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 (T_B) 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 T_B (T₁₁) and the difference between T₁₁ and 12 µm T_B (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.