Global Cloudiness and Cloud Top Information from AVHRR in the 42-Year CLARA-A3 Climate Data Record Covering the Period 1979–2020

This paper investigates the quality of global cloud fraction and cloud-top height products provided by third edition CM SAF cLoud, Albedo surface RAdiation dataset from AVHRR data (CLARA-A3) climate record (CDR) produced EUMETSAT Climate Monitoring Satellite Application Facility (CM SAF). Compared with CALIPSO–CALIOP lidar six other CDRs, including predecessor CLARA-A2, CLARA-A3 has improved detection, especially over ocean surfaces, geographical variation detection efficiency. In addition, exhibits remarkable improvements in accuracy its measurements. For example, tropical regions, previous underestimations for high-level clouds are reduced more than 2 km. By taking advantage realistic descriptions cloudiness, this study attempted to estimate trends observable low-level clouds, acknowledging their importance producing a net cooling effect. The results were generally inconclusive tropics, mainly due interference El Nino modes during period under study. However, analysis found small negative oceanic surfaces outside core region. Further studies needed verify significance these results.