retrieve: Retrieve field data from a netcdf file.

In metno/esd: Climate analysis and empirical-statistical downscaling (ESD) package for monthly and daily data

Retrieve field data from a netcdf file.

Description

Retrieve data from a netcdf file and return a zoo field object with attributes. retrieve assumes data on a regular lon-lat grid and retrieve.rcm reads data on irregular (rotated) grid (typically output from RCMs).

Usage

retrieve(file = NULL, ...)

Arguments

file	Name of the existing netCDF file to be opened or an object of class 'ncdf4'. The full path to the netCDF file can either be included in 'ncfile' or entered as a separate input ('path').
path	Path to netcdf file
ncid	An object of class 'ncdf4'
stid	Station IDs to read with retrieve.station
loc	locations to read with retrieve.station
lon	Numeric value of longitude for the reference point (in decimal degrees East) or a vector containing the range of longitude values in the form of c(lon.min,lon.max)
lat	Numeric value of latitude for the reference point (in decimal degrees North) or a vector containing the range of latitude values in the form of c(lat.min,lat.max)
lev	Numeric value of pressure levels or a vector containing the range of pressure level values in the form of c(lev.min,lev.max)
alt	Altititude for stations to read with retrieve.station. Negative values for reading stations below the altitude. For a range use c(alt.min,alt.max)
cntr	Countries of stations to read with retrieve.station
it	Numerical or date values of time or a vector containing the range of values in the form of c(start,end). Date format should be in the form of "YYYY-MM-DD".
is	Numerical or logical values of spatial indexing for reading station data (retrieve.station).
param	Parameter or element type. There are several core parameters or elements as well as a number of additional parameters. The parameters or elements are: auto = automatic selection. precip, prcp, pr = Precipitation (mm) tas, tavg = 2m-surface temperature (in degrees Celcius) tmax, tasmax = Maximum temperature (in degrees Celcius) tmin, tasmin = Minimum temperature (in degrees Celcius)
plot	Logical value. if, TRUE provides a map.
greenwich	Logical value. If FALSE, convert longitudes to -180E/180E or centre maps on Greenwich meridian (0 deg E). In other words, when Greenwich == TRUE, the left boundary of a global field is set to Greenwich and not the dateline.
ncdf.check	Logical value. If TRUE, performs a quick check of the ncfile contents
miss2na	Logical value. If TRUE missing values are converted to "NA"
verbose	Logical value defaulting to FALSE. If FALSE, do not display comments (silent mode). If TRUE, displays extra information on progress.
onebyone	Logical value. If TRUE, retrieve.station reads one station at the time rather than reading a block of data which can be demaning if the stations are stored in widely different parts of the netCDF file.
sort	- if TRUE, sort the metadata according to location name

Value

A "zoo" "field" object with additional attributes used for further processing.

See Also

summary.ncdf4 check.ncdf4 file.class

Examples

## Not run: 
  # Download air surface temperature (tas) for the 'NorESM1-ME' model
  # output prepared for 'CMIP5 RCP4.5' and for run 'r1i1p1' from the climate
  # explorer web portal (http://climexp.knmi.nl) and store the file into the 
  # local machine, e.g. temporary folder '/tmp' (Size ~96Mb) using the following
  # command if needed. Otherwise, specify a netcdf file to retrieve data from. 
  url <- "http://climexp.knmi.nl/CMIP5/monthly/tas"
  noresm <- "tas_Amon_NorESM1-ME_rcp45_000.nc"
  download.file(url=file.path(url,noresm), destfile=noresm,
               method="auto", quiet=FALSE, mode="w",
               cacheOK = TRUE)
  # Retrieve the data into "gcm" object
  gcm <- retrieve(file=file.path(~,noresm),param="tas",
                lon=c(-20,30),lat=c(40,90),plot=TRUE)
  # Download the air surface temperature (tas) for RCP 4.5 scenarios and
  # NorESM1-ME model from the climate explorer and store it in destfile. 
  # Compute the anomalies
  gcm.a <- as.anomaly(gcm,ref=c(1960:2001))
  map(gcm.a,projection="sphere")

## End(Not run)

metno/esd documentation built on April 24, 2024, 9:19 p.m.