R/download_daymet.R

In ncsuSEAL/sealR: A number of helpful functions for SEAL at NCSU

#************************************************************************
# Description: Download Daymet climate data. Actually, this process is provided by the
#              "daymetr" package, thanks to the authors of it. 
#              Users can read their full documentation at: https://cran.r-project.org/web/packages/daymetr/daymetr.pdf
# Author: Xiaojie Gao
# Date: 2020-11-26
#************************************************************************
# library(daymetr)


# user inputs
# ==============================================================
startyr <- 1980
endyr <- 1982

# VARIABLES - Daymet variables - tmin and tmax are used as examples, variables should be space separated.
# The complete list of Daymet variables is: tmin, tmax, prcp, srad, vp, swe, dayl
var <- c("tmin", "tmax")

# VARIABLES - Spatial subset - bounding box in decimal degrees.
north <- 36.61
west <- -85.37
east <- -81.29
south <- 33.57

# output folder
# out_dir <- "Z:/Gao/"
# ==============================================================


# Actually, there are several download options provided in the "daymetr" package, here I only include a simpliest and commonly used one.
# download_daymet_ncss(location = c(north, west, south, east), start = startyr, end = endyr, param = var, frequency = "daily", path = out_dir)

# Other download functions include: 
# - download_daymet(): download single location daymet data.
# - download_daymet_batch(): download several single locations daymet data, locations are specified by a batch file.
# - download_daymet_tiles: download gridded daymet data tiles.

# Full documentation can be found here: https://cran.r-project.org/web/packages/daymetr/daymetr.pdf


# They also provide a function to convert the downloaded daymet netCDF file to tiff format, although I don't recommend doing so.
# net2cdf(path = out_dir, files = "tmin_daily_1980_ncss.nc")