pattern consistency revealed in these tests, it is felt that even a single pass over a 

 given area can usually provide an accurate indication of at least the large scale SST 

 gradient patterns. If a conventional measurement is available for a benchmark, 

 reasonably accurate absolute values of SST can be deduced. 



5.4 Real-Time Studies 



As discussed in Section 3.2. 3, the greatest density of conventional ship SST 

 reports occurs off the eastern coast of the United States. It is here also that the 

 most investigated of the ocean's major currents, the Gulf Stream, provides an 

 excellent opportunity to observe synoptic scale temperature changes, especially 

 along its edges. Unfortunately, there is very little regularly processed TIROS IR 

 data for this region; most of the IR data for this area are the so-called "real-timei' 

 data, which currently require a special, long and laborious conversion to usable 

 form. 



For these reasons, only three "real-time" cases for this area were selected 

 and ordered from the Computations Group at NASA's Goddard Space Flight Center. 

 Of these three cases, timing errors caused the rejection of one of them, and were 

 prevalent in a second. The remaining case proved to be satisfactory, although 

 noiser than the usual IR data. The analysis of the first of these cases is presented 

 in Figure 5-11. These data are from Direct Pass 107 of TIROS VII, on 26 June 1963. 

 This is the better of the two usable "real-time" cases, and clearly shows evidence 

 of both the southbound Labrador Current and the Gulf Stream. These patterns show 



considerable similarity to the most recent mean monthly charts available for this 



22 

 area. The dashed isotherms in Figure 5-11 represent best estimates, used to 



bridge areas of poor data. 



Upper air data from Washington, D. C. for this date revealed a low relative 



humidity throughout the atmosphere, except very near the surface. Recorded air 



temperatures were relatively high. Atmospheric attenuation calculations indicated 



that an approximate 5 K temperature correction should be added to the recorded 



Channel 2 values. This pass occurred rather early in the lifetime of TIROS VII, and 



no sensor degradation correction is required. With these corrections, the recorded 



temperatures are about 12 K lower than those indicated for this region in mean 



monthly charts. 



37 



