The observed variation in cloud-induced longwave radiation in response to sea surface temperature over the Pacific warm pool from MTSAT-1R imagery

摘要

[1] 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., DOLR, DSST; 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(DSST_(clear)). The estimated value of DOLR/DSST_(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)). Citation: Cho, H., C.-H. Ho, and Y.-S. Choi(2012), The observed variation in cloudinduced longwave radiation in response to sea surface temperature over the Pacific warm pool from MTSAT-1R imagery, Geophys. Res. Lett., 39, L18802, doi:10.1029/2012GL052700.