CAREER: Investigation of the Scattering and Radiative Properties of Ice and Mixed-Phase Clouds

Texas A&M Research Foundation, College Station TX

Investigators

Abstract

The goal of this project is to improve the treatment of ice and mixed-phase clouds in remote sensing applications and in the parameterization of clouds for climate and general circulation models. The research consists of five broad components. Principal of these is a fundamental investigation of light scattering by nonspherical ice particles, including crystals of regular and irregular shapes characteristic of cirrus clouds and clouds composed of a mix of ice crystals and supercooled water droplets. This work centers on improving the accuracy and efficiency of scattering computations by using a combination of the finite-difference time domain (FTDT) method, T-matrix methods, and the improved geometric optics method (IGOM). The objective is to generate a data base for absorption and scattering properties of various ice crystal forms at solar and infrared wavelengths. The other research components include (1) integration of the scattering results for individual particles with information of the composition of cirrus clouds to determine the radiative properties of the clouds for the purposes of satellite remote sensing; (2) parameterization of the bulk radiative properties of cirrus and mixed-phase clouds for application to large-scale atmospheric models; (3) development of retrieval algorithms for inferring cloud microphysical and optical properties from multispectral satellite measurements; (4) integration of the light scattering programs, radiative transfer schemes, and retrieval algorithms in a convenient computational package for the remote sensing and climate modeling communities. Along with graduate and undergraduate student supervision, the educational component of the project comprises developing a curriculum that integrates radiative transfer, cloud physics, and atmospheric remote sensing, and ultimately establishing a Laboratory for Radiative Transfer and Remote Sensing, including web-based instructional material.