dayrange: This function determines the diurnal range.

Description Usage Arguments Value See Also Examples

View source: R/dayrange.R

Description

The function calculates the difference of maximum and minimum values of hourly data from a single CM SAF NetCDF input file.

Usage

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dayrange(var, infile, outfile, nc34 = 4, overwrite = FALSE, verbose = FALSE)

Arguments

var

Name of NetCDF variable (character).

infile

Filename of input NetCDF file. This may include the directory (character).

outfile

Filename of output NetCDF file. This may include the directory (character).

nc34

NetCDF version of output file. If nc34 = 3 the output file will be in NetCDFv3 format (numeric). Default output is NetCDFv4.

overwrite

logical; should existing output file be overwritten?

verbose

logical; if TRUE, progress messages are shown

Value

A NetCDF file including a time series of the diurnal range is written (character).

See Also

Other daily statistics: dayavg(), daymax(), daymean(), daymin(), daypctl(), daysd(), daysum(), dayvar(), ydaymax(), ydaymean(), ydaymin(), ydayrange(), ydaysd(), ydaysum()

Examples

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## Create an example NetCDF file with a similar structure as used by CM
## SAF. The file is created with the ncdf4 package.  Alternatively
## example data can be freely downloaded here: <https://wui.cmsaf.eu/>

library(ncdf4)

## create some (non-realistic) example data

lon <- seq(5, 15, 0.5)
lat <- seq(45, 55, 0.5)
time <- seq(ISOdate(2000, 1, 1), ISOdate(2000, 1, 6), "hours")
origin <- as.Date("1983-01-01 00:00:00")
time <- as.numeric(difftime(time, origin, units = "hour"))
data <- array(250:350, dim = c(21, 21, 121))

## create example NetCDF

x <- ncdim_def(name = "lon", units = "degrees_east", vals = lon)
y <- ncdim_def(name = "lat", units = "degrees_north", vals = lat)
t <- ncdim_def(name = "time", units = "hours since 1983-01-01 00:00:00",
 vals = time, unlim = TRUE)
var1 <- ncvar_def("SIS", "W m-2", list(x, y, t), -1, prec = "short")
vars <- list(var1)
ncnew <- nc_create(file.path(tempdir(),"CMSAF_example_file.nc"), vars)
ncvar_put(ncnew, var1, data)
ncatt_put(ncnew, "lon", "standard_name", "longitude", prec = "text")
ncatt_put(ncnew, "lat", "standard_name", "latitude", prec = "text")
nc_close(ncnew)

## Determine the diurnal range of the example CM SAF NetCDF file and
## write the output to a new file.
dayrange(var = "SIS", infile = file.path(tempdir(),"CMSAF_example_file.nc"), 
 outfile = file.path(tempdir(),"CMSAF_example_file_dayrange.nc"))

unlink(c(file.path(tempdir(),"CMSAF_example_file.nc"), 
 file.path(tempdir(),"CMSAF_example_file_dayrange.nc")))

cmsafops documentation built on Sept. 6, 2021, 9:09 a.m.

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