HR: 0800h
AN: A51A-0009    [Abstracts]
TI: Satellite and Radar Characteristics of Drizzling Marine Stratocumulus in the Southeast Pacific
AU: * Yuter, S
EM: sandra_yuter@ncsu.edu
AF: North Carolina State University, Dept. of Marine, Earth, and Atmospheric Sciences Campus Box 8208, 1125 Jordan Hall, Raleigh, NC 27695
AU: Comstock, K
EM: kcomstock@atmos.washington.edu
AF: University of Washington, Department of Atmospheric Sciences Box 351640, Seattle, WA 98195
AB: Marine stratocumulus clouds have long been recognized as providing significant cooling over large regions of the subtropical ocean. Typical stratocumulus (Sc) sheets consist of a combination of closed-cellular or unbroken and open-cellular cloud patterns with different radiative characteristics. Recent field studies have revealed that significant drizzle from marine Sc clouds in the northeast and southeast Pacific is more frequently associated with the open-cellular cloud structure and less often associated with closed-cellular clouds. This analysis uses data collected during the EPIC Sc 2001 field study in the southeast Pacific to quantify relationships among cloud and drizzle characteristics. Data sets include a shipboard scanning C-band radar as well as VIS and IR geosynchronous satellite data. Although the EPIC Sc sample is limited to 6 days, it represents the best documentation of the areal characteristics of marine Sc drizzle obtained in field projects to date. Satellite images are used to segregate data into time periods with open or closed-cellular cloud structure or a transition category. Drizzle was found to be strongly modulated by the diurnal cycle as well as the cloud structure. The pdf of drizzle rates for closed and open-cellular clouds overlapped, but generally the highest areal-mean rain rates were associated with the open cells. The implications for application of these findings to satellite data over longer time periods and to a larger area of the southeast Pacific are discussed.
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005