293 
FLOOD STRESS MAPPED NOAA-7 DATA 
Dee G. McCrary 
Department of: Commerce, NOAA/EDTS/CIAD 
AgRISTARS 
1050 Bay Area Blvd. 
Houston, Texas 77058 
T. I. Gray, Jr. 
NOAA/NESS/C&ESL 
AgRISTARS 
1050 Bay Area Blvd. 
Houston, Texas 
ABSTRACT 
NOAA-7 satellite data are used to map floods that occurred 
in North Texas during the Fall of 1981. In addition, 
runoff is detected as it enters the lakes. 
The Gray-McCrary Index, NOAA-n Channel 2-Channel 1, is used 
to map the flooded area by the use of a classifier which 
plots the index pixel-by-pixel for pre-determined I-J grid 
cells. Changes in surface water area are then computed. 
Runoff into the lakes is detected by the same classifier 
and it demonstrates how the crest of a flood could possibly 
be tracked on the major rivers over the world. 
DISCUSSION 
An Index using NOAA-7 satellite data is used to map the 
flooded areas in North Texas during the Fall of 1981. 
Comparisons are also made with July 1981 and June 1982. 
July 81 being a near normal year and June 1982 was another 
period of floodings. 
NOAA-n series meteorological satellites are polar orbiting 
and pass over every location of the earth at least twice 
each day. Advanced Very High Resolution (AVHRR) data is 
collected for four channels and when engineered so, for 
five channels. These channels are: