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Data Set ID:
GGD9

Seasonal and annual dynamics of frozen ground, central highland of Iceland, Version 1

This dataset documents a nine-year study to investigate the seasonal and annual dynamics of frozen ground and explore the relationship with environmental factors. The presence/absence of frozen ground and active layer thickness were recorded three times over the growing season (4-7 July, 1-4 August, and 20-24 August) at 51 permanent points in different plant communities and on 12 palsas (Thorhallsdottir 1996, p. 237). Sample size is variable: 33 permanent measurement stations in 1983, 29 in 1984, 63 in 1985-1991. Active layer depth measurement sites averaged 51 over the span of the data set. Data include mean active layer depth (and standard error) in early July and early August (for palsas and with palsas excluded); monthly degree days above zero, precipitation, snow depth, and frost degree days (i.e., below zero.) Data are presented on the CAPS Version 1.0 CD-ROM, June 1998.

Geographic Coverage

Parameter(s):
  • Frozen Ground > Active Layer
  • Atmospheric Temperature > Degree Days
  • Frozen Ground > Permafrost
  • Frozen Ground > Seasonally Frozen Ground
  • Snow/Ice > Snow Depth
Spatial Coverage:
  • N: 64.5, S: 64.5, E: -18.667, W: -18.667

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 January 1983 to 31 December 1991
Temporal Resolution: Not specified
Data Format(s):
  • Microsoft Excel
  • ASCII Text
Platform(s) Not specified
Sensor(s): Not specified
Version: V1
Data Contributor(s): Thora Ellen Thorhalsdottir
Data Citation

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Thorhalsdottir, T.E. 1998. Seasonal and annual dynamics of frozen ground, central highland of Iceland, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. [Date Accessed].

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Notice: 

This data set was first published on the 1998 CAPS CD.
The text for this document was taken unchanged from that CD.

Detailed Data Description

The results of a "... 9-year study ... to investigate the seasonal and annual dynamics of frozen ground and explore the relationship with environmental factors. The presence/absence of frozen ground and active layer thickness were recorded three times over the growing season (4-7 July, 1-4 August, and 20-24 August) at 51 permanent points in different plant communities and on 12 palsas." (Thorhallsdottir 1996, p. 237)

Frozen ground and active layer depth data, with monthly thawing and freezing degree days, precipitation and snow depth, for 1983-1991. Here are the total numbers of permanent stations where measurements were made: 33 stations in 1983, 59 stations in 1984, 63 stations in 1985-91. For the active layer depth they were divided into palsa tops (2 in 1983 but 12 after that) and all other (including several different plant communities, 51 stations for most years).

Format

Data are in text format.
 

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File Naming Convention
  • Columns:
    • Year
    • kjuly = proportion of stations with frozen ground 4-7 July
    • kjulaug = ditto on 1-4 August
    • kaugust = ditto on 20-24 August
    • aldjulyo = mean active layer depth (cm) on 4-7 July, palsas excluded
    • sejulyo = standard error of the mean for the above
    • aldjulyp and sejulyp are as above but for palsas only
    • aldjao = active layer depth (cm) on 1-4 August, palsas excluded
    • sealdjao = s.e. of above
    • aldjap and sealdjap are as above but for palsas only
    • aldaugo = mean active layer depth (cm) on 20-24 August, palsas excluded
    • sealdaugo = s.e. of above
    • aldaugp and sealdaugp are as above but for palsas only
    • kyrbefore = proportion of stations with frozen ground in late August of the year before
    • dd5, dd6, dd7 and dd8 are monthly degree days above zero
    • precip56, precip7.....etc precipitation (mm)
    • snow9....snow12 is snowdepth in cm for those months
    • frdd is frost degree days, i.e. below zero
  • Format: 
    Year: yyyy 
    All other columns: nnn.nnnnn
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Spatial Coverage

Location: Thjorsarver, Central Highland, Iceland
Latitude: 63° 30' N
Longitude: 18° 40' W

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Temporal Coverge

Time period: 1982 - 1992

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Software and Tools

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Data Acquisition and Processing

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Contacts and Acknowledgments

Thora Ellen Thorhallsdottir
Institute of Biology, University of Iceland

Document Information

Please cite these data as follows:

Thorhallsdottir, T.E., 1998. Seasonal and annual dynamics of frozen ground, central highland of Iceland. In: International Permafrost Association, Data and Information Working Group, comp. Circumpolar Active-Layer Permafrost System (CAPS), version 1.0. CD-ROM available from National Snow and Ice Data Center, nsidc@kryos.colorado.edu. Boulder, Colorado: NSIDC, University of Colorado at Boulder.

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