Technical information

The Northern Circumpolar Soil Carbon Database version 2 (NCSCDv2) provides the spatial framework and the data needed to determine the organic carbon stocks in the soils of the permafrost region. The NCSCD contains many thousand of polygons, with each polygon containing one or more named soils or soil taxa that form the basis for determining the carbon stocks. For more detailed descriptions of the NCSCDv2 please refer to the publications on the NCSCDv2 start page (Hugelius et al., 2013a; 2013b).

Representative pedons for each soil taxa (Eurasia and Greenland) or named soil (Canada and United States) are selected. These pedons contain all the data needed to calculate soil carbon content. The data for the three layers that compose each soil (Canada and United States) are entered into the database and are used to calculate the carbon content of each named soil in the polygon while data from pedons of each soil taxa (Eurasia and Greenland) are used to calculate their carbon contents which are then entered into the database.

The soil organic carbon content (SOCC) was calculated for each of the three layers of each named soil (Canada and United States) and for the representative pedons for each soil taxa (Eurasia and Greenland) using the formula:

SOCC = C × BD × T × (1 − CF)

where C=organic carbon (% weight), BD=bulk density (g cm-3), T=depth of soil layer (0–300 cm) and CF=coarse fragments and/or ice content (% weight). The SOCC data are then stored in the database to be used for further calculations or to generate carbon content maps. In the vector database the SOCC is given in the unit kg C m-2 while it is given as hg C m-2 in the gridded datasets.

The soil organic carbon mass (SOCM) was then determined by multiplying the SOCC of the specific soil by the area of each such soil component in the polygon. These data provide information on the SOCM of each soil in each permafrost zone in the northern circumpolar region and for the production of SOCM maps. Please note: SOC and AREA Attributes were calculated by projecting each region into an Azimuthal equal area projection relevant to that region. For details regarding the parameters included in the polygon attribute tables of shape files and gridded datasets, please refer to tables in the publications on the NCSCDv2 start page (Hugelius et al., 2013a; 2013b).

Projection parameters

Lambert Azimuthal Equal Area Projection
Datum WGS84, Units METERS

Radius of Sphere of Reference 6370997.00000
Longitude of Center of Projection 0° 0' 0.00"
Latitude of Center of Projection 90° 0' 0.00"
False Easting 0.0000
False Northing 0.0000

Data format (Polygon attribute table)

DESCRIPTIONITEM NAMEINOUTTYPEDEC
Area of Polygon (m2)AREA412F3
Permimeter (m)PERIMETER412F3
Internal ESRI #MONGOLIAJAN07#45B-
Internal ESRI IDMONGOLIAJAN07-ID45B-
Link to original sourceName found in original source i.e SMU/MUID
Gelisol % of polygonGELISOL_PCT33I-
Histosol % of polygonHISTOSOL_PCT33I-
Mollisol % of polygonMOLLISOL_PCT33I-
Vertisol % of polygonVERTISOL_PCT33I-
Aridisol % of polygonARIDISOL_PCT33I-
Andisol % of polygonANDISOL_PCT33I-
Entisol % of polygonENTISOL_PCT33I-
Ultisol % of polygonULTISOL_PCT33I-
Spodosol % of polygonSPODOSOL_PCT33I-
Inceptisol % of polygonINCEPTISOL_PCT33I-
Alfisol % of polygonALFISOL_PCT33I-
Natric soils % of polygon NATRIC_PCT33I-
Aqu soils % of polygonAQU_PCT33I-
Water % of polygonWATER_PCT33I-
Rockland % of polygonROCKLAND_PCT33I-
Glacier % of polygonGLACIER_PCT33I-
Miscellaneous % of polygonMISC_PCT33I-
Gelisol — Turbel % of polygonTURBEL_PCT33I-
Gelisol — Orthel % of polygonORTHEL_PCT33I-
Gelisol — Histel % of polygonHISTEL_PCT33I-
Total TOTAL_PCT33I-
Permafrost extentEXTENT44C-
Gelisol area (m2)GE_AREA1616N1
Alfisol area (m2)AL_AREA1616N1
Entisol area (m2)EN_AREA1616N1
Inceptisol area (m2)IN_AREA1616N1
Spodosol area (m2)SP_AREA1616N1
Natric soils area (m2)NA_AREA1616N1
Aqu soil area (m2)AQ_AREA1616N1
Vertisol area (m2)VE_AREA1616N1
Mollisol area (m2) MO_AREA1616N1
Histosol area (m2)HI_AREA1616N1
Aridisol area (m2)AR_AREA1616N1
Andisol area (m2)AN_AREA1616N1
Ultisolarea (m2)UL_AREA1616N1
Turbel area (m2)GET_AREA1616N1
Orthel area (m2)GEO_AREA1616N1
Histel area (m2)GEH_AREA1616N1
Rockland area (m2)ROCK_AREA1616N1
Glacier area (m2)GLACIER_AREA1616N1
Miscellaneous area (m2)MISC_AREA1616N1
SOCM 30cm depth Gelisol (kg)GE_30SOCM1616N1
SOCM 30cm depth Alfisol (kg)AL_30SOCM1616N1
SOCM 30cm depth Entisol (kg)EN_30SOCM1616N1
SOCM 30cm depth Inceptisol(kg)IN_30SOCM1616N1
SOCM 30cm depth Spodosol(kg)SP_30SOCM1616N1
SOCM 30cm depth Natric (kg)NA_30SOCM1616N1
SOCM 30cm depth Aqu soils(kg)AQ_30SOCM1616N1
SOCM 30cm depth Vertisol (kg)VE_30SOCM1616N1
SOCM 30cm depth Mollisol (kg)MO_30SOCM1616N1
SOCM 30cm depth Histosol (kg)HI_30SOCM1616N1
SOCM 30cm depth Aridisol (kg)AR_30SOCM1616N1
SOCM 30cm depth Andisol (kg)AN_30SOCM1616N1
SOCM 30cm depth Ultisol (kg)UL_30SOCM1616N1
SOCM 30cm depth Turbel (kg)GET_30SOCM1616N1
SOCM 30cm depth Orthel (kg)GEO_30SOCM1616N1
SOCM 30cm depth Histel (kg)GEH_30SOCM1616N1
SOCM 100cm depth Gelisol (kg)GE_100SOCM1616N1
SOCM 100cm depth Alfisol (kg)AL_100SOCM1616N1
SOCM 100cm depth Entisol (kg)EN_100SOCM1616N1
SOCM 100cm depth Inceptisol (kg)IN_100SOCM1616N1
SOCM 100cm depth Spodosol (kg)SP_100SOCM1616N1
SOCM 100cm depth Natric (kg)NA_100SOCM1616N1
SOCM 100cm depth Aqu (kg)AQ_100SOCM1616N1
SOCM 100cm depth Vertisol (kg)VE_100SOCM1616N1
SOCM 100cm depth Mollisol (kg)MO_100SOCM1616N1
SOCM 100cm depth Histosol (kg)HI_100SOCM1616N1
SOCM 100cm depth Aridisol (kg)AR_100SOCM1616N1
SOCM 100cm depth Andisol (kg)AN_100SOCM1616N1
SOCM 100cm depth Ultisol (kg)UL_100SOCM1616N1
SOCM 100cm depth Turbel (kg)GET_100SOCM1616N1
SOCM 100cm depth Orthel (kg)GEO_100SOCM1616N1
SOCM 100cm depth Histel (kg)GEH_100SOCM1616N1
SOCC 30cm depth polygon (kg/m2)SOCC_30CM88N1*
SOCC 100cm depth polygon (kg/m2)SOCC_100CM88N1
Soil Area (m2)SOIL_AREA1616N1
SOCM 30cm depth polygon (kg)SOCM_30CM1616N1*
SOCM 100cm depth polygon (kg)SOCM_100CM1616N1

* SOCC (Soil Organic Carbon Content)
* SOCM (Soil Organic Carbon Mass)