Results of the Earnscleugh Observations 



The results of analysing the temperature observations at Earnscleugh 

 are given in Tables 1, 2, and 3. Table 1 contains the mean monthly 

 maximum and mean monthly minimum soil temperatures recorded at 

 depths of 3 in. and 5 in. respectively as well as monthl}' mean values 

 •of the soil temperature for each depth as calculated from the formula 

 h (max. + min.). For purposes of comparison the same quantities are 

 also given for air temperature as measured at a height of 4 ft. abo\-e 

 the ground in a standard (non-aspirated) Stevenson screen. 



The outstanding features of these tables may be summarized as 

 follows :— 



A. At a Depth 3 in. in the Soil (Table 1) : — 



(1) In the summer months the mean maximum soil tem- 

 peratures are considerably higher than the mean maximum 

 air temperatures. For example, in January the mean maximum 

 soil temperature was 89° f., while the mean maximum air 

 temperature reached only 77° f. In the winter months the 

 mean maximum soil temperatures are rather lower than the 

 corresponding mean maximum air temperatures. Thus in 

 Jul}' mean maximum soil temperature was 35° F., while the 

 mean maximum air temperature was 42° F. 



(2) Mean maximum air temperatures and mean maximum 

 soil temperatures become equal round about April and 

 September. 



(3) Mean minimum soil temperatures are consistently 

 higher than mean minimum air temperatures, the difference 

 being greater in summer than in winter. Thus in January 

 this difference is about 10° f., while in July it reaches only 5° f. 



B. At a Depth of 5 in. in the Soil (Table 2.) : — 



(1) In midsummer there is very little difference between 

 the mean maximum soil temperatures and the mean maximum 

 air temperatures, but at other times of the year conditions 

 are similar to those at the Sin. depth in winter, in as much 

 that the mean maximum soil temperatures are lower than 



.the mean maximum air temperatures. This difference is 

 greatest in midwinter, being then about 9° f. 



(2) As was the case with the 3 in. depth, the mean minimum 

 soil temperatures at the 5 in. depth are consistently higher 

 than the mean minimum air temperatures, the difference 

 being about 13° f. in January and about 6° f. in July. 



Table 2 shows the extreme maximum and minimum soil temperatures 

 recorded at the 3 in. and 5 in. depths, together with the respective 

 maximum and minimum air temperatures for the same days as those 

 on which the extreme maximum and minimum soil temperatures at 

 these depths occurred. Where the same extreme maximum or minimum 

 soil temperature was recorded on more than one day, the average of the 

 corresponding maximum or minimum air temperatures has been taken. 

 This table is very similar to the corresponding Table 1, the main 

 differences being in the absolute magnitudes of the temperatures 

 recorded. Thus the highest soil temperature during the period at the 

 3 in. depth was 102° f. on 3rd January, 1948 (the mean maximum for 

 January is 89° f.), and at the 5 in. depth the highest value recorded 



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