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Evaporation and evapotranspiration in southern nigeria
Author(s) -
Chapas L. C.,
Rees A. R.
Publication year - 1964
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49709038510
Subject(s) - evapotranspiration , lysimeter , pan evaporation , environmental science , evaporation , potential evaporation , hydrology (agriculture) , meteorology , geography , soil water , soil science , geology , ecology , geotechnical engineering , biology
Data are presented on a 4‐weekly basis over the two years 1961 and 1962 for evaporation from three types of evaporation pan, and an evaporation estimate by Penman's method. Evapotranspiration was estimated by the methods of Penman, Blaney‐Criddle, Thornthwaite, and Garnier's modification of Thornthwaite's method. Grass covered lysimeters receiving only rainfall gave actual evapotranspiration, or were watered daily to give potential evapotranspiration. Actual evapotranspiration measurements are compared with theoretical estimates. Potential evapotranspiration is overestimated by Thornthwaite's method and slightly underestimated by that of Penman. the true value is about 120 cm annually with a marked seasonal variation which follows the bi‐modal radiation cycle. Actual evapotranspiration is 50 cm less than this, marked departure from the potential rate occurring during the main and subsidiary dry seasons.