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Title: Global survey of effective particle size in liquid water clouds by satellite observations

Abstract

A global survey of cloud particle size is needed for climate change studies. This can supply crucial information for parameterizing cloud optical properties on a global scale as well as to estimate variation in cloud liquid water content with environmental temperature. Cloud particle size is helpful in evaluating the effect of aerosol variations, which represents a major uncertainty in climate change studies. In this dissertation, a method for retrieving cloud particle size information on a global scale, using currently available satellite data from ISCCP (International Satellite Cloud Climatology Program), is described. Four months of data for the satellites NOAA-9 and NOAA-10 have been processed. A radiative transfer model is used to retrieve cloud particle size. The model includes the major absorbing gases as well as scattering absorption and emission by clouds in the computation of synthetic radiances for specified satellite viewing geometry. The model results have been validated against clear sky observations and are consistent with the observed radiance range under cloudy conditions. A method has been developed for estimating instrument noise and accounting for its effects on the analysis. Surface reflectance at 3.7 [mu]m has been retrieved globally, and its effect on cloud particle size has been considered. Errormore » sources and the range of their contributions are included for each cloud particle size. The results of this global survey reveal continental and maritime differences, hemispheric contrasts, seasonal and diurnal variations of effective droplet radii as well a relationship between cloud optical thickness and droplet size. The hemispheric contrasts are indicative of some impact of anthropogenic aerosols. The cloud droplet size variations with sea surface temperature in remote ocean areas suggest little effect of DMS (dimethylsulfide) aerosols. The survey makes it possible to retrieve cloud liquid water path information over land.« less

Authors:
Publication Date:
Research Org.:
Columbia Univ., New York, NY (United States)
OSTI Identifier:
7018003
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CLOUDS; GLOBAL ASPECTS; PARTICLE SIZE; REMOTE SENSING; AEROSOLS; ATMOSPHERIC CHEMISTRY; CLIMATIC CHANGE; METEOROLOGY; SATELLITES; CHEMISTRY; COLLOIDS; DISPERSIONS; SIZE; SOLS; 540120* - Environment, Atmospheric- Chemicals Monitoring & Transport- (1990-)

Citation Formats

Han, Qingyuan. Global survey of effective particle size in liquid water clouds by satellite observations. United States: N. p., 1992. Web.
Han, Qingyuan. Global survey of effective particle size in liquid water clouds by satellite observations. United States.
Han, Qingyuan. 1992. "Global survey of effective particle size in liquid water clouds by satellite observations". United States.
@article{osti_7018003,
title = {Global survey of effective particle size in liquid water clouds by satellite observations},
author = {Han, Qingyuan},
abstractNote = {A global survey of cloud particle size is needed for climate change studies. This can supply crucial information for parameterizing cloud optical properties on a global scale as well as to estimate variation in cloud liquid water content with environmental temperature. Cloud particle size is helpful in evaluating the effect of aerosol variations, which represents a major uncertainty in climate change studies. In this dissertation, a method for retrieving cloud particle size information on a global scale, using currently available satellite data from ISCCP (International Satellite Cloud Climatology Program), is described. Four months of data for the satellites NOAA-9 and NOAA-10 have been processed. A radiative transfer model is used to retrieve cloud particle size. The model includes the major absorbing gases as well as scattering absorption and emission by clouds in the computation of synthetic radiances for specified satellite viewing geometry. The model results have been validated against clear sky observations and are consistent with the observed radiance range under cloudy conditions. A method has been developed for estimating instrument noise and accounting for its effects on the analysis. Surface reflectance at 3.7 [mu]m has been retrieved globally, and its effect on cloud particle size has been considered. Error sources and the range of their contributions are included for each cloud particle size. The results of this global survey reveal continental and maritime differences, hemispheric contrasts, seasonal and diurnal variations of effective droplet radii as well a relationship between cloud optical thickness and droplet size. The hemispheric contrasts are indicative of some impact of anthropogenic aerosols. The cloud droplet size variations with sea surface temperature in remote ocean areas suggest little effect of DMS (dimethylsulfide) aerosols. The survey makes it possible to retrieve cloud liquid water path information over land.},
doi = {},
url = {https://www.osti.gov/biblio/7018003}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1992},
month = {Wed Jan 01 00:00:00 EST 1992}
}

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