Accession Number:

ADA094119

Title:

Tests of Spectral Cloud Classification Using DMSP Fine Mode Satellite Data.

Descriptive Note:

Environmental research papers,

Corporate Author:

AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA

Personal Author(s):

Report Date:

1980-06-02

Pagination or Media Count:

44.0

Abstract:

A computer-based processor for satellite imagery was tested on samples of DMSP visible and IR imagery data smoothed to 0.6 n mi resolution. The data were displayed on the AFGL Man-computer Interactive Data Access System so that meteorologists could label small areas 25 x 25 n mi with one of nine possible cloud categories from the AF 3D Nephanalysis Program 3DNEPH. The computer-based processor labeled the same areas by computing a two-dimensional fast Fourier transform FFT and comparing the results to average wavenumber spectra for the cloud categories. Classification accuracies were 65 for visible, 65 for IR and 81 for combined data. The classification accuracies were appreciably better than chance and a simplified processor which used only the averaged values of satellite data over an area. Accuracies improved is some categories were merged. The results were also compared to a cloud typing procedure in the 3DNEPH and to some earlier studies. The results were generally good for categories with small-scale cloud features such as cumulus or cirrus clouds, but the overall accuracy of classification for all cloud categories was not significantly better than verifications cited in earlier studies. Two potential refinements to the spectral processors, namely, removing the effects of backgrounds such as land, water, and snow cover and minimizing sensitivity to varying fractional cloud cover from case to case, are also discussed. Author

Subject Categories:

  • Meteorology
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE