Impact and Variability of Cloud Types on Earth's Top‐of‐Atmosphere Energy Balance in the Tropics: A 19‐Year Analysis of High‐Resolution CERES Data

Abstract Cloud radiative effects (CREs) play a critical role in Earth's energy balance and climate variability, yet the variability and specific contributions of distinct cloud types remain poorly understood. Using the Clouds and the Earth's Radiant Energy System FluxByCldTyp data set, this study investigates how temporal variations in total top‐of‐the‐atmosphere CREs are influenced by changes in the physical properties and fractional coverages of 42 individual cloud types and their broader categories over a 19‐year period. The analysis spans the tropical belt (25°S–25°N) and several convectively active regions, including the Tropical Western Pacific (TWP) and Africa. Our results show that variability in total CREs is primarily driven by changes in cloud fraction rather than microphysical properties. High clouds—particularly cirrostratus and deep convective clouds—exert strong negative correlations with shortwave CREs and strong positive correlations with longwave CREs, with correlation magnitudes reaching ±0.90 in the TWP. Low clouds, especially shallow cumulus, exhibit opposite correlations, partly due to obscuration by upper‐level clouds. While properties like total cloud water path, optical depth, and particle size influence cloud type‐mean CREs, their correlations with total CRE are relatively weak and largely due to co‐variability with total cloud amount. These correlations are generally more distinct and stronger within regional domains than across the tropical mean. Additionally, strong interrelationships are found among cloud categories, with high and low clouds often varying inversely. These results underscore the importance of cloud type‐specific contributions to radiative budget variability, providing observational benchmarks for climate model evaluation and cloud feedback studies.