cv_basin_daily_precip: Calculates basin-averaged daily precipitation

In CMIP6VisR: Visualization and Analysis of Coupled Model Intercomparison Project, Phase-6 (CMIP6) Hydroclimatic Data

Calculates basin-averaged daily precipitation

Description

Extracts the daily precipitation values from CMIP6 NetCDF files, and calculates the mean precipitation for a given basin for each time interval. The original files are in longitude-latitude projection, so the areas of the cells varies. The cell areas are used to weight the precipitation when computing the basin mean precipitation.

The CMIP6 data are arranged by zone in 9 files. As a given basin may lie over more than one zone, it may necessary to read in data from more than one NetCDF file when computing the basin mean precipitation.

Usage

cv_basin_daily_precip(
  netcdf_directory = ".",
  scenario = "pr_day_ACCESS-CM2_ssp126_r2i1p1f1_gn_20150101-21001231_cannc_SPQM_",
  basin_zone_area = NULL,
  temp_file = TRUE
)

Arguments

netcdf_directory	Required. Directory containing NetCDF files.
scenario	Required. Full name of scenario to be used. This is the file name omitting the zone number.
basin_zone_area	Required. A list object returned by cv_clip_basin() which contains the zone numbers to be used, the basin area within each zone, and rasters of each zone containing the area of each element.
temp_file	If TRUE (the default) then temporary files will be used when extracting the values from the NetCDF files. This option is slower than keeping all the values in memory (which is what occurs if temp_file = TRUE), but allows the function to work with very large basins, which may require more memory than is available.

Value

Reruns a data frame with 2 columns: date and precipitation. The date is a standard R date over the interval 2015-01-01 to 2100-12-31, and the precipitation is the basin mean value.

Author(s)

Kevin Shook

See Also

cv_clip_basin

Examples

# This function is marked to not be tested as it requires local copies of the CMIP6 data files
# which are many GB in size
library(terra)
az_raster <- cv_zone_area_raster()
fpath <- system.file("extdata", "07BF001.shp", package = "CMIP6VisR")
basin_vector <- vect(fpath)
basin_areas <- cv_clip_basin(az_raster, basin_vector)
netcdf_directory <- "."
values <- cv_basin_daily_precip(netcdf_directory = netcdf_directory,
                               basin_zone_area = basin_areas,
                               temp_file = FALSE)

CMIP6VisR documentation built on April 12, 2025, 1:54 a.m.