temperature setting. It is possible to maximize the contrast between land and sec 

 and among the ocean thermal features. 

 4. image Expansion - Data from each pass covers a region 1,560 nautical miles wide 

 which can be displayed at two scales, 1:15,000,000 or t:7, 500, 000. At normal 

 scale the entire pass is displayed on 9" film at the scale of 1:7,500,000. How- 

 ever, magnification of expansion of the image is possible, allowing the observer 

 to view half of the full swath of data expanded to fill the entire width of the 9" 

 film at scale of 1:7,500,000. One can expand the center, left, or right halves 

 at any image . 



The display of a sea surface temperature gradient is illustrated schematically in figure 

 13. On the ordinate, is a plot of satellite temperature and gray shade scales, with the 

 corresponding Celsius temperatures. The abscissa is distance in nautical miles from the 

 Korean coast. The trace is actual sea surface temperature data measured by a ship's hull 

 mounted thermometer 3 November, 1972. Shown at the top is the gray shade display of 

 this temperature gradient In the same manner it would show on satellite Imagery. The 

 resultant Image, a film product, is a chart (transverse mercator projection) of the sea 

 surface thermal patterns represented by 16 gray shades. (Note - the great improvement 

 for oceanographic use possible if a thermal resolution of 0.5°C were available vice the 

 1.6°C Illustrated here). 



Figure 5 is an example of these Mil and X4 data with 295°K as the base temperature. 

 The film product was used directly as a negative to produce the figures. The black areas 

 are colder than 270°K (0°C), the white areas are warmer than 295°K (25°C). The 

 representation of warm regions as lighter shades is the convention used in this work. Clouds 

 show up as black areas, and land masses show up as white during daytime passes and black 

 during nightime passes*. This convention allows rapid reproduction of thermal Imagery 

 without production of a negative . 



Specific recommendations for handling data acquisition at remote-site receivers are 

 as follows: 



1 . Produce a VHR film product (for ascending nodes) or an HR film product (descending 

 node pass) directly from the satellite and store the IR signal on tape. 



2. During rewind of tape: 



a. produce an Ml] gray scale test pattern so that the 16 gray shades and the 

 corresponding temperature intervals can be exactly identified on the HRIR 

 product. 



3. Produce the Ml] HRIR product from the tape recorded data. 



The gridded visual data and the calibrated gray-scale wedge from the test pattern can then 

 be used In interpretation of the HRIR data. 



* These infrared Images are thus tonally inverted from the original rear real-time 

 products and the conventional meteorological displays. 



