A hybrid bispectral threshold method (HBTM) is developed for hourly regional cloud and radiative parameters from geostationary satellite visible and infrared radiance data. The quantities derived with the HBTM include equivalent blackbody temperatures for clear skies, for the total cloud cover and for the cloud cover at three levels in the atmosphere; the total fractional cloud cover and the fractional cloud amounts at three altitudes; and the clear-sky and total cloud reflectance characteristics. Geostationary satellite data taken during November 1978 are analyzed. A minimum reflectance technique is used to determine clear-sky brightness. A visible bidirectional reflectance model is derived for clear ocean areas. Clear-sky radiative temperature is found with a bispectral clear radiance technique during daylight hours. An empirical model is derived to predict clear-sky temperature at night. A combination of previously published infrared threshold and bispectral techniques is used to determine the...

Diurnal Variability of Regional Cloud and Clear-Sky Radiative Parameters Derived from GOES Data. Part I: Analysis Method

A brief review of observations of clouds using satellites highlights open issues and directions for future studies. The key one is improved treatment of the effects of small-scale spatial inhomogeneity in remote sensing data analyses and in the treatment of radiation in climate models, though studies and observations of the spectral dependence of cloud-radiation interactions are also limited. Significant progress in understanding the role of clouds in climate, especially regarding cloud-radiation budget relationships, is expected in the next several years because of an unprecedent suite of global and regional observation and analysis programs.

Measuring cloud properties from space: a review

A comparative study of cloud classification techniques

A method for deriving cloud top heights using satellite remote temperature sounding instruments is described. The weighting functions of a 15μm CO2 tropospheric temperature sounder are modified by the presence of cloud in the sounding column. The relative effect of cloud on two or more such weighting functions in successive soundings along an orbital or scanning track is shown to be a simple function of cloud height. The method permits cloud heights to be found without the need to derive cloud amount. Results from the Nimbus 5 Selective Chopper Radiometer are presented.

Cloud top heights from temperature sounding instruments

Statistical measures of the spatial distributions of gray levels (cloud reflectivities) are determined for LANDSAT Multispectral Scanner digital data Textural properties for twelve stratocumulus cloud fields, seven cumulus fields, and two cirrus fields are examined using the Spatial Gray Level Co-Occurrence Matrix method The co-occurrence statistics are computed for pixel separations ranging from 57 m to 29 km and at angles of 0°, 45°, 90° and 135° Nine different textual measures are used to define the cloud field spatial relationships However, the measures of contrast and correlation appear to be most useful in distinguishing cloud structure Cloud field macrotexture describes general cloud field characteristics at distances greater than the size of typical cloud elements It is determined from the spatial asymptotic values of the texture measures The slope of the texture curves at small distances provides a measure of the microtexture of individual cloud cells Cloud fields composed primar

Marine Stratocumulus Cloud Fields off the Coast of Southern California Observed Using LANDSAT Imagery. Part II: Textural Analysis

A simple objective technique is presented that integrates satellite-measured infrared radiation temperatures with the National Meteorological Center objective temperature analysis to yield cloud height and amount classification for small grid squares. Sample of cloud information obtained by this technique from ITOS 1 data over the United States show good agreement with cloud observations obtained by surface observers and from aircraft reports. The method is completely automated and can be used to produce cloud analyses on a global scale.

A. G. DeCOTIIS

Papers

A Procedure for Estimating Cloud Amount and Height From Satellite Infrared Radiation Data