Cloud Type and Top Height Estimation for Tropical Upper-Tropospheric Clouds Using GMS-5 Split-Window Measurements Combined with Cloud Radar Measurements

Cloud types of tropical upper-tropospheric stratiform clouds (UTSCs) were estimated using split-window brightness temperatures (In) measured by a geostationary satellite. For non-precipitating high clouds, cloudtop heights were estimated. Observation-based estimation tables in terms of 10.8 mu m T-B (T-11) and the difference between T-11 and 12 mu m T-B (Delta T = T-11 - T-12) were presented using ship-borne cloud radar measurements conducted during three months in the tropical warm-pool region. After defining the cloud types and cloud-top height using radar measurements, their detectabilities were shown as the function of T-11 and Delta T. The detectability of non-precipitating UTSCs is higher in regions with T-11 between 220 and 275 K and higher Delta T. Surface precipitation is more detectable in regions with low T-11 and small Delta T. The estimated cloud-top height of non-precipitating UTSCs tends to rise with decreasing T-11 and increasing Delta T. The variation in the cloud-top estimates with Delta T reached a few kilometers at T-11 of similar to 250 K.