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Effect of atmospheric stability on water temperature predictions for a thermally loaded stream
Author(s) -
DeWalle David R.
Publication year - 1976
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/wr012i002p00239
Subject(s) - atmospheric instability , evaporation , stability (learning theory) , environmental science , wind speed , convection , mechanics , atmospheric sciences , thermodynamics , meteorology , materials science , physics , machine learning , computer science
A steady state one‐dimensional energy budget equation was numerically integrated to predict water temperatures in a 5.45‐km‐long thermally loaded stream reach for 131 five‐ or six‐hour periods. Downstream water temperature prediction errors (measured minus predicted) using Jobson's Lake Hefner evaporation equation averaged −2.11°C and were well correlated ( R 2 = 46%) with an index to atmospheric stability. Use of a modified form of Shulyakovskiy's evaporation equation, which includes a term for evaporation by free convection, significantly reduced the average prediction error to 0.89°C and eliminated the effects of atmospheric stability ( R 2 < 1%). Correction of wind velocity data for the velocity of the air relative to the stream velocity also reduced prediction errors.