Revisiting the Land-Ocean Contrasts in Deep Convective Cloud Intensity Using Global Satellite Observations

Tropical convection tends to be more intense over land than ocean, but why? Numerous previous studies have investigated the causes of this difference. This paper revisits this question using CloudSat data and focuses on interconnecting various environmental parameters and cloud properties, which have often been examined in a piecemeal way in the past. Our analysis shows that if convection is treated as a process by which potential energy (convective available potential energy) is converted to kinetic energy (vertical velocity), then the conversion is more efficient over land than ocean. A key factor that affects this conversion efficiency is the lifting condensation level (LCL). Higher LCLs over land give rise to broader dry boundary layer thermals that transition to wider deep convective cores. Wider cores, in turn, are better protected from the dilution by entrainment, thus leading to stronger updrafts. This study highlights the importance of the dry stage of convection.