The Diurnal Cycle of Rainfall in the Tropics
The tropics receives a strong diurnal cycle in incoming solar radiation throughout the year, driving the diurnal cycle of cloudiness and rainfall. The above figure shows that a large percentage of rainfall variability in the tropics is explained by the diurnal variability. Despite the importance of the diurnal cycle, the mechanism behind the diurnal cycle of cloudiness and rainfall over the open tropical oceans is not completely understood. Current climate and weather models also struggle to accurately capture the diurnal cycle of cloudiness and rainfall in the tropics.
My research focuses on observing the characteristics of the diurnal cycle of rainfall and cloudiness and how they vary with large-scale tropical disturbances (e.g., the Madden-Julian Oscillation, convectively-coupled equatorial waves, and ENSO). As an example, the above schematic illustrates significant variability in the diurnal cycle of the cloud population and rainfall associated with the MJO over the open tropical ocean. The changes in the diurnal cycle are driven by complicated interactions between clouds, radiation, and moisture. Examination of these interactions between the diurnal cycle and large-scale disturbances provides insights into the mechanisms of how individual clouds develop and decay, and how such mechanisms are altered by large-scale disturbances.