*Kuan-Man Xu1, Moguo Sun2, Yaping Zhou3
(1.NASA Langley Research Center, 2.Analytical Mechanics Associates, Inc./NASA Langley Research Center, 3.University of Maryland, Baltimore County)
Keywords:Cloud radiative effects, Tropical cloud properties, Cloud type
Land and oceanic convection exhibit significant contrasts in intensity and entrainment, but the impacts of these differences on the properties of other cloud types remain unclear. This study examines 19-yrs mean cloud properties and their radiative effects (CREs) by cloud type, with a focus on regional variations across convectively active tropical regions. Forty-two cloud types are classified based on cloud top pressure and optical depth. The analysis reveals distinct regional differences in cloud distribution, with oceanic regions dominated by upper-tropospheric anvils and boundary-layer clouds, which have higher water contents, while land regions feature higher fractions of mid-level clouds with lower liquid water contents. The study further explores top of atmosphere (TOA) shortwave (SW), longwave (LW) and net CREs, decomposing the contributions of individual cloud types to overall CRE deviations from tropical means into three components: deviations in CRE, cloud fraction (CF), and both combined. Results show that CF deviations play a dominant role in the decomposition, with mid- and high-level clouds enhancing LW warming and SW cooling, while low-level clouds reduce SW and net cooling. Although the CRE deviation component is much smaller than the CF deviation component for individual cloud types, its collective contribution to overall regional CRE differences, particularly for net CRE, is more comparable. This is attributed to opposing effects between low- and high-level clouds in the CF deviation component, while the CRE deviation component exhibits consistent regional differences across all cloud types. The decomposition analysis also highlights significant regional variations driven by land-ocean contrasts and meteorological forcings.