bccal: Calibrate Bristow-Campbell model

In sirad: Functions for Calculating Daily Solar Radiation and Evapotranspiration

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.

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

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)

Example output

  BCb_nls 
0.1052263 

sirad documentation built on May 1, 2019, 7:42 p.m.