Description Usage Arguments Details Value Author(s) References See Also Examples
Function estimates Angstrom-Prescott 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 |
DL |
Optional. Vector of length n of day length [h]. If 'NULL' then it is calculated by the function. Providing day length speeds up the computation |
SSD |
Vector of length n containing sunshine duration [in hours]. |
Function estimates Angstrom-Prescott model coefficients 'A' and 'B' based on reference (e.g. measured) solar radiation data. It performs a linear regression in which 'rad_mea' is dependent variable and a proporsion of 'SSD' and astronomical day length is an independent variable.
Vector containing:
APa |
Angstom-Prescott 'A' coefficient |
APb |
Angstom-Prescott 'B' coefficient |
APr2 |
Coefficient of determination of performed linear regression |
Jedrzej S. Bojanowski
Angstrom, A., 1924. Solar and terrestrial radiation. Quarterly Journal of the Royal Meteorological Society, 50:121-125.
Prescott, J.A., 1940. Evaporation from a water surface in relation to solar radiation. Transactions of the Royal Society of South Australia, 64:114-118.
'ap' to use Angstrom-Prescott model
1 2 3 4 5 6 7 |
APa APb APr2
0.2089758 0.5609707 0.8755487
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