Diurnal Variation of Precipitation from NASA Satellites and Goddard MMF

The diurnal cycle is a fundamental mode of atmospheric variability and has a major impact on weather and climate prediction. In addition, it provides a robust test of physical processes represented in atmospheric models that are used for studying the water and energy cycles. Most climate models simulate precipitation too early over both land and ocean.

Distribution of the local solar time (LST)
of precipitation frequency maximum over land and ocean

NASA satellite retrievals in general show that precipitation occurs most frequently in the late afternoon and early morning over major continents and oceans, respectively. The Goddard Multi-scale Modeling Framework (MMF) that replaces the sub-grid cloud parameterization with an explicit cloud-resolving model, is superior to the Goddard fvGCM (a convectional climate model) in reproducing the correct timing of the diurnal cycle of precipitation frequency both over lands and oceans.