HR: 16:45h
AN: A52G-04    [PDF]
TI: Cloud Structure Over Tropical Pacific During 1985--1999: Preliminary Analysis
AU: * Wang, P
EM: p.wang@larc.nasa.gov
AF: STC/NASA-LaRC, MS 475, Hampton, VA 23681-2199 United States
AU: Cess, R D
EM: rcess@notes.cc.sunysb.edu
AF: Marine Sciences Research, State University of New York, Stony Brook, Stony Brook, NY 11794-5000 United States
AU: Wong, T
EM: takmeng.wong@larc.nasa.gov
AF: NASA-LaRC, MS 420, Hampton, VA 23681-2199 United States
AU: Minnis, P
EM: p.minnis@larc.nasa.gov
AF: NASA-LaRC, MS 420, Hampton, VA 23681-2199 United States
AU: Kent, G S
EM: g.s.kent@larc.nasa.gov
AF: STC/NASA-LaRC, MS 475, Hampton, VA 23681-2199 United States
AB: SAGE II observations from 1985 to 1999 during the month December--April are used to infer cloud vertical structure over tropical Pacific with the focus on two specific regions of climate sensitivity, namely, the Pacific warm pool (WP; 5$^{\circ}$S-10$^{\circ}$N, 100$^{\circ}$E-170$^{\circ}$E) and the Eastern Pacific (EP; 7.5$^{\circ}$S-7.5$^{\circ}$N, 200$^{\circ}$E-280$^{\circ}$E). Cloud distributions over these two geographic regions are closely linked through large scale circulation systems, particularly the Walker circulation. SAGE II cloud data have been used to study tropical cloud characteristics associated with the strong 1997/1998 El Ni\~no. It was shown that, with respect to normal years, both opaque cloud (OC) and subvisual cloud (SVC) are enhanced over the EP and weakened over the WP as consistent with outgoing radiation observations from satellite instruments. The objectives of the present study are to explore the long-term behavior of the cloud structure over the WP and EP, and to study the relationship of cloud properties between these two areas. The preliminary results from the present analysis indicate that the opaque cloud occurrence over the WP declined during 1986/87, 1989/90, 1994/95, and 1997/98, with opposite changes over the EP, except in 1994/95. These interannual opaque cloud variations appear to be the manifestation of large scale circulation changes in the Tropics in response to El Ni\~no events. In the case of subvisual cloud, the interannual variation over the EP closely resembles that of the opaque cloud in the same area. Over the WP, such a resemblance is much less evident, except from 1996 to 1999.
DE: 3314 Convective processes
DE: 3374 Tropical meteorology
DE: 3399 General or miscellaneous
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting