The Response of the effective static stability in the subtropics to MJO-induced tropical diabatic heating

The moist static energy (MSE) budget has been successfully used to understand and model moist convection in the deep tropics (e.g., Neelin 2007). Its application to the subtropics, however, where synoptic energy fluxes are non-negligible, is less straightforward. In this study, we use 6 hourly ERA-40 interim data to compute the diabatic heating field as the residual of the energy equation and we investigate how MJO-induced diabatic heating affects the effective static stability in the subtropics. We specifically focus on the linear response of Rossby waves, which radiate to the northeast of the diabatic heating and induce subsidence to the northwest. Preliminary results suggest that the subtropical effective static stability decreases downstream and increases upstream of the diabatic heating. In general, we find that relatively longer waves tend to increase the effective static stability in the subtropics. We apply our analysis to investigate how monsoon depressions over the Bay of Bengal and the subtropical Western Pacific respond to the MJO-induced diabatic heating.