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A Comparison of Cloud Microphysical and Optical Properties during TOGA-COAREThe impact of cirrus clouds on climate is an issue of research interest currently. Whether cirrus clouds heat or cool the Earth-atmosphere system depends on the cloud shortwave albedo and infrared reflectance and absorptance. These in turn are determined by the size distribution, phase, and composition of particles in the clouds. The TOGA-COARE campaign presented an excellent opportunity to study cirrus clouds and their influence on climate. In this campaign, a microphysics instrument package was flown aboard the DC-8 aircraft at medium altitudes in cirrus clouds. This package included a 2D Greyscale Cloud Particle Probe, a Forward Scattering Spectrometer Aerosol Probe, and an ice crystal replicator. At the same time the ER-2 equipped with a radiation measurement system flew coordinated flight tracks above the DC-8 at very high altitude. The radiation measurement made were short and long wave fluxes, as well as narrowband fluxes, both upwelling and downwelling. In addition LIDAR data is available. The existence of these data sets allows for a the comparison of radiation measurement with microphysical measurements. For example, the optical depth and effective radius retrieved from the ER-2 radiation measurements can be compared to the microphysical data. Conversely, the optical properties and fluxes produced by the clouds can be calculated from the microphysical measurements and compared to those measured aboard the ER-2. The assumptions required to make these comparisons are discussed. Typical microphysical results show a prevalence of micron-sized particles, in addition to the cloud particles that exceed 100 mm. The large number of small particles or "haze" cause the effective cloud radii to shift to smaller sizes, leading to changes in optical parameters.
Document ID
20020038915
Document Type
Conference Paper
Authors
Strawa, A. W. (NASA Ames Research Center Moffett Field, CA United States)
Pueschel, R. F. (NASA Ames Research Center Moffett Field, CA United States)
Pilewskie, P. (NASA Ames Research Center Moffett Field, CA United States)
Valero, F. P. J. (Scripps Institution of Oceanography La Jolla, CA United States)
Gore, Warren J.
Date Acquired
August 20, 2013
Publication Date
January 1, 1996
Subject Category
Environment Pollution
Meeting Information
American Geophysical Union 1996 Spring Meeting(Baltimore, MD)
Funding Number(s)
PROJECT: RTOP 460-22-81-10
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.