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Model-data fusion to assess year-round CO2 fluxes for an arctic heath ecosystem in West Greenland (69°N)

Zhang, Wenxin LU orcid ; Jansson, Per-Erik ; Sigsgaard, Charlotte ; McConnell, Alistair ; Jammet, Mathilde ; Westergaard-Nielsen, Andreas ; Lund, Magnus ; Friborg, Thomas ; Michelsen, Anders and Elberling, Bo (2019) In Agricultural and Forest Meteorology 272-273. p.176-186
Abstract
Quantifying net CO2 exchange (NEE) of arctic terrestrial ecosystems in response to changes in climatic and environmental conditions is central to understanding ecosystem functioning and assessing potential feedbacks of the carbon cycle to future climate changes. However, annual CO2 budgets for arctic tundra are rare due to the difficulties of performing measurements during non-growing seasons. It is still unclear to what extent arctic tundra ecosystems currently act as a CO2 source, sink or are in balance. This study presents year-round eddy-covariance (EC) measurements of CO2 fluxes for an arctic heath ecosystem on Disko Island, West Greenland (69 °N) over five years. Based on a fusion of year-round EC-derived CO2 fluxes, soil temperature... (More)
Quantifying net CO2 exchange (NEE) of arctic terrestrial ecosystems in response to changes in climatic and environmental conditions is central to understanding ecosystem functioning and assessing potential feedbacks of the carbon cycle to future climate changes. However, annual CO2 budgets for arctic tundra are rare due to the difficulties of performing measurements during non-growing seasons. It is still unclear to what extent arctic tundra ecosystems currently act as a CO2 source, sink or are in balance. This study presents year-round eddy-covariance (EC) measurements of CO2 fluxes for an arctic heath ecosystem on Disko Island, West Greenland (69 °N) over five years. Based on a fusion of year-round EC-derived CO2 fluxes, soil temperature and moisture, the process-oriented model (CoupModel) has been constrained to quantify an annual budget and characterize seasonal patterns of CO2 fluxes. The results show that total photosynthesis corresponds to -202 ± 20 g C m−2 yr-1 with ecosystem respiration of 167 ± 28 g C m-2 yr-1, resulting in NEE of -35 ± 15 g C m-2 yr-1. The respiration loss is mainly described as decomposition of near-surface litter. A year with an anomalously deep snowpack shows a threefold increase in the rate of ecosystem respiration compared to other years. Due to the high CO2 emissions during that winter, the annual budget results in a marked reduction in the CO2 sink. The seasonal patterns of photosynthesis and soil respiration were described using response functions of the forcing atmosphere and soil conditions. Snow depth, topography-related soil moisture, and growing season warmth are identified as important environmental characteristics which most influence seasonal rates of gas exchange. (Less)
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author
; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Agricultural and Forest Meteorology
volume
272-273
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:85064630872
ISSN
1873-2240
DOI
10.1016/j.agrformet.2019.02.021
language
English
LU publication?
yes
id
47f2eb00-9e4e-47cc-bf86-7d5640d5a5dc
date added to LUP
2019-05-03 17:02:49
date last changed
2023-04-29 04:10:45
@article{47f2eb00-9e4e-47cc-bf86-7d5640d5a5dc,
  abstract     = {{Quantifying net CO2 exchange (NEE) of arctic terrestrial ecosystems in response to changes in climatic and environmental conditions is central to understanding ecosystem functioning and assessing potential feedbacks of the carbon cycle to future climate changes. However, annual CO2 budgets for arctic tundra are rare due to the difficulties of performing measurements during non-growing seasons. It is still unclear to what extent arctic tundra ecosystems currently act as a CO2 source, sink or are in balance. This study presents year-round eddy-covariance (EC) measurements of CO2 fluxes for an arctic heath ecosystem on Disko Island, West Greenland (69 °N) over five years. Based on a fusion of year-round EC-derived CO2 fluxes, soil temperature and moisture, the process-oriented model (CoupModel) has been constrained to quantify an annual budget and characterize seasonal patterns of CO2 fluxes. The results show that total photosynthesis corresponds to -202 ± 20 g C m−2 yr-1 with ecosystem respiration of 167 ± 28 g C m-2 yr-1, resulting in NEE of -35 ± 15 g C m-2 yr-1. The respiration loss is mainly described as decomposition of near-surface litter. A year with an anomalously deep snowpack shows a threefold increase in the rate of ecosystem respiration compared to other years. Due to the high CO2 emissions during that winter, the annual budget results in a marked reduction in the CO2 sink. The seasonal patterns of photosynthesis and soil respiration were described using response functions of the forcing atmosphere and soil conditions. Snow depth, topography-related soil moisture, and growing season warmth are identified as important environmental characteristics which most influence seasonal rates of gas exchange.}},
  author       = {{Zhang, Wenxin and Jansson, Per-Erik and Sigsgaard, Charlotte and McConnell, Alistair and Jammet, Mathilde and Westergaard-Nielsen, Andreas and Lund, Magnus and Friborg, Thomas and Michelsen, Anders and Elberling, Bo}},
  issn         = {{1873-2240}},
  language     = {{eng}},
  month        = {{04}},
  pages        = {{176--186}},
  publisher    = {{Elsevier}},
  series       = {{Agricultural and Forest Meteorology}},
  title        = {{Model-data fusion to assess year-round CO2 fluxes for an arctic heath ecosystem in West Greenland (69°N)}},
  url          = {{http://dx.doi.org/10.1016/j.agrformet.2019.02.021}},
  doi          = {{10.1016/j.agrformet.2019.02.021}},
  volume       = {{272-273}},
  year         = {{2019}},
}