Paper No. 12 FOUR DIMENSIONAL OBSERVATIONS OF CLOUDS FROM GEOSYN- CHRONOUS ORBIT USING STEREO DISPLAY AND MEASUREMENT TECHNIQUES ON AN INTERACTIVE INFORMATION PROCESSING SYSTEM

Simultaneous Geosynchronous Operational Environmental Satellite (GOES) 1 km resolution visible image pairs can provide quantitative three dimensional measurements of clouds. These data have great potential for severe storms research and as a basic parameter measurement source for other areas of meteorology (e.g. climate). These stereo cloud height measurements are not subject to the errors and ambiguities caused by unknown cloud emissivity and temperature profiles that are associated with infrared techniques. Previous work by Minzner et al. (1978a) has demonstrated the validity of stereo measurements from geostationary satellites using techniques based on conventional analogue stereography. This effort describes the display and measurement of stereo data using digital processing techniques. Computer remapping of digital GOES image pairs allows the interactive display (on the Atmospheric and Oceanographic Information Processing System, AOIPS) of time sequences of stereo images : a true four dimensional representation of cloud structures. A description of similar work at the University of Wisconsin is given by Bryson (1978). Interactive manual and semi-automatic height measuring techniques have also been developed on AOIPS. Capabilities under development include: 1) measurement of multilevel wind fields with accurate height assignment; 2) estimation of thunderstorm intensity from horizontal and vertical cloud growth rates; and 3) measurement of four dimensional cloud structure for comparison with numerical models and radar observations. Stereo height verification and error analyses were conducted using computer crosscorrelation on AOIPS. Accuracies of -+0.5 km appear to be possible for geographical features and clouds with precisions (relative accuracies) approaching -+0.1 km.