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Data Set ID:
GGD631

Shallow Borehole Temperatures, Ilulissat, Greenland, Version 1

This data set contains borehole temperatures from Ilulissat, west Greenland (69°N, 51°N, 44 m asl), recorded from 21 thermistors at depths of 0.25 m, 0.5 m, 0.75 m, 1 m, 1.25 m, 1.5 m, 1.75 m, 2 m, 2.5 m, 3 m, 3.5 m, 4 m, 4.5 m, 5 m, 6 m, 7 m, 8 m, 9 m, 11 m, 13 m, and 15 m below the surface. Snow depth, snow extent, and surface air temperature were also recorded. Thermometers recorded temperatures once a day from 06 November 1968 to 15 June 1982; however, this data set only contains bi-weekly averages. Data are in tab-delimited ASCII text format and are available via FTP.

Geographic Coverage

Parameter(s):
  • Frozen Ground > Active Layer
  • Frozen Ground > Soil Temperature
  • Soils > Soil Temperature
Spatial Coverage:
  • N: 69, S: 69, E: -51, W: -51

Spatial Resolution: Not Specified
Temporal Coverage:
  • 6 November 1968 to 15 June 1982
Temporal Resolution: Not specified
Data Format(s):
  • ASCII Text
Platform(s) Not specified
Sensor(s): Not specified
Version: V1
Data Contributor(s): Ole B. Olesen
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.

Olesen, O.B 2003. Shallow Borehole Temperatures, Ilulissat, Greenland, Version 1. [Indicate subset used]. Copenhagen, Denmark. Greenlandic Geological Survey, GEUS. [Date Accessed].

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Detailed Data Description

In 1967, the Greenlandic Geological Survey (GEUS) started a program to monitor soil temperatures in permafrost and seasonal frost areas in West Greenland as part of the UNESCO International Hydrological Decade program (Olesen 1967avan Tatenhove and Olesen 1994). That same year, Ole Olesen established a permafrost station in Ilulissat (formerly Jakobshavn, 69°N, 51°N, 44 m asl). After 1982, the GGU ceased monitoring the thermal properties of permafrost, in part, because several thermistors stopped working.

Olesen installed 21 platinum resistance thermometers in boreholes every 0.25 m down to 2 m below the surface, every 50 cm down to 5 m, every 1 m between 5 m and 9 m, and every 2 m from 9 m to 15 m. The thermistors consisted of platinum wire with a resistance of 100.00 ± 0.1 &Omega at 0.25°C. They were mounted in pertinax tubes, each holding three thermistors at different levels.

Format

Data are in tab-delimited ASCII text format. The file "ggd631_soiltmp_iluliss.txt" contains columns for date, raw borehole temperatures at depths ranging from 0.25 m to 15 m, maximum and minimum daily air temperatures, snow index (1-4), and snow depth (cm). The snow index indicates snow extent in quartiles (1 = 25%, 2 = 50%, 3 = 75%, 0 = no data).

The date format is "ddmmyyyy." The date is left-justified when days are single digits. For example, "61111968" is 6 November 1968.

Missing values are indicated by "-999." Corrected temperatures take into account calibration factors found in "ggd631_sensors_iluliss.txt." This file lists the sensors with corresponding depths (m) and calibration factors (°C). Some thermistors stopped working during the period of data collection.

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File Naming Convention

ggd631_sensors_iluliss.txt
ggd631_soiltmp_iluliss.txt

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File Size

ggd631_sensors_iluliss.txt: 1 KB
ggd631_soiltmp_iluliss.txt: 41 KB

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Spatial Coverage

Data were collected from a station in Ilulissat, west Greenland, at approximately 69°N, 51°W. The station was located 32 m east of the heliport control house, at approximately 44 m asl, in an area with about 8 m of sediment above the bedrock. The ground around the station was horizontal and completely saturated with water. About 10 cm of grass and moss grew in the station area. A peat layer 20 m to 30 cm thick underlied the vegetation. A blue-gray silt sediment with some stones and sandy layers underlied the peat layer down to the bedrock surface, at approximately 7.8 m to 9.4 m below the surface. The bedrock was gneiss. It was heavily weathered in the top 3 m to 4 m. Permafrost was present at 2 m depth.

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Temporal Coverage

Thermometers recorded temperatures once a day from November 1968 to June 1982; however, this data set only contains bi-weekly averages.

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Software and Tools

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Data Acquisition and Processing

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References and Related Publications

Contacts and Acknowledgments

Ole B. Olesen
Geological Survey of Denmark and Greenland
Øster Voldgade 10
1350 København K
Denmark

Acknowledgments: 

When using these data, please acknowledge that they are the property of the Danish and Greenlandic Geological Survey (GEUS). A cooperative agreement with GEUS was signed before any access was granted to the hardcopy data digitized by Niels Foged and his students at Artek.

Document Information

Please cite these data as follows:

Olesen, O.B. 2003. Shallow Borehole Temperatures, Ilulissat, Greenland. Copenhagen, Denmark: Greenlandic Geological Survey (GEUS). Distributed by National Snow and Ice Data Center. Digital Media.

Document Creation Date:

March 2003

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