README.md

In bsmity13/snowdl: Download Various Sources of Snow Data

snowdl

The goal of snowdl is to make it easy to download snow data (e.g., snow depth, snow density, snow-water equivalent) from various sources (see below).

Installation

Install the development version from GitHub with:

# install.packages("devtools")
devtools::install_github("bsmity13/snowdl")

This package is not yet operational. Check back soon for progress!

Available data sources

Sorted alphabetically by dataset name

| Dataset | Source | Link | Citation | | :--------------- | :----- | :-------------------------------------------------------------------------------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------- | | Daymet v4 | NASA | ORNL DAAC | Thornton et al. 2020 | | ERA5-Land Hourly | ECMWF | ERA5-Land | DOI: 10.24381/cds.e2161bac | | SNODAS | NOAA | NSIDC | DOI: 10.7265/N5TB14TC |

Important Notes

• Daymet is probably not a great source for SWE. Based on my reading, they treat it more like a nuisance parameter than a quanity of interest. See this link for their Snow Water Equivalent Clarification. Note, this clarification was made in reference to V3, but still applies based on newest literature for V4.

• Further, Daymet has (apparently) different units for SWE than other sources (but not really). Daymet uses kg/m^2, while other sources use m (depth if snow was melted). To convert, multiply by area of the pixel (kg/m^2 * m^2/1 = kg) to get mass of water, convert to cubic meters (1 kg = 1 L H2O = 0.001 m^3), and then get depth by dividing by area (m^3/1 * 1/m^2 = m). Perhaps more useful to have units in mm, so again multiply by 0.001 m = 1 mm. * Note Daymet comes with lcc projection and units = m. Resolution is 1000 x 1000, so area is 1e6 m^2. * Therefore, conversion becomes x * 1e6 * 0.001 * 0.001. All conversions cancel and resulting units are mm. * To be clear, kg/m^2 = mm in this case.

Package Status/To-dos

• [x] Basic functionality
  • [x] Download Daymet and process
  • [x] Download ERA5 and process
  • [x] Download SNODAS and process
• [ ] User-friendly wrappers
  • [ ] Iterate over dates
  • [ ] Complete entire workflow in tempdir()
• [ ] Other data sources?
• [ ] Vignettes
  • [ ] Overview/Quickstart using wrapper functions
  • [ ] In-depth using basic functionality

bsmity13/snowdl documentation built on Feb. 24, 2024, 9:03 p.m.