get_CRU_df: Download and create a data.table of CRU CL v. 2.0 climatology...
In adamhsparks/getCRUCL2.0: 'CRU' 'CL' v. 2.0 Climatology Client

View source: R/get_CRU_df.R

get_CRU_df

R Documentation

Download and create a data.table of CRU CL v. 2.0 climatology elements

Description

This function automates downloading and 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 use of this function.

Usage

get_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,
  cache = FALSE
)

get_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,
  cache = FALSE
)

Arguments

`pre`	Fetches precipitation (millimetres/month) from server and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`pre_cv`	Fetch cv of precipitation (percent) from server and returns it 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`	Fetches wet-days (number days with >0.1 millimetres rain per month) and returns it in the data frame? Defaults to `FALSE`.
`tmp`	Fetches temperature (degrees Celsius) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`dtr`	Fetches mean diurnal temperature range (degrees Celsius) and returns it in the data frame? Defaults to `FALSE`.
`reh`	Fetches relative humidity and returns it in the data frame, `TRUE`. Defaults to FALSE.
`tmn`	Calculates minimum temperature values (degrees Celsius) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`tmx`	Calculates maximum temperature (degrees Celsius) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`sunp`	Fetch sunshine, percent of maximum possible (percent of day length) and return it in the data frame? Defaults to `FALSE`.
`frs`	Fetches ground-frost records (number of days with ground- frost per month) and return it in the data frame? Defaults to `FALSE`.
`wnd`	Fetches 10m wind speed (metres/second) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`elv`	Fetches elevation (converted to metres) and returns it in the data frame, `TRUE`. Defaults to `FALSE`.
`cache`	Stores CRU CL v. 2.0 data files locally for later use. If `FALSE`, the downloaded files are removed when the R session is closed. To take advantage of cached files in future sessions, use `cache = TRUE` even after the initial download and caching. Defaults to `FALSE`.

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


# Download data and create a data frame of precipitation and temperature
# without caching the data files
CRU_pre_tmp <- get_CRU_df(pre = TRUE, tmp = TRUE)

head(CRU_pre_tmp)
CRU_pre_tmp

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