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, cloud-top heights were estimated. Observation-based estimation tables in terms of 10.8 µm TB (T11) and the difference between T11 and 12 µm TB (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 non-precipitating 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.
2008 by the Meteorological Society of Japan