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daypctl

Determine daily percentiles


Description

The function determines daily percentiles from data of a single CM SAF NetCDF input file.

Usage

daypctl(
  var,
  p = 0.95,
  infile,
  outfile,
  nc34 = 4,
  overwrite = FALSE,
  verbose = FALSE
)

Arguments

var

Name of NetCDF variable (character).

p

Percentile number given as probability within [0, 1] (numeric). Default is 0.95.

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 daily percentiles is written.

See Also

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

Examples

## 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 90% daily percentiles of the example CM SAF NetCDF file and
## write the output to a new file.
daypctl(var = "SIS", p = 0.9, infile = file.path(tempdir(),"CMSAF_example_file.nc"), 
 outfile = file.path(tempdir(),"CMSAF_example_file_daypctl.nc"))

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

cmsafops

Tools for CM SAF NetCDF Data

v1.1.1
GPL (>= 3)
Authors
Steffen Kothe [aut, cre]
Initial release

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