A Cylindrical Cloud Model for Microwave and Infrared Radiative Transfer-Applications to Defense Meteorological Satellite Program Microwave Sounders.
Abstract
Analytical solutions to the thermal radiative transfer equation for one and two-dimensional cylindrical geometries for an isothermal cloud cylinder are derived using a truncated spherical harmonics expansion for the intensity and scattering phase function. Higher order approximations are generated by utilizing the recursion properties of the modified Bessel functions. Computational results are presented and physically discussed for a hypothetical atmosphere in the infrared 10 micron wavelength and in a realistic atmosphere in the microwave 50-60 GHz frequencies. Comparisons are made with a discrete-ordinate plane-parallel model and finite cubic and rectangular models in the infrared region and with a discrete-ordinate plane-parallel model in the microwave region. Results demonstrate that finite clouds have emissivities less than those of plane-parallel clouds and that optically thick cylindrical clouds should not be considered as black clouds. Further, the effect of the angle of observation of the satellite on remote sensing of a cloud pattern is demonstrated to be significant. Case studies are presented utilizing Defence Meteorological Satellite Program microwave sounder data along with standard meteorological data. Calculations for nonprecipitating and clear cases were similar and in good agreement with observations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1980
- Accession Number
- ADA092439
Entities
People
- Grant Clifford Aufderhaar
Organizations
- Air Force Institute of Technology