Daymet
Daymet provides daily, gridded weather data at a 1 km resolution from 1980 to the present. It’s based on modeled estimates and is ideal for long-term climate trend analysis across space and time.
DEVISE uses Daymet to summarize the following variables across selected temporal and spatial layers..
Precipitation (prcp)
Daily total precipitation (rain+snow in mm) calculated on a cell by cell basis on three temporal scales (daily, monthly, and annually).
- Daily data represent the raw value from DAYMET. (Averaged for spatial layer units and raw values for a specific cell)
\[\text{Daily prcp area} = \frac{\sum_{j=0}^{n} ({prcp}_j)}{n}\]
\[\text{Daily prcp cell} = \text{prcp}_{j}\]
\(j\): current cell | \(n\): # of cells in the spatial layer unit
- Monthly data are the summation of each day’s value within the month
\[\text{Monthly prcp} = \sum_{i=1}^{d} \text{daily prcp}_i \] \(d\): # of days in the month | \(i\): Current day (iterator)
- Annual data are the summation of each day’s value within the water year (Oct 1 - Sep 30 of the given year, e.g. 10/01/1981 - 09/30/1982 would be labeled as 01/01/1982).
\[\text{Annual prcp} = \sum_{i=1}^{d} \text{daily prcp}_i \] \(d\): # of days in the water year | \(i\): Current day (iterator)
Snow Water Equivalent (swe)
Daily SWE (Snow Water Equivalent; the amount of water contained within the snowpack.) calculated on a cell by cell basis on three temporal scales (daily, monthly, and annually).
- Daily data represent the raw value from DAYMET(Averaged for spatial layer units and raw values for a specific cell)
\[\text{Daily swe area} = \frac{\sum_{j=0}^{n} ({swe}_j)}{n}\] \[\text{Daily swe cell} = \text{swe}_{j}\]
\(j\): current cell | \(n\): total cells in spatial layer unit
- Monthly data are the average of each day’s value within the month
\[\text{Monthly swe} = \frac{\sum_{i=1}^{d} \text{daily swe}_i}{d} \]
\(d\): # of days in the month | \(i\): Current day (iterator)
- Annual data are the average of each day’s value within the water year (Oct 1 - Sep 30 of the given year, e.g. 10/01/2003 - 09/30/2004 would be labeled as 01/01/2004).
\[\text{Annual swe} = \frac{\sum_{i=1}^{d} \text{daily swe}_i}{d} \] \(d\): # of days in the water year | \(i\): Current day (iterator)
Maximum Temperature (tmax)
Daily maximum temperature (Celsius) calculated on a cell by cell basis on three temporal scales (daily, monthly, and annually).
- Daily data represent the raw value from DAYMET(Averaged for spatial layer units and raw values for a specific cell)
\[\text{Daily tmax area} = \frac{\sum_{j=0}^{n} ({tmax}_j)}{n}\] \[\text{Daily tmax cell} = \text{tmax}_{j}\]
\(j\): current cell | \(n\): total cells in spatial layer unit
- Monthly data are the average of each day’s value within the month
\[\text{Monthly tmax} = \frac{\sum_{i=1}^{d} \text{daily tmax}_i}{d} \]
\(d\): # of days in the month | \(i\): Current day (iterator)
Annual data are the average of each day’s value within the water year (Oct 1 - Sep 30 of the given year, e.g. 10/01/1981 - 09/30/1982 would be labeled as 01/01/1982).
\[\text{Annual tmax} = \frac{\sum_{i=1}^{d} \text{daily tmax}_i}{d} \]
\(d\): # of days in the water year | \(i\): Current day (iterator)
Minimum Temperature (tmin)
Daily minimum temperature (Celsius) calculated on a cell by cell basis on three temporal scales (daily, monthly, and annually).
- Daily data represent the raw value from DAYMET(Averaged for spatial layer units and raw values for a specific cell)
\[\text{Daily tmin area} = \frac{\sum_{j=0}^{n} ({tmin}_j)}{n}\] \[\text{Daily tmin cell} = \text{tmin}_{j}\]
\(j\): current cell | \(n\): total cells in spatial layer unit
- Monthly data are the average of each day’s value within the month
\[\text{Monthly tmin} = \frac{\sum_{i=1}^{d} \text{daily tmin}_i}{d} \]
\(d\): # of days in the month | \(i\): Current day (iterator)
Annual data are the average of each day’s value within the water year (Oct 1 - Sep 30 of the given year, e.g. 10/01/1981 - 09/30/1982 would be labeled as 01/01/1982).
\[\text{Annual tmin} = \frac{\sum_{i=1}^{d} \text{daily tmin}_i}{d} \]
\(d\): # of days in the water year | \(i\): Current day (iterator)