Description Usage Arguments Details Value Author(s) References See Also Examples
Function estimates Hargreaves model coefficients 'A' and 'B' based on reference data
1 |
lat |
Latitude in decimal degrees. |
days |
Vector of class 'Date' of length n. |
rad_mea |
Vector of length n containing reference (e.g. measured) solar radiation [MJm-2]. |
extraT |
Optional. Vector of length n of extraterrestrial solar radiation [MJm-2]. If 'NULL' then it is calculated by the function. Providing extraterrestrial solar radiation speeds up the computation |
tmax |
Vector of length n containing daily maximum temperature [C]. |
tmin |
Vector of length n containing daily minumum temperature [C]. |
Function estimates Hargreaves model coefficients 'A' and 'B' based on reference (e.g. measured) solar radiation data. It performs a linear regression.
Vector of length 3 containing:
Ha |
Hargreaves 'A' coefficient |
Hb |
Hargreaves 'B' coefficient |
Hr2 |
Coefficient of determination of performed linear regression |
Jedrzej S. Bojanowski
Hargreaves, G.H., Samini, Z.A. 1892. Estimating potential evapotranspiration. J. Irrig. Darin. Eng., ASCE 108 (3), 225-230.
'ha'
1 2 3 4 5 6 7 |
Ha Hb Hr2
0.1732065 -0.1358756 0.8446852
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