Calibrate Bristow-Campbell model

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Description

Function estimates Bristow-Campbell model coefficient 'B' based on reference data

Usage

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bccal(lat, days, rad_mea,extraT=NULL,BCc=2,Tmax, Tmin, tal)

Arguments

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

BCc

Bristow-Campbell model coefficient 'C' usually equaled to 2.

Tmax

Vector of length n containing daily maximum temperature [C].

Tmin

Vector of length n containing daily minumum temperature [C].

tal

Clear sky transmissivity.

Details

Function estimates Bristow-Campbell model coefficient 'B' based on reference (e.g. measured) solar radiation data. It performs a non-linear least squeres regression.

Value

BCb

Bristow-Campbell 'B' coefficient

Author(s)

Jedrzej S. Bojanowski

References

Bristow, K.L., and G.S. Campbell. 1984. On the relationship between incoming solar radiation and daily maximum and minimum temperature. Agriculture and Forest Meteorology, 31:159-166.

See Also

'bc', and 'bcauto' to perform auto-calibration

Examples

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data(Metdata)
tmax <- Metdata$meteo$TEMP_MAX
tmin <- Metdata$meteo$TEMP_MIN
days <- Metdata$meteo$DAY
lat <- Metdata$LATITUDE
rad_mea <- Metdata$meteo$RAD_MEA
bccal(lat,days,rad_mea,extraT=NULL,BCc=2,tmax,tmin, tal=0.76)