On the Accuracy of the Moist Static Energy Budget when Applied to Large-Scale Tropical Motions

Abstract The moist static energy (MSE) budget is widely used to understand atmospheric thermodynamics. However, the not exact, and accuracy of approximations that yield it has been examined rigorously in context large-scale tropical motions (horizontal scales ≥ 1000 km). A scale analysis shows these are most accurate systems whose latent anomalies considerably larger than geopotential kinetic anomalies. This condition satisfied exhibit phase speeds horizontal winds on order 10 m s −1 or less. Results from a power spectral data DYNAMO field campaign ERA5 qualitatively agree with scaling, although they indicate neglected terms smaller what scaling suggests. linear regression MJO events occurred during yields results support findings. It suggested MSE tropics because within latitudes constrained small fluctuations as result weak temperature gradient (WTG) balance.