create_CRU_df: Create a data.table of CRU CL v. 2.0 climatology elements...
In adamhsparks/getCRUCL2.0: 'CRU' 'CL' v. 2.0 Climatology Client

View source: R/create_CRU_df.R

create_CRU_df

R Documentation

Create a data.table of CRU CL v. 2.0 climatology elements from local disk files

Description

Automates importing CRU CL v.2.0 climatology data and creates a data.table of the data. If requested, minimum and maximum temperature may also be automatically calculated as described in the data readme.txt file. Data may be cached for later use by this function, saving time downloading files in future using this function. This function can be useful if you have network connection issues that mean automated downloading of the files using R does not work properly.

Usage

create_CRU_df(
  pre = FALSE,
  pre_cv = FALSE,
  rd0 = FALSE,
  tmp = FALSE,
  dtr = FALSE,
  reh = FALSE,
  tmn = FALSE,
  tmx = FALSE,
  sunp = FALSE,
  frs = FALSE,
  wnd = FALSE,
  elv = FALSE,
  dsn
)

create_cru_df(
  pre = FALSE,
  pre_cv = FALSE,
  rd0 = FALSE,
  tmp = FALSE,
  dtr = FALSE,
  reh = FALSE,
  tmn = FALSE,
  tmx = FALSE,
  sunp = FALSE,
  frs = FALSE,
  wnd = FALSE,
  elv = FALSE,
  dsn
)

Arguments

`pre`	Loads precipitation (millimetres/month) from server and returns in the data frame, `TRUE`. Defaults to `FALSE`.
`pre_cv`	Loads cv of precipitation (percent) from server and returns in the data frame, `TRUE`. Defaults to `FALSE`. NOTE. Setting this to `TRUE` will always results in pre being set to `TRUE` and returned as well.
`rd0`	Loads wet-days (number days with >0.1 millimetres rain per month) and returns in the data frame, `TRUE`. Defaults to `FALSE`.
`tmp`	Loads temperature (degrees Celsius) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`dtr`	Loads mean diurnal temperature range (degrees Celsius) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`reh`	Loads relative humidity and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`tmn`	Calculate minimum temperature values (degrees Celsius) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`tmx`	Calculate maximum temperature (degrees Celsius) and return it in the data frame, `TRUE`. Defaults to `FALSE`.
`sunp`	Loads sunshine, percent of maximum possible (percent of day length) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`frs`	Loads ground-frost records (number of days with ground- frost per month) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`wnd`	Load 10 m wind speed (metres/second) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`elv`	Loads elevation (converted to metres) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`dsn`	Local file path where CRU CL v.2.0 .dat.gz files are located.

Value

A data.table::data.table object of CRU CL v. 2.0 climatology elements.

Nomenclature and Units

pre: precipitation (millimetres/month)

cv: cv of precipitation (percent)

rd0: wet-days (number days with >0.1 millimetres rain per month)
tmp: mean temperature (degrees Celsius)
dtr: mean diurnal temperature range (degrees Celsius)
reh: relative humidity (percent)
sunp: sunshine (percent of maximum possible (percent of day length))
frs: ground-frost (number of days with ground-frost per month)
wnd: 10 metre windspeed (metres/second)
elv: elevation (automatically converted to metres)

For more information see the description of the data provided by CRU, https://crudata.uea.ac.uk/cru/data/hrg/tmc/readme.txt

Author(s)

Adam H. Sparks, adamhsparks@gmail.com

Source

pre: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_pre.dat.gz
rd0: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_rd0.dat.gz
tmp: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_tmp.dat.gz
dtr: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_dtr.dat.gz
reh: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_reh.dat.gz
sunp: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_sunp.dat.gz
frs: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_frs.dat.gz
wnd: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_wnd.dat.gz, areas originally including Antarctica are removed.
elv: https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_elv.dat.gz, values are converted from kilometres to metres.

This package crops all spatial outputs to an extent of ymin = -60, ymax = 85, xmin = -180, xmax = 180.

References

New, Mark, et al. "A high-resolution data set of surface climate over global land areas." Climate research 21.1 (2002): 1-25. https://crudata.uea.ac.uk/cru/data/hrg/tmc/new_et_al_10minute_climate_CR.pdf

Examples


# Create a data frame of temperature from locally available files in the
# tempdir() directory.

download.file(
  url = "https://crudata.uea.ac.uk/cru/data/hrg/tmc/grid_10min_tmp.dat.gz",
  destfile = file.path(tempdir(), "grid_10min_tmp.dat.gz")
)

CRU_tmp <- create_CRU_df(tmp = TRUE, dsn = tempdir())

CRU_tmp

adamhsparks/getCRUCL2.0 documentation built on Dec. 21, 2024, 4:32 a.m.