50 55 60 65 



TEMPERATURE (° F) 

 50 55 60 65 70 



50 55 60 



FIGURE 10 TYPICAL EXAMPLE OF LARGE POSITIVE SURFACE TEMPERATURE ANOMALY 

 DUE TO HEATING 



Data from all of the Atlantic stations show that 8k percent of 

 surface and 400-foot anomalies generally have the sarae sign. The remainder 

 are of different sign and may be considered to be uncorrelated or of 

 different origins. However, an eq.ual amount of the anomalies of the same 

 sign at both levels may also be considered uncorrelated; that is, they 

 may be of different origins. Uncorrelated anomalies of the same sign may 

 be detected by examining the data for large differences in magnitude of 

 anomalies at the two levels. Such detection is difficult owing to un- 

 satisfactory establishment of an objective criterion for a large difference 

 of anomalies at the two levels. The only available basis for such a 

 criterion is the annual distribution of 400-foot and surface anomaly 

 ratios. Figure 8 shows that the maximum annual range of the ratios 

 (0.55) equals it2 percent of the maximum annual value of the ratio (1.3). 

 By adding 0.5°F, the likely error between temperature measurements at 

 two levels (table 1, reference 5), we obtain significance limits of 



± I = 0.42 A9 + 0.5 (13) 



where A6 is the larger value in a pair of anomalies. If the significance 

 limits are exceeded, the difference of ratios is considered large. For 

 example, if the surface anomaly is the larger of a pair and is equal to 

 3.0°F, the significance limits are ± 1.76°F (equation I3), resulting in 

 limits of 1.24° and k.^6°F (3.0°F± I.76) . Any 400-foot anomaly between 

 these limits would be considered correlated; an anomaly beyond these 

 limits would be considered uncorrelated. Of 201 pairs, 2k pairs are 

 uncorrelated anomalies with the same sign, so that 12 percent were assvuued 

 to be line or related. This percentage closely approximates the 16 percent 

 of uncorrelated anomalies of different signs. Some of the uncorrelated 

 anomalies with coinciding signs (probably 2 to 4 percent) may have smaller 



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