Documentation Revision Date: 2018-04-17
Data Set Version: 1
Summary
There is one data file with this dataset in comma-separated (.csv) format.
Figure 1. Locations of thaw depth measurement sites. Three of the locations are paired unburned-burn sites and appear as one symbol.
Citation
Natali, S., S. Ludwig, C. Minions, and J.D. Watts. 2018. ABoVE: Thaw Depth at Selected Unburned and Burned Sites Across Alaska, 2016-2017. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1579
Table of Contents
- Data Set Overview
- Data Characteristics
- Application and Derivation
- Quality Assessment
- Data Acquisition, Materials, and Methods
- Data Access
- References
Data Set Overview
This dataset provides thaw depth measurements made at seven locations across Alaska, during August 2016 and June and September 2017. Three of the locations are paired unburned-burned sites. At each site, three 30-meter transects were established and thaw depth was measured at 1-meter increments along each transect using a 1.15 m T-shaped thaw depth probe. Locations were selected to investigate fire disturbance, to span the range of permafrost regions from continuous to sporadic, and to cover vegetation types from boreal forests, tussock tundra, upland willow/herbaceous scrub, and lowland fen and wet tundra sites across Alaska.
Project: Arctic-Boreal Vulnerability Experiment
The Arctic-Boreal Vulnerability Experiment (ABoVE) is a NASA Terrestrial Ecology Program field campaign based in Alaska and western Canada between 2016 and 2021. Research for ABoVE links field-based, process-level studies with geospatial data products derived from airborne and satellite sensors, providing a foundation for improving the analysis and modeling capabilities needed to understand and predict ecosystem responses and societal implications.
Acknowledgements
This project was funded by NASA ABoVE grant number NNX15AT81A.
Data Characteristics
Spatial Coverage: Alaska
ABoVE Reference Locations:
Domain: Core ABoVE
State/territory: Alaska
Grid cells: Ahh1Avv0Bh1Bv4, Ahh1Avv0Bh0Bv5, Ahh0Avv1Bh1Bv5Ahh0, Avv0Bh1Bv5, Ahh1Avv0Bh2Bv3, Ahh0Avv0Bh2Bv3
Spatial resolution: Multiple points
Temporal coverage: 2017-03-19 to 2017-03-22
Temporal resolution: Each site was sampled one or more times.
Study Areas (All latitude and longitude given in decimal degrees)
| Site | Westernmost Longitude | Easternmost Longitude | Northernmost Latitude | Southernmost Latitude |
|
Alaska |
-163.238791 |
-146.909819 |
68.55958 |
61.26996 |
Data file information
There is one data file with this dataset in comma-separated (.csv) format: thaw_depth.csv.
The file contains measurements of thaw depth at 1-m intervals along three 30-m transects at various sites throughout Alaska. Coordinates were recorded for the start and end of every 30 meter transect.
Missing data are recorded as -9999.
Table 1. Variables in the data file thaw_depth.csv
|
Column name |
Units/format |
Description |
|---|---|---|
|
date |
YYYY-MM-DD |
Measurement date |
|
site_name |
|
Name of site where measurements were made |
|
site_code |
|
Abbreviated site name. See Table 3. |
|
site |
|
Site number |
|
latitude |
|
Latitude of the beginning and end of each transect. Values given only for sample_location with values of 0 and 30. Other sample_location values are -9999. |
|
longitude |
Decimal degrees |
Longitude of the beginning and end of each transect. Values given only for sample_location with values of 0 and 30. Other sample_location values are -9999. |
|
transect |
Decimal degrees |
Transect number, 1-3 |
|
sample_location |
|
Measurement location along the transect, 0-30. There are 31 measurements per transect. |
|
thaw_depth |
cm |
Thaw depth measurements |
|
notes |
|
Notes recorded during measurements. When a “rock” was encountered, thaw_depth was set to -9999. Other notes may describe surface features (e.g., tussock, tree well) that may indicate that the recorded value is not representative of the site transect. For 3 measurements, the depth exceeded the length of the probe. |
Table 2. Study site locations
| Site Name | Latitude | Longitude |
|
Hess Creek Unburned |
65.567389 |
-148.925157 |
|
Hess Creek Burned |
65.568762 |
-148.92344 |
|
Nome Creek Unburned – Old |
65.285561 |
-146.560019 |
|
Nome Creek Burned – Old |
65.340087 |
-146.910072 |
|
Eight Mile Lake |
63.880123 |
-149.256008 |
|
Bonanza Creek |
64.695999 |
-148.325677 |
|
I-Minus Low |
68.5593 |
-149.51605 |
|
I-Minus High |
68.557159 |
-149.532908 |
|
YK Delta Unburned |
61.270266 |
-163.241038 |
|
YK Delta Burned |
61.2705 |
-163.2356 |
Application and Derivation
These data are part of a larger study to investigate how the magnitudes, fates, and land-atmosphere exchanges of carbon pools are responding to environmental change, and the biogeochemical mechanisms driving these changes.
Quality Assessment
Not provided.
Data Acquisition, Materials, and Methods
Site Selection
Sites were selected to investigate fire disturbance, to span the range of permafrost regions from continuous to sporadic, and to cover vegetation types from boreal forests, tussock tundra, upland willow/herbaceous scrub, and lowland fen and wet tundra sites across Alaska.
Methods
Three 30-meter transects were established at each of the 10 sites (refer to Table 3). Transects were spaced from 10-30 m apart across a site. Coordinates for the 0-m and 30-m end point locations were recorded. Thaw depth was measured and recorded at 1-meter increments along each transect using a 1.15-m T-shaped thaw depth probe. The ABoVE thaw depth protocol was followed, and thaw depth measurements were taken from the top of the moss layer when present. Measurements were in August 2016, June 2017, and September 2017 for most sites (Table 3).
Table 3. Site descriptions
|
Site name |
2016 Sampling Dates |
2017 Sampling Dates |
Description |
|---|---|---|---|
|
Hess Creek Unburned (HCU) |
August 9 |
June 10, September 10, 15 |
The site is located just off the Dalton Highway between mile 11 and 12 within an unburned boreal black spruce forest. |
|
Hess Creek Burned (HCB) |
August 9 |
June 10, September 15 |
The site is located just off the Dalton Highway between mile 11 and 12 within a burned boreal black spruce forest (1995) |
|
Nome Creek Unburned – Old (NCU_OLD) |
August 10 |
June 13, September 18 |
The site is located within the White Mountain Recreation Area on a south facing slope characterized by willow/herbaceous scrub vegetation |
|
Nome Creek Burned – Old (NCB_OLD) |
August 10 |
June 13 |
The site is located within the White Mountain Recreation Area on a south facing slope characterized by willow/herbaceous scrub vegetation which had been previously burned (2004) |
|
Eight Mile Lake (EML) |
August 11 |
June 9, September 20 |
The site is located off the Stampede Trail in Healy. The area is characterized by moist tundra and sedge/shrub vegetation |
|
Bonanza Creek (BNZ) |
August 23 |
June 6, September 17 |
The site is located near the Bonanza Creek LTER Site within a boreal black spruce stand |
|
I-Minus Low (IMNL) |
August 21 |
June, September 11 |
The site is located approximately 1-km off the Dalton Highway, a few miles south of Toolik Field Station. The station is in a lowland, wet sedge fen area (Riparian). Day of sampling not provided for June 2017. Date set to June 15, 2017. |
|
I-Minus High (IMNH) |
August 21 |
June, September 11 |
The site is located approximately 1-km off the Dalton Highway a few miles south of Toolik Field Station. The station is located on top of a hillside, and is characterized by tussock tundra. Day of sampling not provided for June 2017. Date set to June 15, 2017. |
|
YK Delta Unburned (YKDU) |
NA |
September 24 |
The site is located on the Yukon-Kuskokwim Delta characterized by wet tundra vegetation |
|
YK Delta Burned (YKDB) |
NA |
September 24 |
The site is located on the Yukon-Kuskokwim Delta characterized by wet tundra vegetation. The area has been previously burned (2015) |
Data Access
These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).
ABoVE: Thaw Depth at Selected Unburned and Burned Sites Across Alaska, 2016-2017
Contact for Data Center Access Information:
- E-mail: uso@daac.ornl.gov
- Telephone: +1 (865) 241-3952