Publication Abstracts

Han 1992

Han, Q., 1992: Global Survey of Effective Particle Size in Liquid Water Clouds by Satellite Observations. Ph.D. thesis. Columbia University.

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, a relationship that has been suggested as being important for climate feedback. Cloud particle size is also helpful in evaluating the effect of aerosol variations (both anthropogenic and natural), which represents another 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 µm 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 retrieved 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 as existence of a relationship between cloud optical thickness and droplet size. The hemispheric contrasts are indicative of some impact of anthropogenic aerosols. However, the cloud droplet size variations with sea surface temperature in remote ocean areas suggest little effect of DMS (dimethylsulfide) aerosols. The average liquid water path retrieved by this method is consistent with microwave measurement analyzed by other authors over ocean areas. The present survey makes it possible to retrieve cloud liquid water path information over land.

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BibTeX Citation

  author={Han, Q.},
  title={Global Survey of Effective Particle Size in Liquid Water Clouds by Satellite Observations},
  school={Columbia University},
  address={New York, N.Y.},

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RIS Citation

ID  - ha06010m
AU  - Han, Q.
PY  - 1992
BT  - Global Survey of Effective Particle Size in Liquid Water Clouds by Satellite Observations
PB  - Columbia University
CY  - New York, N.Y.
ER  -

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