Study of cloud and climate modification caused by global scale air pollution

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(1) NOAA/AVHRR LAC data sets were purchased and analyzed for retrieving cloud and aerosol microphysical parameters. We have developed an algorithm for getting cloud optical thickness and effective particle radius by making use of AVHRR channel 1,3 and 4 radiances. We also developed an algorithm for retrieving aerosol optical characteristics from AVHRR channel 1 and 2 and GMS band 1.(2) We have found examples of cloud modifications over areas such as the western coastal region of the North American Continent, the Amazon area, the Yellow Sea area, and the western coastal region of the African Continent. General characteristics for the modifications are that the clouds in the continental air mass have large liquid water path and small effective particle radius ; the clouds in the maritime air mass have small liquid water path and large effective particle radius.(3) The effect of the obtained cloud modification on climate has been estimated by a simple energy budget model. We found a cloud … More system which has drizzle particles can cool the climate system effectively.(4) We have developed an accurate yet efficient radiation code which can treat scattering/absorption/emission processes by clouds and aerosols as well as absorption/emission by gaseous constituents. This code has been successfully implemented into our numerical climate model.(5) In order to improve our description and prediction ability of radiative convective equilibrium states, the thermal convection theory of Boussinesq fluid is reconsidered aiming at constructing a basic theory for radiative convection which should replace the current theory basically developed for Benard convection. The focus is placed on examine the difference in the appearance of circulation structures caused by thermal conditions imposed to the system. Numerical calculations of two dimensional fluid show that the wavenumber one circulation structure and asymmetry of upward and downward motions, which are the characteristics considered generic to the moist convection, widely appear in the convection driven by internal cooling in general. Those features are also recognized in the calculations of three dimensional spherical convection. Less