The Role of Convective Intensity in Modulating Earth’s Radiative Balance

Abstract It has been suggested that deep convective vertical intensity may increase in regions that are becoming increasingly moist in response to warming sea surface temperatures, with corresponding impacts on anvil cloud development and their top-of-atmosphere radiative effects. This work seeks to document the observed relationships between convective core intensity and cloud optical thickness and altitude that are the primary drivers of how high clouds fundamentally influence Earth’s radiative energy budget. We employ a database of “convective objects” generated from 10 years of A-Train measurements to explore such relationships over the tropical ocean. In general, active convection has a negative net cloud radiative effect (CRE) over the tropical ocean regions. When sorting deep convective systems by a radar-based proxy for core intensity, the predominant radiative response is an increase in longwave (LW) CRE as cloud-top heights increase with intensity. Meanwhile, thin cirrus increases at the expense of thicker anvil cloud, which weakens the shortwave (SW) CRE for systems composed of mostly thin cloud. This offsets enhanced SW CRE in thicker cloud systems driving the ensemble of convective systems toward a more neutral net radiative effect at the top of the atmosphere as intensity increases. Significance Statement Studies suggest that the intensity of atmospheric deep convection might change in a changing climate, which could alter how deep convective clouds influence Earth’s energy budget. On average, the convective systems observed cool at the top of the atmosphere, but each individual system has largely differing cloud properties and energetic contributions. The most intense convective systems have a near-neutral or small cooling effect owing to higher cloud-top heights compared to less intense systems that have a much larger cooling effect. The ratio of thick to thin cloud amount helps explain the spread in the energy budget contributions by the most intense systems. Systems primarily composed of thick cloud have a cooling impact, while thin cloud systems contribute a warming. Finally, it is important to consider total energetic contribution when both high and low clouds are present, as they more often contribute a warming impact compared to systems with just high cloud.