Circumarctic wetland dataset based on ENVISAT ASAR Global Monitoring Mode, 2005-2011, Panarctic

Widhalm, Barbara; Bartsch, Annett; Heim, Birgit

A circumpolar representative and consistent wetland map is required for a range of applications ranging from upscaling of carbon fluxes and pools to climate modelling and wildlife habitat assessment. Currently available data sets lack sufficient accuracy and/or thematic detail in many regions of the Arctic. Synthetic aperture radar (SAR) data from satellites have already been shown to be suitable for wetland mapping. Envisat Advanced SAR (ASAR) provides global medium-resolution data which are examined with particular focus on spatial wetness patterns in this study. It was found that winter minimum backscatter values as well as their differences to summer minimum values reflect vegetation physiognomy units of certain wetness regimes. Low winter backscatter values are mostly found in areas vegetated by plant communities typically for wet regions in the tundra biome, due to low roughness and low volume scattering caused by the predominant vegetation. Summer to winter difference backscatter values, which in contrast to the winter values depend almost solely on soil moisture content, show expected higher values for wet regions. While the approach using difference values would seem more reasonable in order to delineate wetness patterns considering its direct link to soil moisture, it was found that a classification of winter minimum backscatter values is more applicable in tundra regions due to its better separability into wetness classes. Previous approaches for wetland detection have investigated the impact of liquid water in the soil on backscatter conditions. In this study the absence of liquid water is utilized. Owing to a lack of comparable regional to circumpolar data with respect to thematic detail, a potential wetland map cannot directly be validated; however, one might claim the validity of such a product by comparison with vegetation maps, which hold some information on the wetness status of certain classes. It was shown that the Envisat ASAR-derived classes are related to wetland classes of conventional vegetation maps, indicating its applicability; 30% of the land area north of the treeline was identified as wetland while conventional maps recorded 1-7%.


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Widhalm, Barbara

Metadata Access

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Data and Resources

Additional Info

Field Value
Identifier DOI: 10.1594/PANGAEA.840548
Project(s) Changing Permafrost in the Arctic and its Global Effects in the 21st Century
Institute Vienna University of Technology, Vienna, Austria
Publication Date 2014-12-01
Version 1.0
Product Circumpolar wetness level map
Sensor Envisat ASAR
  1. TUW_ASAGM_WWN_001_2005_2011_CIR.tif
Variables [Units]
  1. NETCDF_VARNAME: wetness level (1 - wet, 2 - medium, 3 - dry)
Region Circum-Arctic
Spatial Reference EPSG:4326 WGS 84
Spatial Resolution 1 km
Spatial Coverage Latitude 60.00 to 90.00, Longitude -180.00 to 180.00
Temporal Coverage 2005-2011
Temporal Resolution
Format netCDF, geotiff
Is Supplement To

Widhalm, B et al. (2015): A novel approach for the characterization of tundra wetland regions with C-band SAR satellite data. International Journal of Remote Sensing, 36(22), 5537-5556,

Related to

Bartsch, Annett; Sabel, Daniel; Wagner, Wolfgang; Park, Sang-Eun (2011): Considerations for derivation and use of soil moisture data from active microwave satellites at high altitudes. IGARSS 2011, IEEE International Geoscience and Remote Sensing Symposium, 24-29 July 2011, Vancouver, British Columbia, Canada, 3132-3135,

Bartsch, Annett; Wagner, Wolfgang; Scipal, Klaus; Pathe, Carsten; Sabel, Daniel; Wolski, P (2009): Global monitoring of wetlands – the value of ENVISAT ASAR Global mode. Journal of Environmental Management, 90(7), 2226-2233,

Dataset extent

Map tiles and data by OpenStreetMap, under CC BY SA.