sirad (version 2.3-1)

bccal: Calibrate Bristow-Campbell model

Description

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

Usage

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.

Value

BCb

Bristow-Campbell 'B' coefficient

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.

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

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)