Generate Snow Cell Attributes

[jdduh]

The snow tool requires the following attributes to be associated with each snow cell for each daily snow source data.

1. Average elevation in feet (from 30 meters DEM)
2. Dominant aspect direction (4 and/or 8 directions, from 30 meters DEM)
3. % forested area (from 30 meters NLCD land cover)

The output are stored in tiff format. There are 3 snow data sources:

1. SNODAS - 800 x 800 meters spatial resolution
2. INSTAAR (aka Snow Today) - 500 x 500 meters spatial resolution
3. SWANN (University of Arizona SWE data) - 800 x 800 meters spatial resolution

The original SNODAS Tool already has implementation to generate the average elevation attribute for SNODAS cells.

[jdduh]

Definition of forested area:

We have a 2019 NLCD land cover service at: https://webservices.geog.pdx.edu/arcgis/rest/services/BAGIS_Databin/NLCD_2019_land_cover/ImageServer

The NLCD classes are:
0. Unclassified
11. Open Water - non-forested
12. Perennial Snow/Ice - non-forested
21. Developed, Open Space - non-forested
22. Developed, Low Intensity - non-forested
23. Developed, Medium Intensity - non-forested
24. Developed, High Intensity - non-forested
31. Barren Land - non-forested
41. Deciduous Forest
42. Evergreen Forest
43. Mixed Forest
52. Shrub/Scrub - non-forested
71. Herbaceous - non-forested
81. Hay/Pasture - non-forested
82. Cultivated Crops - non-forested
90. Woody Wetlands - non-forested
95. Emergent Herbaceous Wetlands - non-forested

Only 41, 42, and 43 are forested.

[jdduh]

Aspect Coding
4 directions
-1 flat area

1. N
2. E
3. S
4. W

8 directions
-1 flat area

1. N
2. NE
3. E
4. SE
5. S
6. SW
7. W
8. NW