Daymet
In this file, the details of the dataset is explained.
Warning
The dataset files are divided between three different
spatial domains: 1) North America (na), 2) Peurto Rico (pr), and 3)
Hawaii (hi). For the moment, only the na domain is considered in
datatool.
Location of Dataset Files
The global Daymet dataset is located under the following directory
accessible from multiple clusters:
# DRAC Graham HPC locations
/project/rpp-kshook/Model_Output/Daymet_Daily_V4R1/data/ # rpp-kshook allocation
# UCalgary ARC HPC locations
/work/comphyd_lab/data/meteorological-data/daymet-v4r1-ornl # comphyd_lab allocation
# Perdue University Anvil HPC locations
/anvil/datasets/meteorological/ORNL_Daymet # community data storage
and the structure of the dataset hourly files is as following:
/path/to/dataset/files/
├── daymet_v4_daily_hi_dayl_1980.nc
├── daymet_v4_daily_hi_dayl_1981.nc
├── .
├── .
├── .
├── daymet_v4_daily_hi_dayl_2022.nc
├── .
├── .
├── .
├── daymet_v4_daily_hi_vp_1980.nc
├── .
├── .
├── .
├── daymet_v4_daily_hi_vp_2022.nc
├── .
├── .
├── .
├── daymet_v4_daily_{%domain}_{%variable}_{%year}.nc
├── .
├── .
├── .
├── daymet_v4_daily_na_dayl_1980.nc
├── .
├── .
├── .
├── daymet_v4_daily_na_vp_2022.nc
├── daymet_v4_daily_pr_dayl_1950.nc
├── .
├── .
├── .
└── daymet_v4_daily_pr_vp_2022.n
Coordinate Variables and Time-stamps
Coordinate Variables
The coordinate variables of the Daymet simulations are lon and
lat representing the longitude and latitude points, respectively.
The coordinate system is 2-dimensional and follows a Lambert Conformal
Conic projection system. ### Time-stamps The time-stamps are included in
the original files.
Dataset Variables
The NetCDF files of the dataset contain 7 variables. You may see a list of variables by browsing the dataset directory and listing the files.
Spatial Extent
The spatial resolutaion of Daymet gridded data is 1 \(km\). The
model files are divided between three different domains: 1) North
American (na), 2) Peurto Rico (pr), and 3) Hawaii (hi). Each domains
spatial extents are printed in the following table:
Number |
Domain |
Latitude extents |
Longitude extents |
|---|---|---|---|
1 |
|
|
|
2 |
|
|
|
3 |
|
|
|
Warning
As mentioned previously, only the na domain is
considered in the subsetting process of datatool.
Temporal Extent
The time-steps are daily and the temporal extent for each domain is listed in the following table:
Number |
Domain |
Time-step interval |
Start date |
End date |
|---|---|---|---|---|
1 |
|
daily |
|
|
2 |
|
daily |
|
|
3 |
|
daily |
|
|
Also, “[t]he Daymet calendar is based on a standard calendar year. All Daymet years have 1 - 365 days, including leap years. For leap years, the Daymet database includes leap day. Values for December 31 are discarded from leap years to maintain a 365-day year.”
Warning
As mentioned previously, only the na domain is
considered in the subsetting process of datatool.
Short Description on Daymet Variables
The variables currently available through the Daymet dataset and
their details are described in the table below, taken from the
source:
Variable Name |
Daymet Variable |
Unit |
Comments |
|---|---|---|---|
day length |
|
|
Duration of the daylight period in seconds per day. This calculation is based on the period of the day during which the sun is above a hypothetical flat horizon. |
precipitation |
|
|
Daily total precipitation in millimeters per day, sum of all forms converted to water-equivalent. Precipitation occurrence on any given day may be ascertained. |
shortwave radiation |
|
|
Incident shortwave radiation flux density in watts per square meter, taken as an average over the daylight period of the day. NOTE: Daily total radiation ( |
snow water equivalent |
|
|
Snow water equivalent in kilograms per square meter. The amount of water contained within the snowpack. |
maximum air temperature |
|
|
Daily maximum 2-meter air temperature in degrees Celsius. |
minimum air temperature |
|
|
Daily minimum 2-meter air temperature in degrees Celsius. |
water vapor pressure |
|
|
Water vapor pressure in pascals. Daily average partial pressure of water vapor. |
For a complete catalog of the dataset, see here.