HR: 1340h
AN: A43B-0079    [Abstracts]
TI: Using the NPOESS Aerosol Polarimetry Sensor to Retrieve Cloud Environmental Data Records
AU: Sato, M
EM: pdmrs@kyoto.giss.nasa.gov
AF: SGT Inc., 2880 Broadway, New York, NY 10025 United States
AU: * Cairns, B
EM: bc25@columbia.edu
AF: Columbia University, 2880 Broadway, New York, NY 10025 United States
AU: Travis, L
EM: ltravis@giss.nasa.gov
AF: NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 United States
AB: The magnitude and relative strengths of the mechanisms that cause the indirect effect of aerosols on clouds are amongst the most uncertain aspects of the radiative forcing of climate. The three primary cloud properties that are indicative of aerosol effects on clouds are the cloud droplet concentration and the location (effective radius) and width (effective variance) of the cloud droplet size distribution. In this paper we show how passive polarimetric measurements can be used to estimate the number concentration of droplets in clouds, vertical profiles of effective radius, effective variance, cloud physical thickness and cloud top height. The passive polarimetric measurements that we use in this analysis will be available from the planned NPOESS Aerosol Polarimetry Sensor (APS). Currently passive satellite measurements provide estimates of effective radius and effective variance, if the cloud is sufficiently physically extensive. New active sensors will provide vertical profiles of effective radius and estimates of the number concentration of droplets. The advantage of the APS measurements is that they can provide all three cloud properties that are needed to diagnose and estimate the magnitude of the indirect effect of aerosols on clouds, on an operational basis, for all clouds that are observed.
DE: 0319 Cloud optics
DE: 0321 Cloud/radiation interaction
DE: 3311 Clouds and aerosols
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005