20c 



DYNAMIC METEOROLOGY AND HYDROGRAPHY. 



Table 17 A. Temperature correction to be added to the virtual temperature at the earth's surface 

 in order to give the most probable average virtual temperatures in the sheet between the 

 earth's surface and the nearest standard isobaric surfaces [based upon statistics). 



Extrapolation below the earth's surface (common for all pressures and seasons). 



Temper- 

 ature 

 correc- 

 tion 



( F.). 



4-5 

 5-0 

 5-4 



Example: Low pressure, spring; at station pressure 2S.S7 inches of mercury ; virtual temperature -f 50. 1 F. 



Column I. Standard surfaces. 



2. Approximate height of these surfaces, found from table 15 A for the pressure of 2S.S7 inches of mercury 



at the station. 



3. Temperature corrections according to table 17 A for low pressure spring and for the heights of column 2. 



4. Most probable average virtual temperature of the sheets between the earth and the standard surfaces of 



column 1, found bv addition of the corrections of column 3 to the virtual temperature at the station 

 + 50.1 F. 



5. Corrections to the height of column 2, found from table 16 a for the heights of column 2 and the average 



virtual temperature of column 4. 



6. Height of the standard surfaces above the station found by addition of the approximate heights of 



column 1 and the corrections of column 5. 



