Global soil type dataset for WRF-ARW model, based on HWSD version 2

Global soil type dataset, based on HWSD ("Harmonized World Soil Database", version 2.0), suitable for meteorological model WRF-ARW.

spatial resolution: 30 arc seconds by 30 arc seconds (about 1km)

original data (HWSD 2.0)

https://s3.eu-west-1.amazonaws.com/data.gaezdev.aws.fao.org/HWSD/HWSD2_RASTER.zip

https://s3.eu-west-1.amazonaws.com/data.gaezdev.aws.fao.org/HWSD/HWSD2_DB.zip

https://gaez.fao.org/pages/hwsd

documentation: Nachtergaele, Freddy, et al. Harmonized world soil database version 2.0. Food and Agriculture Organization of the United Nations, 2023. https://www.fao.org/3/cc3823en/cc3823en.pdf

the original 7 soil layers (0–20 cm, 20–40 cm, 40–60 cm, 60–80 cm, 80–100 cm, 100–150 cm and 150–200 cm) have been remapped to the 2 layers required by WRF (topsoil 0-30 cm, botsoil 30-200 cm)

the original Soil Mapping Units (SMU) have been remapped to the 16 soil categories used by WRF:

the depth-weighted averages of the content of clay, silt and sand lead to 12 texture-based categories (Sand, Loamy sand, Sandy loam, Silt loam, Silt, Loam, Sandy clay loam, Silty clay loam, Clay loam, Sandy clay, Silty clay, Clay), as defined by USDA;

category "Organic material" is assigned where the average content of organic carbon exceeds the threshold of 25%;

where the content of clay, silt and sand is not defined, HWSD special categories are mapped to the WRF last 3 categories, as follows:

"Water bodies" to "Water", 

"Rock outcrops" and "Rocky sublayers" to "Bedrock", 

"Land ice and glaciers", "Dunes/shifting sands", "Salt flats", and "Other" to "Other"

The dataset is provided in three ways:

two global files (SoilType_depthtocm.tif), one for each layer; format is GeoTIFF, compatible with convert_geotiff, a commandline utility for converting data from GeoTIFF to geogrid format used by WRF;

16 tiles, 8 for each layer, each covering 90 degrees by 90 degrees (SoilType_depthtocm_lontodeg_lattodeg.tif); format is GeoTIFF;

two compressed folders, hwsd_toplayer.zip and hwsd_bottomlayer.zip, each including 648 tiles in binary format and an "index" ASCII file, following the Geogrid data format and naming convention, as described here.

Soil categories are coded as follows

code
category

1
sand

2
loamy sand

3
sandy loam

4
silt loam

5
silt

6
loam

7
sandy clay loam

8
silty clay loam

9
clay loam

10
sandy clay

11
silty clay

12
clay

13
organic material

14
water

15
bedrock

16
other