su: Supit-Van Kappel solar radiation model

In sirad: Functions for Calculating Daily Solar Radiation and Evapotranspiration

Description

'su()' calculates daily solar radiation based on daily cloud coverage and temperature range using Supit-Van Kappel model.

Usage

su(days, lat, lon, extraT=NULL, A=NA, B=NA, C=NA, tmax, tmin, CC)

Arguments

days	Vector of class 'Date' of length n.
lat	Latitude in decimal degrees.
lon	Longitude in decimal degrees.
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
A	Supit-Van Kappel model coefficient 'A'. If 'NA' then A is derived from the map of interpolated coefficients estimated from Meteosat solar radiation data. See details.
B	Supit-Van Kappel model coefficient 'B'. If 'NA' then B is derived from the map of interpolated coefficients estimated from Meteosat solar radiation data. See details.
C	Supit-Van Kappel model coefficient 'C'. If 'NA' then C is derived from the map of interpolated coefficients estimated from Meteosat solar radiation data. See details.
tmax	Vector of length n containing daily maximum temperature [C].
tmin	Vector of length n containing daily minumum temperature [C].
CC	Vector of length n containing daily cloud coverage [octas].

Details

Supit and Van Kappel proposed a method for estimating solar radiation from daily cloud coverage and temperature range. Model coefficients A, B and C (if not provided) are derived from interpolated Meteosat-based coefficients from Bojanowski et al. 2013.

Value

Vector of length n of daily solar radiation [MJm-2].

Note

'CC', 'Tmax', 'Tmin' can contain NA's, but length of vectors 'CC', 'Tmax', 'Tmin' and 'days' has to be the identical.

Author(s)

Jedrzej S. Bojanowski

References

Bojanowski, J.S., Vrieling, A., Skidmore, A.K., 2013. Calibration of solar radiation models for Europe using Meteosat Second Generation and weather station data. Agricultural and Forest Meteorology 176:1-9.
Supit, I. 1994. Global radiation. Publication EUR 15745 EN of the Office for Official Publications of the EU, Luxembourg.
Supit, I., Kappel, R.R. van, 1998. A simple method to estimate global radiation. Solar Energy, 63:147-160.

See Also

'sucal' to calibrate the model.

Examples

require(zoo)
data(Metdata)
tmax <- Metdata$meteo$TEMP_MAX
tmin <- Metdata$meteo$TEMP_MIN
cc <- Metdata$meteo$CLOUD_DAYTIME_TOTAL
days <- Metdata$meteo$DAY
lat <- Metdata$LATITUDE
lon <- Metdata$LONGITUDE
plot(zoo(su(days=days, lat=lat, lon=lon, extraT=NULL, A=NA, B=NA, 
C=-NA, tmax=tmax, tmin=tmin, CC=cc),order.by=days))

Example output

Loading required package: zoo

Attaching package: ‘zoo’

The following objects are masked from ‘package:base’:

    as.Date, as.Date.numeric

sirad documentation built on May 2, 2019, 4:41 p.m.