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.
The global Daymet dataset is located under the following directory accessible from Digital Research Alliance of Canada (DRA) Graham cluster:
/project/rpp-kshook/Model_Output/Daymet_Daily_V4R1/data/
and the structure of the dataset hourly files is as following:
/project/rpp-kshook/Model_Output/Daymet_Daily_V4R1/data/
├── 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.nThe 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.
The time-stamps are included in the original files.
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.
The spatial resolutaion of Daymet gridded data is 1
| Number | Domain | Latitude extents | Longitude extents |
|---|---|---|---|
| 1 | na |
+6.08° to +83.79° |
-180° to +180° |
| 2 | pr |
+16.85° to +19.93° |
-67.97° to -64.13° |
| 3 | hi |
+17.96° to +23.51° |
-160.30° to -154.78° |
Warning
As mentioned previously, only the na domain is considered in the subsetting process of datatool.
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 | na |
daily | 1980-01-01 |
2022-12-31 |
| 2 | pr |
daily | 1950-01-01 |
2022-12-31 |
| 3 | hi |
daily | 1980-01-01 |
2022-12-31 |
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.
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 | dayl |
s/day |
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 | prcp |
mm/day |
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 rdiation | srad |
W/m2 |
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 (MJ/m2/day) can be calculated as follows: ((srad (W/m2) * dayl (s/day)) / l,000,000) |
| snow water equivalent | swe |
kg/m2 |
Snow water equivalent in kilograms per square meter. The amount of water contained within the snowpack. |
| maximum air temperature | tmax |
deg C |
Daily maximum 2-meter air temperature in degrees Celsius. |
| minimum air temperature | tmin |
deg C |
Daily minimum 2-meter air temperature in degrees Celsius. |
| water vapor pressure | vp |
Pa |
Water vapor pressure in pascals. Daily average partial pressure of water vapor. |
For a complete catalog of the dataset, see here.