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Evaporative Capacity of Unsaturated Air
Author(s) -
Showalter A. K.
Publication year - 1971
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr007i003p00688
Subject(s) - wet bulb temperature , evaporative cooler , psychrometrics , environmental science , humidity , relative humidity , air temperature , atmospheric sciences , hydrology (agriculture) , dry bulb temperature , meteorology , physics , geotechnical engineering , geology
Falling water droplets quickly assume surface temperatures equal to the wet‐bulb temperature of the air. Formulas for absolute humidity and Ferrel's psychrometric formula are used to develop a simple relationship for calculating the capacity of air to absorb water droplets evaporated into it. Such data are relevant for determining water losses during sprinkler irrigation, the discrepancy between radar observed liquid water contents and ground observed rainfall and other factors important in the hydrologic balance of the atmosphere. The evaporative capacity E 0 in g/m 3 of the air is determined to be explicitly defined by an equation involving wet‐bulb temperature T w in °K, wet‐bulb depression Δ t w in °C, and atmospheric pressure ρ in mb E 0 = (p·Δ t w )/(7 T w )