calcG0: Irradiation and irradiance on the horizontal plane.
In solaR: Radiation and Photovoltaic Systems

Description Usage Arguments Value Author(s) References See Also Examples

This function obtains the global, diffuse and direct irradiation and irradiance on the horizontal plane from the values of daily and intradaily global irradiation on the horizontal plane. It makes use of the functions calcSol, fCompD, fCompI, fBTd and readBD (or equivalent).

Besides, if information about maximum and minimum temperatures values are available it obtains a series of temperature values with fTemp.

calcG0(lat, modeRad = 'prom', dataRad,
       sample = 'hour', keep.night = TRUE,
       sunGeometry = 'michalsky',
       corr, f, ...)

`lat`	numeric, latitude (degrees) of the point of the Earth where calculations are needed. It is positive for locations above the Equator.
`modeRad`	A character string, describes the kind of source data of the global irradiation and ambient temperature. It can be `modeRad = 'prom'` for monthly mean calculations. With this option, a set of 12 values inside `dataRad` must be provided, as defined in `readG0dm`. `modeRad = 'aguiar'` uses a set of 12 monthly average values (provided with `dataRad`) and produces a synthetic daily irradiation time series following the procedure by Aguiar etal. (see reference below). If `modeRad = 'bd'` the information of daily irradiation is read from a file, a `data.frame` defined by `dataRad`, a `zoo` or a `Meteo` object. (See `readBD`, `df2Meteo` and `zoo2Meteo` for details). If `modeRad = 'bdI'` the information of intradaily irradiation is read from a file, a `data.frame` defined by `dataRad`, a `zoo` or a `Meteo` object. (See `readBDi`, `dfI2Meteo` and `zoo2Meteo` for details).
`dataRad`	If `modeRad = 'prom'` or `modeRad = 'aguiar'`, a numeric with 12 values or a named list whose components will be processed with `readG0dm`. If `modeRad = 'bd'` a character (name of the file to be read with `readBD`), a `data.frame` (to be processed with `df2Meteo`), a `zoo` (to be processed with `zoo2Meteo`), a `Meteo` object, or a `list` as defined by `readBD`, `df2Meteo` or `zoo2Meteo`. The resulting object will include a column named `Ta`, with information about ambient temperature. If `modeRad = 'bdI'` a character (name of the file to be read with `readBDi`), a `data.frame` (to be processed with `dfI2Meteo`), a `zoo` (to be processed with `zoo2Meteo`), a `Meteo` object, or a `list` as defined by `readBDi`, `dfI2Meteo` or `zoo2Meteo`. The resulting object will include a column named `Ta`, with information about ambient temperature.
`sample`	`character`, containing one of ‘"sec"’, ‘"min"’, ‘"hour"’. This can optionally be preceded by a (positive or negative) integer and a space, or followed by ‘"s"’ (used by `seq.POSIXt`). It is not used when `modeRad = "bdI"`.
`keep.night`	`logical`. When it is TRUE (default) the time series includes the night.
`sunGeometry`	`character`, method for the sun geometry calculations. See `calcSol`, `fSolD` and `fSolI`.
`corr`	A character, the correlation between the the fraction of diffuse irradiation and the clearness index to be used. With this version several options are available, as described in `corrFdKt`. For example, the `FdKtPage` is selected with `corr = 'Page'` while the `FdKtCPR` with `corr = 'CPR'`. If `corr = 'user'` the use of a correlation defined by a function `f` is possible. If `corr = 'none'` the object defined by `dataRad` should include information about global, diffuse and direct daily irradiation with columns named `G0d`, `D0d` and `B0d`, respectively (or `G0`, `D0` and `B0` if `modeRad = 'bdI'`). If `corr` is missing, then it is internally set to `CPR` when `modeRad = 'bd'`, to `Page` when `modeRad = 'prom'` and to `BRL` when `modeRad = 'bdI'`.
`f`	A function defininig a correlation between the fraction of diffuse irradiation and the clearness index. It is only neccessary when `corr = 'user'`
`...`	Additional arguments for `fCompD` or `fCompI`

A G0 object.

Oscar Perpiñán Lamigueiro.

Perpiñán, O, Energía Solar Fotovoltaica, 2015. (https://oscarperpinan.github.io/esf/)
Perpiñán, O. (2012), "solaR: Solar Radiation and Photovoltaic Systems with R", Journal of Statistical Software, 50(9), 1-32, doi: 10.18637/jss.v050.i09
Aguiar, Collares-Pereira and Conde, "Simple procedure for generating sequences of daily radiation values using a library of Markov transition matrices", Solar Energy, Volume 40, Issue 3, 1988, Pages 269–279

calcSol, fCompD, fCompI, readG0dm, readBD, readBDi, corrFdKt.

G0dm = c(2.766, 3.491, 4.494, 5.912, 6.989, 7.742, 7.919, 7.027, 5.369, 3.562, 2.814, 2.179)*1000;
Ta = c(10, 14.1, 15.6, 17.2, 19.3, 21.2, 28.4, 29.9, 24.3, 18.2, 17.2, 
  15.2)

g0 <- calcG0(lat = 37.2, modeRad = 'prom', dataRad = list(G0dm = G0dm, Ta = Ta))
print(g0)
xyplot(g0)

## Aguiar et al.

g0 <- calcG0(lat = 37.2, modeRad = 'aguiar', dataRad = G0dm)
print(g0)
xyplot(g0)

##Now the G0I component of g0 is used as
##the bdI argument to calcG0 in order to
##test the intradaily correlations of fd-kt

BDi = as.zooI(g0)
BDi$Ta = 25 ##Information about temperature must be contained in BDi

g02 <- calcG0(lat = 37.2, 
            modeRad = 'bdI', 
            dataRad = list(lat = 37.2, file = BDi), 
            corr = 'none')

print(g02)

g03 <- calcG0(lat = 37.2, 
            modeRad = 'bdI', 
            dataRad = list(lat = 37.2, file = BDi), 
            corr = 'BRL')
print(g03)

xyplot(fd ~ kt, data = g03, pch = 19, alpha = 0.3)

## Not run: 
##NREL-MIDC
##La Ola, Lanai
##Latitude: 20.76685o North
##Longitude: 156.92291o West
##Elevation: 381 meters AMSL
##Time Zone: -10.0

NRELurl <- 'http://goo.gl/fFEBN'

dat <- read.table(NRELurl, header = TRUE, sep = ',')
names(dat) <- c('date', 'hour', 'G0', 'B', 'D0', 'Ta')

##B is direct normal. We need direct horizontal.
dat$B0 <- dat$G0 - dat$D0

##http://www.nrel.gov/midc/la_ola_lanai/instruments.html:
##The datalogger program runs using Greenwich Mean Time (GMT), 
##data is converted to Hawaiin Standard Time (HST) after data collection
idxLocal <- with(dat, as.POSIXct(paste(date, hour), format = '%m/%d/%Y %H:%M', tz = 'HST'))
idx <- local2Solar(idxLocal, lon = -156.9339)

NRELMeteo <- zoo(dat[, c('G0', 'D0', 'B0', 'Ta')], idx)

lat = 20.77

g0 <- calcG0(lat = lat, modeRad = 'bdI', dataRad = NRELMeteo, corr = 'none')
xyplot(g0)
xyplot(as.zooI(g0), superpose = TRUE)

g02 <- calcG0(lat = lat, modeRad = 'bdI', dataRad = NRELMeteo, corr = 'BRL')
xyplot(g02)
xyplot(as.zooI(g02), superpose = TRUE)
xyplot(fd ~ kt, data = g02, pch = 19, cex = 0.5, alpha = 0.5)

g03 <- calcG0(lat = lat, modeRad = 'bdI', dataRad = NRELMeteo, corr = 'CLIMEDh')
xyplot(g03)
xyplot(as.zooI(g03), superpose = TRUE)
xyplot(fd ~ kt, data = g03, pch = 19, cex = 0.5, alpha = 0.5)

## End(Not run)