APPENDIX 



133 



dry adiabatic lapse rate (5.5 ¥ per 1,000 ft or 1 (J 

 per 100 m) . There must be no coudeiisatioii or evapora- 

 tion of associated water vajjor during the process. 



Suh-sidence. An extensive sinking process, result- 

 ing in dynamically heated air and an increase in 

 stability, most frequently observed in anticyclones, is 

 known as subsidence. 



Instbuctions foe Use of Nomogkam 



This nomogram (Figure 23) may be used to com- 

 pute M when temperature is expressed in degrees 

 Fahreidieit or centigrade, humidity in terms of wet 



liull) (degrees Falirenheit or degrees centigrade), dew 

 poijit (degrees centigrade), or vapor pressure (milli- 

 bars), and height in feet or meters. Place a straight- 

 edge so as to align the temperature on scale 1 with the 

 wet bulb temperature on scale 3 (or with the dew point 

 or vapor pressure on scale 4). The point at •\\'1iich the 

 straightedge intersects scale 6 indicates the value 

 of the modified index uncorrected for height. Pivot 

 the straightedge at this point (on scale 6) so that 

 it crosses scale 3 at the desired height. Then read the 

 value of M where the straightedge crosses scale 5. 



