Conventional surface ship data concurrent with the selected cases -were re- 

 quested from the National Weather Records Center (NWRC), but unfortunately not 

 a single ship had filed reports for the desired areas during the appropriate time 

 period. 



There are several interesting features in the temperature pattern presented 

 in Figure 5-1. There is a strong indication of the cold Labrador Current, which 

 moves south'ward off the eastern coast of Labrador. To the east of the current 

 there is a nearly isothermal region, probably due to mixing with a warm counter - 

 current which moves northward along the western coast of Greenland. There is 



some indication of this warm current in the extreme eastern edge of the analysis, 

 but the significance of the pattern there is speculative. 



A pass on the previous day was found to be largely cloud covered (based on 

 a Channel 5 10 % albedo threshold), but a small clear area of the earlier pass did 

 overlap a restricted area in the southwest corner of Pass 1126. This was Pass 1111 

 of TIROS VII, on 2 September 1963 at 1213Z. The limited SST data from Pass 1111 

 seemed to fit well with those from Pass 1126 and are included in Figure 5-1. 



Figure 5-2 shows the analysis of a still earlier pass over this same area. 

 These data are taken from Pass 1082 of TIROS VII, on 31 August 1963 at approximately 

 1309Z. The useful SST data were somewhat more restricted by cloudiness in this 

 case, and seemed in general more noisy. When compared with Figure 5--1, Figure 5-2 

 shows that the detailed structure is considerably changed, but the gross pattern 

 remains the same. Whether or not actual synoptic changes are shown by the difference 

 in detailed structure could not be determined because of the apparent noise in the 

 IR data and the lack of conventional data. There is still an indication of the Labrador 

 current off the east coast of Labrador, with a generally isothermal area east of the 

 current. 



The uncorrected Channel 2 values shown in Figure 5-2 average about 2. 5 K 

 higher than those for Pass 1126. Because of a decrease in the moisture content of 

 the upper atmosphere, the attenuation correction in this case is only 5 K (1 K less 

 than for Pass 1126) while the correction for sensor degradation remained at 2 K. 

 After these corrections, the approximate average temperature of the field of view in 

 Pass 1082 is 274. 5°K, or 1. 5°K higher than that seen in Passes 1111 and 1126. 



There are indications that such an average temperature change over an area of this 



17 

 size is quite reasonable , but, without conventional data, the reality of this change 



could not be substantiated. 



19 



