SAR-based Methane Ebullition Flux from Lakes, Five Regions, Alaska, 2007-2010

Melanie J. Engram; Anthony, K.W.; Meyer, F.J.

This dataset provides Synthetic Aperture Radar (SAR) estimates of lake-source methane ebullition flux in mg CH4/m2/d for thousands of lakes in five regions across Alaska. The study regions include the Atqasuk, Barrow Peninsula, Fairbanks, northern Seward Peninsula, and Toolik. L-band SAR backscatter values for early winter lake ice scenes were collected from 2007 to 2010 over 5,143 lakes using the Phased Array type L-band Synthetic Aperture Radar (PALSAR) instrument on the Advanced Land Observing Satellite (ALOS-1) satellite. The backscatter data were combined with field measurements of methane ebullition from 48 study lakes across the five regions to obtain a volumetric flux estimate for each lake. Mean methane gas-fractions from each region were applied to the SAR-based volumetric fluxes to obtain an estimate of methane ebullition mass flux per lake. The data files contain lake perimeters and the lake-specific attributes of lake area, SAR backscatter values and standard errors, volumetric flux with standard errors, mean percent of methane from gas samples, and methane ebullition mass flux.

Citation

In order to use these data, you must cite this data set with the following citation:

Engram, M.J., K.W. Anthony, and F.J. Meyer. 2020. ABoVE: SAR-based Methane Ebullition Flux from Lakes, Five Regions, Alaska, 2007-2010. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1790

This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use Policy.

Contact

ORNL DAAC

Metadata Access

DCAT in RDF/XML-Format

DCAT in Turtle-Format

DCAT in JSON-LD-Format

APGC Dataset Metadata in JSON-Format

Data and Resources

Additional Info

Field Value
Identifier DOI: 10.3334/ORNLDAAC/1790
Project(s) Arctic-Boreal Vulnerability Experiment (ABoVE)
Institute University of Alaska Fairbanks
Source https://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1790
Publication Date 2020-07-15
Version 1.0
Product SAR estimates of lake based methane flux
Sensor Phased Array type L-band Synthetic Aperture Radar (PALSAR) instrument on the Advanced Land Observing Satellite (ALOS-1) satellite
Files
  1. Atqasuk zipped shapfile
  2. Atqasuk kml file
  3. Barrow Peninsula zipped shapefile
  4. Barrow Peninsula kml file
  5. Fairbanks zipped shapfile
  6. Fairbanks kml file
  7. Nothern Seward Peninsula zipped shapfile
  8. Nothern Seward Peninsula kml file
  9. Toolik zipped shapfile
  10. Toolik kml file
Variables [Units]
  1. ID: A lake ID number that is unique within regions.
  2. AreaSqkm: Lake area in square km. Lake area is calculated prior to buffering the shoreline. [km2]
  3. BUFF_DIST: Buffered distance inward from shoreline in meters. [m]
  4. N_scenes: Number of SAR scenes that cover the lake.
  5. SAR_allYrs: Mean SAR backscatter intensity (T11 component) for the lake for all n scenes covering the lake. [powerscale]
  6. SE_SARall: The standard error of SAR_allYrs, calculated as the standard deviation divided by the square root of one-fourth the pixel count. The pixel count was divided by four to account for smoothing that occurred during the speckle-filtering process. [powerscale]
  7. SAR_eFlux: The SAR-based volumetric gas flux, calculated by inverting the empirical regression model, expressed in ml gas m-2d-1. [ml gas m-2d-1]
  8. SE_SAReFlx: The standard error of SAR_eFlux, calculated as the standard deviation divided by the square root of one-fourth the pixel count. The pixel count was divided by four to account for smoothing that occurred during the speckle-filtering process. [ml gas m-2d-1]
  9. Prcnt_CH4: The average methane gas-fraction from gas samples in the region used to convert volumetric flux to mass flux. [%]
  10. MassFlxCH4: The mass flux, calculated with the Prcnt_CH4 value and standard gas laws. [mg CH4 m-2d-1]
  11. Count_YYYY: Pixel count (12.5-m pixels) of processed SAR data for the lake for the year specified YYYY. Years are shown in Table 2.
  12. Mean_YYYY: Mean SAR backscatter intensity (T11 component) for the lake for year YYYY. [powerscale]
  13. SE_YYYY: Standard Error of Mean_YYYY, calculated as the standard deviation divided by the square root of one-fourth the pixel count. The pixel count was divided by four to account for smoothing that occurred during the speckle-filtering process. [powerscale]
Region Alaska, USA
Spatial Reference EPSG:26903-26906 WGS 84 / UTM zone 3-6 N
Spatial Resolution 12.5 m
Spatial Coverage Latitude 64.44 to 71.34, Longitude -147.37 to -165.17
Temporal Coverage 2007-11-13 to 2010-11-11
Temporal Resolution Varied
Format Zipped shapefile, keyhole markup language file
Is Supplement To

Engram, M., K.M. Walter Anthony, T. Sachs, K. Kohnert, A. Serafimovich, G. Grosse, and F.J. Meyer. 2020. Remote sensing northern lake methane ebullition. Nature Climate Change. 10(6):511-517. https://doi.org/10.1038/s41558-020-0762-8
Related to

Greene, S.B., K.M. Walter Anthony, D. Archer, D., A. Sepulveda-Jauregui, and K. Martinez-Cruz. 2014. Modeling the impediment of methane ebullition bubbles by seasonal lake ice. Biogeosciences, 11: 6791–6811. https://doi.org/10.5194/bg-11-6791-2014

Walter Anthony, K.M., T. Schneider von Deimling, I. Nitze, S. Frolking, A. Emond, R. Daanen, P. Anthony, P. Lindgren, B. Jones, and G Grosse. 2010. Estimating methane emissions from northern lakes using ice-bubble surveys. Limnology and Oceanography: Methods, 8: 592–609. https://doi.org/10.4319/lom.2010.8.0592

Dataset extent

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