calc_solar_insolation: Model solar insolation on a horizontal surface (W/m2 ==...

In USGS-R/streamMetabolizer: Models for Estimating Aquatic Photosynthesis and Respiration

Model solar insolation on a horizontal surface (W/m2 == J/s/m2) as in http://education.gsfc.nasa.gov/experimental/July61999siteupdate/inv99Project.Site/Pages/solar.insolation.html

Description

Model solar insolation on a horizontal surface (W/m2 == J/s/m2) as in http://education.gsfc.nasa.gov/experimental/July61999siteupdate/inv99Project.Site/Pages/solar.insolation.html

Usage

calc_solar_insolation(
  app.solar.time,
  latitude,
  max.insolation = convert_PAR_to_SW(2326),
  format = c("degrees", "radians"),
  attach.units = deprecated()
)

Arguments

app.solar.time	POSIXct vector of date-time values in apparent solar time, e.g., as returned by convert_UTC_to_solartime(..., time.type="apparent solar")
latitude	numeric value or vector indicating the site latitude in decimal degrees (never radians or deg-min-sec, no matter what format is) between -90 (South Pole) and 90 (North Pole).
max.insolation	insolation rate at solar noon, W/m2 == J/s/m2. varies greatly with atmospheric conditions
format	The format of both the input and the output. May be "degrees" or "radians".
attach.units	(deprecated, effectively FALSE in future) logical. Should the returned vector be a unitted object?

Examples

insdf <- data.frame(
  lat=rep(c(0,20,40,60), each=48*4),
  date=rep(as.Date(sprintf('2004-%d-15', rep(c(1,4,7,10), each=48)), tz='UTC'), times=4),
  hour=rep(seq(0,23.5,0.5), times=4*4)
)
insdf <- transform(insdf, datetime=lubridate::with_tz(as.POSIXct(date), 'UTC') +
  as.difftime(hour, units='hours'))
insdf <- transform(insdf, date=as.character(date))
insdf <- transform(insdf, ins=calc_solar_insolation(datetime, lat))
## Not run: 
library(ggplot2)
ggplot(insdf, aes(color=date, y=ins, x=hour)) +
  geom_line() + facet_wrap(~lat) +
  ggtitle('solar insolation by latitude (panels) and day of year (colors)')

## End(Not run)

USGS-R/streamMetabolizer documentation built on Aug. 15, 2023, 7:50 a.m.