Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra
Exchanges of methane and carbon dioxide between the atmosphere and the Arctic tundra were measured continuously near Bethel, Alaska (61°05.41'N 162°00.92'W), for 5 weeks during July and August 1988. Fluxes were obtained directly using eddy correlation at 12-m altitude, and concentrations w...
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ftharvardudash:oai:dash.harvard.edu:1/14118807 2023-05-15T15:06:51+02:00 Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra Fan, S. M. Wofsy, Steven Charles Bakwin, P. S. Jacob, Daniel James Anderson, S. M. Kebabian, P. L. McManus, J. B. Kolb, C. E. Fitzjarrald, D. R. 1992 application/pdf http://nrs.harvard.edu/urn-3:HUL.InstRepos:14118807 https://doi.org/10.1029/91JD02531 en_US eng Wiley-Blackwell doi:10.1029/91JD02531 J. Geophys. Res. Fan, S. M., S. C. Wofsy, P. S. Bakwin, D. J. Jacob, S. M. Anderson, P. L. Kebabian, J. B. McManus, C. E. Kolb, and D. R. Fitzjarrald. 1992. “ Micrometeorological Measurements of CH 4 and CO 2 Exchange Between the Atmosphere and Subarctic Tundra .” Journal of Geophysical Research 97 (D15): 16627. doi:10.1029/91jd02531. 0148-0227 http://nrs.harvard.edu/urn-3:HUL.InstRepos:14118807 Journal Article 1992 ftharvardudash https://doi.org/10.1029/91JD02531 https://doi.org/10.1029/91jd02531 2022-04-05T06:46:44Z Exchanges of methane and carbon dioxide between the atmosphere and the Arctic tundra were measured continuously near Bethel, Alaska (61°05.41'N 162°00.92'W), for 5 weeks during July and August 1988. Fluxes were obtained directly using eddy correlation at 12-m altitude, and concentrations were measured sequentially at eight altitudes between 0 and 12 m. A prototype differential infrared absorption methane instrument based on a Zeeman-split HeNe laser was used for determination of methane and a flame ionization detector for total hydrocarbons (THC). Methane was found to account for nearly all the THC concentrations and fluxes. Methane fluxes at the tower site were apportioned to various methane-producing habitats, using a satellite image to classify surface vegetation at 20 × 20 m resolution. The “footprint” of the tower was computed using a Gaussian plume model for dispersion in the surface layer. Grid cells classified as dry tundra (water level 5 cm below surface) emitted methane at an average rate of 11±3 (standard error) mgCH4/m2/d, and wet meadow tundra (water level near surface) emitted 29±3 mgCH4/m2/d. Fluxes from lakes depended on wind speed, averaging 57±6 mgCH4/m2/d at the site, where the mean wind speed was 5ms−1. The mean emission rate for tundra (including lakes) around the tower was 25±1 mgCH4/m2/d, notably smaller than adopted for boreal wetlands in recent inventories of global methane sources. Emissions from major habitats derived from the tower measurements were in reasonable agreement with data from chamber studies. Errors of a factor of ∼2 accrued in scaling up the chamber data, representing 1 m2 plots, to the footprint of the tower measurements (103 m), because the satellite could not fully resolve heterogeneous methane-producing habitats. Fluxes obtained at the tower site were in harmony with fluxes from aircraft overflights. The aircraft data represent mainly afternoon periods with good flying weather, conditions associated with maximum CH4 fluxes in the tower time series. Mean fluxes from the aircraft are consequently ∼2 × higher than seasonal means from the region. Solar irradiance provided the primary control on the net ecosystem exchange (NEE) of carbon dioxide. The mean maximum uptake near the local solar noon was 1.4±0.2 gC/m2/d, and nocturnal respiration averaged 0.73±0.18 gC/m2/d. Net uptake of carbon dioxide averaged 0.30 gC/m2/d (0.1 tons C/hectare) during the period of the Arctic Boundary Layer Experiment (ABLE 3A). About 6% of the seasonal net uptake was returned to the atmosphere as methane. Engineering and Applied Sciences Version of Record Article in Journal/Newspaper Arctic Subarctic Tundra Alaska Harvard University: DASH - Digital Access to Scholarship at Harvard Arctic Journal of Geophysical Research 97 D15 16627 |
institution |
Open Polar |
collection |
Harvard University: DASH - Digital Access to Scholarship at Harvard |
op_collection_id |
ftharvardudash |
language |
English |
description |
Exchanges of methane and carbon dioxide between the atmosphere and the Arctic tundra were measured continuously near Bethel, Alaska (61°05.41'N 162°00.92'W), for 5 weeks during July and August 1988. Fluxes were obtained directly using eddy correlation at 12-m altitude, and concentrations were measured sequentially at eight altitudes between 0 and 12 m. A prototype differential infrared absorption methane instrument based on a Zeeman-split HeNe laser was used for determination of methane and a flame ionization detector for total hydrocarbons (THC). Methane was found to account for nearly all the THC concentrations and fluxes. Methane fluxes at the tower site were apportioned to various methane-producing habitats, using a satellite image to classify surface vegetation at 20 × 20 m resolution. The “footprint” of the tower was computed using a Gaussian plume model for dispersion in the surface layer. Grid cells classified as dry tundra (water level 5 cm below surface) emitted methane at an average rate of 11±3 (standard error) mgCH4/m2/d, and wet meadow tundra (water level near surface) emitted 29±3 mgCH4/m2/d. Fluxes from lakes depended on wind speed, averaging 57±6 mgCH4/m2/d at the site, where the mean wind speed was 5ms−1. The mean emission rate for tundra (including lakes) around the tower was 25±1 mgCH4/m2/d, notably smaller than adopted for boreal wetlands in recent inventories of global methane sources. Emissions from major habitats derived from the tower measurements were in reasonable agreement with data from chamber studies. Errors of a factor of ∼2 accrued in scaling up the chamber data, representing 1 m2 plots, to the footprint of the tower measurements (103 m), because the satellite could not fully resolve heterogeneous methane-producing habitats. Fluxes obtained at the tower site were in harmony with fluxes from aircraft overflights. The aircraft data represent mainly afternoon periods with good flying weather, conditions associated with maximum CH4 fluxes in the tower time series. Mean fluxes from the aircraft are consequently ∼2 × higher than seasonal means from the region. Solar irradiance provided the primary control on the net ecosystem exchange (NEE) of carbon dioxide. The mean maximum uptake near the local solar noon was 1.4±0.2 gC/m2/d, and nocturnal respiration averaged 0.73±0.18 gC/m2/d. Net uptake of carbon dioxide averaged 0.30 gC/m2/d (0.1 tons C/hectare) during the period of the Arctic Boundary Layer Experiment (ABLE 3A). About 6% of the seasonal net uptake was returned to the atmosphere as methane. Engineering and Applied Sciences Version of Record |
format |
Article in Journal/Newspaper |
author |
Fan, S. M. Wofsy, Steven Charles Bakwin, P. S. Jacob, Daniel James Anderson, S. M. Kebabian, P. L. McManus, J. B. Kolb, C. E. Fitzjarrald, D. R. |
spellingShingle |
Fan, S. M. Wofsy, Steven Charles Bakwin, P. S. Jacob, Daniel James Anderson, S. M. Kebabian, P. L. McManus, J. B. Kolb, C. E. Fitzjarrald, D. R. Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra |
author_facet |
Fan, S. M. Wofsy, Steven Charles Bakwin, P. S. Jacob, Daniel James Anderson, S. M. Kebabian, P. L. McManus, J. B. Kolb, C. E. Fitzjarrald, D. R. |
author_sort |
Fan, S. M. |
title |
Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra |
title_short |
Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra |
title_full |
Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra |
title_fullStr |
Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra |
title_full_unstemmed |
Micrometeorological measurements of CH 4 and CO 2 exchange between the atmosphere and subarctic tundra |
title_sort |
micrometeorological measurements of ch 4 and co 2 exchange between the atmosphere and subarctic tundra |
publisher |
Wiley-Blackwell |
publishDate |
1992 |
url |
http://nrs.harvard.edu/urn-3:HUL.InstRepos:14118807 https://doi.org/10.1029/91JD02531 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Subarctic Tundra Alaska |
genre_facet |
Arctic Subarctic Tundra Alaska |
op_relation |
doi:10.1029/91JD02531 J. Geophys. Res. Fan, S. M., S. C. Wofsy, P. S. Bakwin, D. J. Jacob, S. M. Anderson, P. L. Kebabian, J. B. McManus, C. E. Kolb, and D. R. Fitzjarrald. 1992. “ Micrometeorological Measurements of CH 4 and CO 2 Exchange Between the Atmosphere and Subarctic Tundra .” Journal of Geophysical Research 97 (D15): 16627. doi:10.1029/91jd02531. 0148-0227 http://nrs.harvard.edu/urn-3:HUL.InstRepos:14118807 |
op_doi |
https://doi.org/10.1029/91JD02531 https://doi.org/10.1029/91jd02531 |
container_title |
Journal of Geophysical Research |
container_volume |
97 |
container_issue |
D15 |
container_start_page |
16627 |
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1766338413715259392 |