HR: 16:45h
AN: A34D-04    [Abstracts]
TI: Cloud Structure Anomalies Over Tropical Pacific During 97/98 El Nino
AU: * Sun, M
EM: moguosun@gmail.com
AF: Science Systems and Applications, Inc, 1 Enterprise Pkwy, Suite 200, 1 Enterprise Pkwy, S, VA 23666, United States
AU: Cess, R D
EM: cess@atmsci.msrc.sunysb.edu
AF: Stony Brook University, SoMAS, Stony Brook University, Stony Brook, NY 11794, United States
AB: A merged satellite data set has been used to study cloud structure and outgoing longwave radiation (OLR) changes over the tropical Pacific Ocean during the strong 1997/98 El Niño. This data set provides radiative fluxes at the top of the atmosphere in addition to cloud fraction, cloud-top altitude and cloud optical depth, all on a one-degree by one-degree grid and as monthly means for the first eight months of 1998. This time period includes much of the 1997/98 El Niño, which reached peak intensity in March 1998 and had essentially subsided by August 1998. The west-to-east shift of the center of convection that occurred during the El Niño resulted in cloud fraction, cloud-top altitude and cloud optical depth all increasing in the eastern equatorial Pacific while decreasing in the western tropical Pacific, and for both regions all three cloud parameters are strongly correlated with each other. OLR changes over the eastern Pacific are also investigated. For all sky OLR change, though highly correlated with sea surface temperature (SST), is mainly driven by cloud altitude and cloud fraction change. Clear sky OLR change is mainly due to moisture change. SST and lapse rate have much smaller effect on OLR change.
DE: 0321 Cloud/radiation interaction
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting