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The observed variation in cloud‐induced longwave radiation in response to sea surface temperature over the Pacific warm pool from MTSAT‐1R imagery
Author(s) -
Cho Heeje,
Ho ChangHoi,
Choi YongSang
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2012gl052700
Subject(s) - longwave , sea surface temperature , outgoing longwave radiation , environmental science , climatology , atmospheric sciences , forcing (mathematics) , geostationary orbit , cloud forcing , convection , meteorology , radiative transfer , radiative forcing , geology , satellite , physics , aerosol , quantum mechanics , astronomy
This study investigated variations in outgoing longwave radiation (OLR) in response to changes in sea surface temperature (SST) over the Pacific warm pool area (20°N–20°S, 130°E–170°W). OLR values were obtained from recent (January 2008–June 2010) geostationary window channel imagery at hourly resolution, which resolves processes associated with tropical convective clouds. We used linear regression analysis with the domain‐averaged OLR and SST anomalies (i.e., Δ OLR , Δ SST ; deviations from their 90‐day moving averages). Results show that the regression slope appears to be significant only with SST least‐affected by cloud radiative forcing, for which SST needs to be obtained as daily average over cloud‐free regions (Δ SST clear ). The estimated value of Δ OLR /Δ SST clear is 15.72 W m −2 K −1 , indicating the presence of strong outgoing longwave radiation in response to surface warming. This atmospheric cooling effect is found to be primarily associated with reduced areal coverage of clouds (−14.4% K −1 ).