CORRELATION OF WIND FLOW AND TEMPERATURE 



WITH EVAPORATION 1 



CHARLES A. SHULL 



University of Kentucky, Lexington, Kentucky 



Several years ago the United States Department of Agricul- 

 ture inaugurated the study of evaporation rates under standard- 

 ized conditions on an extensive scale. While a few stations 

 existed prior to 1916, that year saw the establishment of what 

 are known as Standard Class A Evaporation Stations across the 

 continent from east to west, especially in the more arid western 

 half of the country. On January 1, 1918, there were thirty of 

 these stations on the continental United States, and one at San 

 Juan, Porto Rico. 



The stations are standardized as to exposure, size of pan, posi- 

 tion of instruments, etc. The pan is 48 inches in diameter 10 

 inches deep, and is kept with 7 or 8 inches of water, the level of 

 which is measured accurately by a hook gage constructed to 

 read to the thousandth of an inch. The data taken include 

 maximum and minimum temperatures, precipitation, air move- 

 ment and its prevailing direction, and evaporation. 



Two of these stations were established in Kansas, one near the 

 western edge of the state at Tribune, and one at the University of 

 Kansas, Lawrence. The station at Lawrence was located on 

 top of Mount Oread, the highland at the junction of the Waka- 

 rusa and Kaw river valleys, at an altitude a little over 1000 feet. 

 The elevation is about 200 feet above the flood plain to the tiorth, 

 east, and south. The location as given in the description fur- 

 nished to the Department of Agriculture is latitude 38° 57' 35", 

 longitude 95° 14' 55". 



1 Contributions from the Botanical Laboratories of the University of Ken- 

 tucky No. 2. 



210 



