolution for other metrics are unclear. The 45-km simulation has smaller errors for the wind and precipitation fields. Examination of time-longitude diagrams of equatorial precipitation shows that the 45-km COAMPS simulation with observed SST has a remarkably good representation of the late-November Madden Julian Oscillation (MJO). The 45-km simulation with fixed SST, and the 27-km simulations, had weaker representations of the MJO. These results demonstrate the importance of accurate SSTs for predictions beyond “weather” time scales of 1-2 weeks.