Cloud type and top height estimation for tropical upper-tropospheric clouds using GMS-5 split-window measurements combined with cloud radar measurements

Abstract

Cloud types of tropical upper-tropospheric stratiform clouds (UTSCs) were estimated using split-window brightness temperatures (TB) measured by a geostationary satellite. For non-precipitating high clouds, cloudtop heights were estimated. Observation-based estimation tables in terms of 10.8 μm TB (T11) and the difference between T11 and 12 μmTB (ΔT = T11 - T12) 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 T11 and ΔT. The detectability of non-precipitating UTSCs is higher in regions with T11 between 220 and 275 K and higher ΔT. Surface precipitation is more detectable in regions with low T11 and small ΔT. The estimated cloud-top height of nonprecipitating UTSCs tends to rise with decreasing T11 and increasing ΔT. The variation in the cloud-top estimates with ΔT reached a few kilometers at T11 of ~250 K.