Table 52 (continued) 225 



GEOPOTENTIAL COMPUTATIONS 



2. Determine the mean adjusted virtual temperature t'mv ( C C.) : 



(a) between the surface level and the first standard pressure surface above it, 



(b) between each successive pair of standard pressure surfaces, and 



(c) between the highest point reached and the nearest standard pressure surface 



below it. 



3. Determine A# between the surface and the first standard pressure surface above 



it from Table 52 A. Determine A^o-^" from Table 52 D as a function of t' mv 



t'm 



and A<£ . If t'mv > 0°C. add the value of A$ -~- to A# to determine A<£ for 



Jo 



the layer, if t' m » < 0°C. the value is to be subtracted. (Note that Table 52 D 



t' 

 is given in an abbreviated form. Since the function A$ -~- is linear in both 



To 

 A<i>o and t'mv it can be readily obtained from the table for intermediate values of 



A# ; e.g., if A$„= 1260 gpm. add together the values of A<t> lf^ f or A$ = 1000 



T o 

 gpm., 200 gpm., and 60 gpm. as determined from the table for the appropriate 



* mV'J 



4. Determine A<£ for the layers between each successive pair of standard pressure 



surfaces for the appropriate t'mv from Table 52 B. 



5. Determine A<£ between the highest point reached and the nearest standard pres- 



sure surface below it from Table 52 C. Determine A<t> -~ from Table 52 D and 



To 

 obtain A* for the layer as indicated by equation (5) (see step 3). 



6. The geopotential at any level is the sum of the geopotential differences determined 



for all the layers between sea level and the level in question. 



Table 51 gives the relationship between geopotential and heights measured in geometric 

 units. 



(continued) 



SMITHSONIAN METEOROLOGICAL TABLES 



