Curve Number - FAO 

Parameter 

Curve Number - CCI Land Cover/SoilGrids Clay/Slope 

Represented range

Curve Number: 50 - 100

Description 

Parameter 

Curve Number - GCN250 Average antecedent conditions 


Represented range

Curve Number: 60 - 100

Description 

Parameter 

Curve Number - GCN250 Dry antecedent conditions 

Represented range

Curve Number: 30 - 80


Description 

Parameter 

Curve Number - GCN250 Wet antecedent conditions 

Represented range

Curve Number: 60 - 100

Description 

Parameter 

Runoff (average) - ECMWF Land / CCI LC / SRTM DEM  

Represented range

Runoff (average): 50 - 4,000 m3/ha

Description 

Parameter 

Total Available Water 

Represented range

TAW in the first meter:  80 -150 mm

Description 

FAO

Source data

Curve Number

Description 

The USDA curve-number (CN) method is fundamental for rainfall-runoff modeling. A global CN database is not currently available for geospatial hydrologic analysis at a resolution higher than 0.1°. We developed a globally consistent, gridded dataset defining CNs at the 250 m spatial resolution from new global land cover (300 m) and soils data (250 m). The resulting data product – GCN250 – represents runoff for a combination of the European space agency global land cover dataset for 2015 (ESA CCI-LC) resampled to 250 m and geo-registered with the hydrologic soil group global data product (HYSOGs250m) released in 2018. Our analysis indicated that medium to high runoff potential currently dominates the globe, with curve numbers ranging between 75 and 85. Global curve numbers were 62, 78, and 90 for dry, average, and wet antecedent runoff conditions, respectively. Australia has the highest runoff potential, while Europe has the lowest. Runoff ratios compare well with GLDAS. The potential application of this data includes hydrologic design, land management applications, flood risk assessment, and groundwater recharge modeling.


Spatial resolution

250 m

Temporal resolution