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Daily and seasonal changes in the surface temperature of fallow soil at rothamsted
Author(s) -
Penman H. L.,
Keen B. A.
Publication year - 1943
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.49706929802
Subject(s) - air temperature , evaporation , environmental science , atmospheric sciences , surface air temperature , diurnal temperature variation , maximum temperature , maxima , meteorology , precipitation , geology , physics , art , performance art , art history
A method of obtaining continuous records are discussed. The relations between surface and sub‐surface temperatures are briefly considered, and then, in more detail, the inter‐dependence of soil surface and air temperatures is examined. At all seasons the soil temperature is in phase with solar radiation whereas the maximum air temperature is delayed; for air maxima below 52° F. the daily range of soil surface temperature is approximately the same as that of the air temperature. Above this threshold the soil surface maximum increases twice as rapidly as the air maximum. Using this value of the air maximum, 5244F., to divide the year into two seasons, it is found that the winter and summer periods so separated are the same as those previously obtained form the criterion:—Seasonal evaporation is equal to or less than that from an open water surface. Interest is primarily centred on the summer season, in which the soil surface temperature exceeds that of the air for a considerable part of the day, and for a rainless summer period of t days an anticipated relation of the form ΣE=at1/n, where n=3, a is a constant and ΣE=the total evaporation, is confirmed from the Rothamsted records. The effect of the diurnal oscillation of surface temperature on germinating seed is briefly discussed.