Nonlinear controls on evapotranspiration in arctic coastal wetlands
Abstract: Projected increases in air temperature and precipitation due to climate change in Arctic wetlands could dramatically affect ecosystem function. As a consequence, it is important to define controls on evapotranspiration, the major pathway of water loss from these systems. We quantified the...
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ftunivantwerpen:c:irua:97259 2023-07-16T03:56:32+02:00 Nonlinear controls on evapotranspiration in arctic coastal wetlands Liljedahl, A.K. Hinzman, L.D. Harazono, Y. Zona, Donatella Tweedie, C.E. Hollister, R.D. Engstrom, R. Oechel, W.C. 2011 pdf https://hdl.handle.net/10067/972590151162165141 https://repository.uantwerpen.be/docman/irua/171496/1521.pdf eng eng info:eu-repo/semantics/altIdentifier/doi/10.5194/BG-8-3375-2011 info:eu-repo/semantics/altIdentifier/isi/000298132200018 info:eu-repo/semantics/openAccess 1726-4170 Biogeosciences Physics Chemistry Biology info:eu-repo/semantics/article 2011 ftunivantwerpen https://doi.org/10.5194/BG-8-3375-2011 2023-06-26T22:15:47Z Abstract: Projected increases in air temperature and precipitation due to climate change in Arctic wetlands could dramatically affect ecosystem function. As a consequence, it is important to define controls on evapotranspiration, the major pathway of water loss from these systems. We quantified the multi-year controls on midday Arctic coastal wetland evapotranspiration, measured with the eddy covariance method at two vegetated, drained thaw lake basins near Barrow, Alaska. Variations in near-surface soil moisture and atmospheric vapor pressure deficits were found to have nonlinear effects on midday evapotranspiration rates. Vapor pressure deficits (VPD) near 0.3 kPa appeared to be an important hydrological threshold, allowing latent heat flux to persistently exceed sensible heat flux. Dry (compared to wet) soils increased bulk surface resistance (water-limited). Wet soils favored ground heat flux and therefore limited the energy available to sensible and latent heat flux (energy-limited). Thus, midday evapotranspiration was suppressed from both dry and wet soils but through different mechanisms. We also found that wet soils (ponding excluded) combined with large VPD, resulted in an increased bulk surface resistance and therefore suppressing evapotranspiration below its potential rate (Priestley-Taylor alpha < 1.26). This was likely caused by the limited ability of mosses to transfer moisture during large atmospheric demands. Ultimately, in addition to net radiation, the various controlling factors on midday evapotranspiration (i.e., near-surface soil moisture, atmospheric vapor pressure, and the limited ability of saturated mosses to transfer water during high VPD) resulted in an average evapotranspiration rate of up to 75% of the potential evapotranspiration rate. These multiple limitations on midday evapotranspiration rates have the potential to moderate interannual variation of total evapotranspiration and reduce excessive water loss in a warmer climate. Combined with the prevailing maritime winds and ... Article in Journal/Newspaper Arctic Barrow Climate change Alaska IRUA - Institutional Repository van de Universiteit Antwerpen Arctic Priestley ENVELOPE(161.883,161.883,-75.183,-75.183) Biogeosciences 8 11 3375 3389 |
institution |
Open Polar |
collection |
IRUA - Institutional Repository van de Universiteit Antwerpen |
op_collection_id |
ftunivantwerpen |
language |
English |
topic |
Physics Chemistry Biology |
spellingShingle |
Physics Chemistry Biology Liljedahl, A.K. Hinzman, L.D. Harazono, Y. Zona, Donatella Tweedie, C.E. Hollister, R.D. Engstrom, R. Oechel, W.C. Nonlinear controls on evapotranspiration in arctic coastal wetlands |
topic_facet |
Physics Chemistry Biology |
description |
Abstract: Projected increases in air temperature and precipitation due to climate change in Arctic wetlands could dramatically affect ecosystem function. As a consequence, it is important to define controls on evapotranspiration, the major pathway of water loss from these systems. We quantified the multi-year controls on midday Arctic coastal wetland evapotranspiration, measured with the eddy covariance method at two vegetated, drained thaw lake basins near Barrow, Alaska. Variations in near-surface soil moisture and atmospheric vapor pressure deficits were found to have nonlinear effects on midday evapotranspiration rates. Vapor pressure deficits (VPD) near 0.3 kPa appeared to be an important hydrological threshold, allowing latent heat flux to persistently exceed sensible heat flux. Dry (compared to wet) soils increased bulk surface resistance (water-limited). Wet soils favored ground heat flux and therefore limited the energy available to sensible and latent heat flux (energy-limited). Thus, midday evapotranspiration was suppressed from both dry and wet soils but through different mechanisms. We also found that wet soils (ponding excluded) combined with large VPD, resulted in an increased bulk surface resistance and therefore suppressing evapotranspiration below its potential rate (Priestley-Taylor alpha < 1.26). This was likely caused by the limited ability of mosses to transfer moisture during large atmospheric demands. Ultimately, in addition to net radiation, the various controlling factors on midday evapotranspiration (i.e., near-surface soil moisture, atmospheric vapor pressure, and the limited ability of saturated mosses to transfer water during high VPD) resulted in an average evapotranspiration rate of up to 75% of the potential evapotranspiration rate. These multiple limitations on midday evapotranspiration rates have the potential to moderate interannual variation of total evapotranspiration and reduce excessive water loss in a warmer climate. Combined with the prevailing maritime winds and ... |
format |
Article in Journal/Newspaper |
author |
Liljedahl, A.K. Hinzman, L.D. Harazono, Y. Zona, Donatella Tweedie, C.E. Hollister, R.D. Engstrom, R. Oechel, W.C. |
author_facet |
Liljedahl, A.K. Hinzman, L.D. Harazono, Y. Zona, Donatella Tweedie, C.E. Hollister, R.D. Engstrom, R. Oechel, W.C. |
author_sort |
Liljedahl, A.K. |
title |
Nonlinear controls on evapotranspiration in arctic coastal wetlands |
title_short |
Nonlinear controls on evapotranspiration in arctic coastal wetlands |
title_full |
Nonlinear controls on evapotranspiration in arctic coastal wetlands |
title_fullStr |
Nonlinear controls on evapotranspiration in arctic coastal wetlands |
title_full_unstemmed |
Nonlinear controls on evapotranspiration in arctic coastal wetlands |
title_sort |
nonlinear controls on evapotranspiration in arctic coastal wetlands |
publishDate |
2011 |
url |
https://hdl.handle.net/10067/972590151162165141 https://repository.uantwerpen.be/docman/irua/171496/1521.pdf |
long_lat |
ENVELOPE(161.883,161.883,-75.183,-75.183) |
geographic |
Arctic Priestley |
geographic_facet |
Arctic Priestley |
genre |
Arctic Barrow Climate change Alaska |
genre_facet |
Arctic Barrow Climate change Alaska |
op_source |
1726-4170 Biogeosciences |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/BG-8-3375-2011 info:eu-repo/semantics/altIdentifier/isi/000298132200018 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/BG-8-3375-2011 |
container_title |
Biogeosciences |
container_volume |
8 |
container_issue |
11 |
container_start_page |
3375 |
op_container_end_page |
3389 |
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1771542931057934336 |