There was no useful IR pass over the area on the 24th of June, but, on the 

 2 5th, TIROS Pass 95 again encountered clear skies over the Sea of Okhotsk. By 

 this time, minimum nadir angles -were near or above 45 . As a result, the validity 

 of the analysis of this day is questionable, although, as may be seen in Figure 5-6, 

 the fundamental large scale features remained intact. The warm waters in the 

 northeastern part of the Sea of Okhotsk, seen in Pass 51, have not reappeared. Upper 

 air data, again from Alexandrovsk, indicated a net increase in moisture on this day 

 of such an extent that, under similar geometric conditions, the IR recorded temperature 

 would be expected to be from 1/2 to 1 degree lower. 



5. 3. 2 Gulf of Alaska Case 



The second area selected in the series of consistency tests was the Gulf of 

 Alaska, just southeast of the Alaskan Peninsula. This area appears on mean 

 monthly maps as a large, nearly isothermal region with an average August tem- 

 perature of about 284 K. Unfortunately there was only a restricted area of cloud 



free (as determined by relative changes in the Channel 5 data) overlap between the 

 two passes available, and that in an isothermal region devoid of pattern. The data 

 as analyzed in Figure 5-7 were largely taken from Pass 735 of TIROS VII on 8 August 

 1963 at 0324Z. The dashed line in the southeast corner of the figure represents 

 the northern extent of the overlapping data from Pass 748 on the following day at 

 0024Z . Pass 748 also showed this region to be isothermal, and at the same absolute 

 temperature as indicated by Pass 735. 



Upper air data for both days from the Alaskan King Salmon station indicated 

 a well mixed lower layer with near saturation from the surface to about 800 mb. 

 Because of the relatively cold air temperatures, however, this did not represent 

 a significant amount of precipitable water, and the correction term is only 5 K. 

 Combined with a 2 correction for sensor degradation, the average corrected IR 

 temperature becomes about 280 K. Again, the corrected temperatures are some- 

 what less than the true values. 



In spite of its limited applicability as a consistency test, this case is considered 

 worthwhile because of the suggestion of a warm current moving westward at about 

 58 N (see Fig. 5-7), which is not analyzed in mean monthly charts. At about 42 N, 

 the North Pacific Current moves due east across the Pacific Ocean toward the 

 American mainland. (It is originally formed to the east of the Asian continent 



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