cst: Estimate clear sky transmissivity

In sirad: Functions for Calculating Daily Solar Radiation and Evapotranspiration

Description

Function estimates a clear sky transmissivity based on reference data (e.g. measured)

Usage

cst(RefRad, days, lat, extraT=NULL, perce = 3, sepYear = FALSE, stat='median')

Arguments

RefRad	Vector of length n of reference solar radiation data [MJm-2]
days	Vector of class 'Date' of length n.
lat	Latitude in radians
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
perce	Percent of days to be chosen as clear days
sepYear	Logical value. If 'TRUE' percent of days given by 'perce' of every single year are taken for calculation. If 'FALSE' percent of days given by 'perce' of all years are taken for calculation
stat	Method used to estimate final value of the clear sky transmissivity from the values derived from selected clear-sky days. Default is 'median' which is more conservative, while alternative 'max' is sensitive to outliers. If 'max' is used the value of 'perce' is not important. If 'stat' is numeric then (instead of 'median' or 'max') 'quantile' is used. 'Stat' is sent as quantile's 'probs' parameter. See ?quantile for details

Value

Numeric. Clear sky transmissivity.

Author(s)

Jedrzej S. Bojanowski

See Also

cstRead

Examples

data(Metdata)
ref <- Metdata$meteo$RAD_MEA
i <- dayOfYear(Metdata$meteo$DAY)
latr <- radians(Metdata$LATITUDE)
cst(ref,i,latr) 

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