Eddy covariance measurements with a new fast-response, enclosed-path analyzer: Spectral characteristics and cross-system comparisons

Novick, Kim; Walker, John S.; Sc, Chan; Schmidt, A.; Sobek, C.; Vose, James M.

doi:10.1016/j.agrformet.2013.06.020

Cited by 30 publications

(41 citation statements)

References 33 publications

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“…Previous studies have shown large high-frequency flux attenuation of traditional closed-path gas analysers (Haslwanter et al, 2009), such as used in this study at the dry heath site, caused by tube walls and tube age (Su et al, 2004;Massman and Ibrom, 2008) and tube length (Novik et al, 2013). Enclosed-path systems, however, reduce flux attenuation compared to traditional closed-path systems due to shorter tube length (Burba et al, 2010;Novick et al, 2013).…”

Section: Energy Balance Closure and System Performancementioning

confidence: 56%

Section: Study Sitesmentioning

confidence: 99%

“…Mean annual air temperature in Zackenberg (1996Zackenberg ( -2013) is −9.0 • C, with an average span from −19.3 • C in January to +6.3 • C in July (Mylius et al, 2014). Annual precipitation is low (211 mm) (Mylius et al, 2014) and ∼ 85 % consists of snow precipitation . Snow cover is unevenly distributed in the valley with large deposits on southfacing slopes as winds from the north (offshore) dominate during the winter (Soegaard et al, 2001).…”

Section: Study Sitesmentioning

confidence: 99%

“…Our study area is located in Zackenberg in Northeast Greenland, where record-low snow accumulation was observed during the winter 2012/2013 (Mylius et al, 2014) followed by snow-rich conditions during the winter 2013/2014. This sequence of strong variability in snow accumulation forms the following objectives of our study:…”

Section: Introductionmentioning

confidence: 99%

“…Based on the IPCC SRES A1B scenario (Nakićenović et al, 2000), local climate modelling for the region predicts an increase in mean annual air temperature by 4.1 • C for the period 2051-2080 compared to 1961-1990 with the highest increase during winter (6.6 • C) and spring (7.4 • C), while precipitation over eastern Greenland is projected to increase by 60 % (Stendel et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Two years with extreme and little snowfall: effects on energy partitioning and surface energy exchange in a high-Arctic tundra ecosystem

et al. 2016

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Abstract. Snow cover is one of the key factors controlling Arctic ecosystem functioning and productivity. In this study we assess the impact of strong variability in snow accumulation during 2 subsequent years (2013-2014) on the landatmosphere interactions and surface energy exchange in two high-Arctic tundra ecosystems (wet fen and dry heath) in Zackenberg, Northeast Greenland. We observed that recordlow snow cover during the winter 2012/2013 resulted in a strong response of the heath ecosystem towards low evaporative capacity and substantial surface heat loss by sensible heat fluxes (H ) during the subsequent snowmelt period and growing season. Above-average snow accumulation during the winter 2013/2014 promoted summertime ground heat fluxes (G) and latent heat fluxes (LE) at the cost of H . At the fen ecosystem a more muted response of LE, H and G was observed in response to the variability in snow accumulation. Overall, the differences in flux partitioning and in the length of the snowmelt periods and growing seasons during the 2 years had a strong impact on the total accumulation of the surface energy balance components. We suggest that in a changing climate with higher temperature and more precipitation the surface energy balance of this high-Arctic tundra ecosystem may experience a further increase in the variability of energy accumulation, partitioning and redistribution.

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Section: Energy Balance Closure and System Performancementioning

confidence: 56%

Section: Study Sitesmentioning

confidence: 99%

Section: Study Sitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Two years with extreme and little snowfall: effects on energy partitioning and surface energy exchange in a high-Arctic tundra ecosystem

et al. 2016

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Marsh‐atmosphere CO₂ exchange in a New England salt marsh

Forbrich

Giblin

2015

JGR Biogeosciences

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We studied marsh-atmosphere exchange of carbon dioxide in a high marsh dominated salt marsh during the months of May to October in 2012-2014. Tidal inundation at the site occurred only during biweekly spring tides, during which we observed a reduction in fluxes during day and night. We estimated net ecosystem exchange (NEE), gross primary production (GPP), and ecosystem respiration (R eco ) using a modified PLIRTLE model, which requires photosynthetically active radiation, temperature, and normalized difference vegetation index (NDVI) as control variables. NDVI decreased during inundation, when the marsh canopy was submerged. Two-time series of NDVI, including and excluding effects of tidal inundation, allowed us to quantify the flux reduction during inundation. The effect of the flux reduction was small (2-4%) at our site, but is likely higher for marshes at a lower elevation. From May to October, GPP averaged −863 g C m −2 , R eco averaged 591 g C m −2 , and NEE averaged −291 g C m −2 . In 2012, which was an exceptionally warm year, we observed an early start of net carbon uptake but higher respiration than in 2013 and 2014 due to higher-air temperature in August. This resulted in the lowest NEE during the study period (−255.9 ± 6.9 g C m −2 ). The highest seasonal net uptake (−336.5 ± 6.3 g C m −2 ) was observed in 2013, which was linked to higher rainfall and temperature in July. Mean sea level was very similar during all 3 years which allowed us to isolate the importance of climatic factors.

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Constraining Marsh Carbon Budgets Using Long‐Term C Burial and Contemporary Atmospheric CO₂ Fluxes

2018

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Salt marshes are sinks for atmospheric carbon dioxide that respond to environmental changes related to sea level rise and climate. Here we assess how climatic variations affect marsh‐atmosphere exchange of carbon dioxide in the short term and compare it to long‐term burial rates based on radiometric dating. The 5 years of atmospheric measurements show a strong interannual variation in atmospheric carbon exchange, varying from −104 to −233 g C m−2 a−1 with a mean of −179 ± 32 g C m−2 a−1. Variation in these annual sums was best explained by differences in rainfall early in the growing season. In the two years with below average rainfall in June, both net uptake and Normalized Difference Vegetation Index were less than in the other three years. Measurements in 2016 and 2017 suggest that the mechanism behind this variability may be rainfall decreasing soil salinity which has been shown to strongly control productivity. The net ecosystem carbon balance was determined as burial rate from four sediment cores using radiometric dating and was lower than the net uptake measured by eddy covariance (mean: 110 ± 13 g C m−2 a−1). The difference between these estimates was significant and may be because the atmospheric measurements do not capture lateral carbon fluxes due to tidal exchange. Overall, it was smaller than values reported in the literature for lateral fluxes and highlights the importance of investigating lateral C fluxes in future studies.

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Eddy covariance measurements with a new fast-response, enclosed-path analyzer: Spectral characteristics and cross-system comparisons

Cited by 30 publications

References 33 publications

Two years with extreme and little snowfall: effects on energy partitioning and surface energy exchange in a high-Arctic tundra ecosystem

Two years with extreme and little snowfall: effects on energy partitioning and surface energy exchange in a high-Arctic tundra ecosystem

Marsh‐atmosphere CO₂ exchange in a New England salt marsh

Constraining Marsh Carbon Budgets Using Long‐Term C Burial and Contemporary Atmospheric CO₂ Fluxes

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Eddy covariance measurements with a new fast-response, enclosed-path analyzer: Spectral characteristics and cross-system comparisons

Cited by 30 publications

References 33 publications

Two years with extreme and little snowfall: effects on energy partitioning and surface energy exchange in a high-Arctic tundra ecosystem

Two years with extreme and little snowfall: effects on energy partitioning and surface energy exchange in a high-Arctic tundra ecosystem

Marsh‐atmosphere CO2 exchange in a New England salt marsh

Constraining Marsh Carbon Budgets Using Long‐Term C Burial and Contemporary Atmospheric CO2 Fluxes

Contact Info

Product

Resources

About

Marsh‐atmosphere CO₂ exchange in a New England salt marsh

Constraining Marsh Carbon Budgets Using Long‐Term C Burial and Contemporary Atmospheric CO₂ Fluxes