scholarly journals A New Open‐Path Eddy Covariance Method for Nitrous Oxide and Other Trace Gases that Minimizes Temperature Corrections

2021 ◽  
Author(s):  
Da Pan ◽  
Ilya Gelfand ◽  
Lei Tao ◽  
Michael Abraha ◽  
Kang Sun ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Eddy Covariance ◽  
Trace Gases ◽  
Eddy Covariance Method ◽  
Open Path

scholarly journals Dried, closed-path eddy covariance method for measuring carbon dioxide flux over sea ice

2018 ◽  
Vol 11 (11) ◽  
pp. 6075-6090 ◽  
Author(s):  
Brian J. Butterworth ◽  
Brent G. T. Else
Keyword(s):  
Carbon Dioxide ◽  
Sea Ice ◽  
Eddy Covariance ◽  
Co2 Flux ◽  
Carbon Dioxide Flux ◽  
The Arctic ◽  
Closed Path ◽  
Eddy Covariance Method ◽  
Open Path ◽  
Flux Measurements

Abstract. The Arctic marine environment plays an important role in the global carbon cycle. However, there remain large uncertainties in how sea ice affects air–sea fluxes of carbon dioxide (CO2), partially due to disagreement between the two main methods (enclosure and eddy covariance) for measuring CO2 flux (FCO2). The enclosure method has appeared to produce more credible FCO2 than eddy covariance (EC), but is not suited for collecting long-term, ecosystem-scale flux datasets in such remote regions. Here we describe the design and performance of an EC system to measure FCO2 over landfast sea ice that addresses the shortcomings of previous EC systems. The system was installed on a 10 m tower on Qikirtaarjuk Island – a small rock outcrop in Dease Strait located roughly 35 km west of Cambridge Bay, Nunavut, in the Canadian Arctic Archipelago. The system incorporates recent developments in the field of air–sea gas exchange by measuring atmospheric CO2 using a closed-path infrared gas analyzer (IRGA) with a dried sample airstream, thus avoiding the known water vapor issues associated with using open-path IRGAs in low-flux environments. A description of the methods and the results from 4 months of continuous flux measurements from May through August 2017 are presented, highlighting the winter to summer transition from ice cover to open water. We show that the dried, closed-path EC system greatly reduces the magnitude of measured FCO2 compared to simultaneous open-path EC measurements, and for the first time reconciles EC and enclosure flux measurements over sea ice. This novel EC installation is capable of operating year-round on solar and wind power, and therefore promises to deliver new insights into the magnitude of CO2 fluxes and their driving processes through the annual sea ice cycle.

Measuring methane flux from irrigated rice fields by eddy covariance method using open-path gas analyzer

2014 ◽  
Vol 160 ◽  
pp. 12-21 ◽  
Author(s):  
Ma. Carmelita R. Alberto ◽  
Reiner Wassmann ◽  
Roland J. Buresh ◽  
James R. Quilty ◽  
Teodoro Q. Correa ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Methane Flux ◽  
Rice Fields ◽  
Gas Analyzer ◽  
Eddy Covariance Method ◽  
Irrigated Rice ◽  
Open Path

scholarly journals Dried, closed-path eddy covariance method for measuring carbon dioxide flux over sea ice

2018 ◽  
Author(s):  
Brian J. Butterworth ◽  
Brent G. T. Else
Keyword(s):  
Carbon Dioxide ◽  
Sea Ice ◽  
Eddy Covariance ◽  
Co2 Flux ◽  
Carbon Dioxide Flux ◽  
The Arctic ◽  
Closed Path ◽  
Eddy Covariance Method ◽  
Open Path ◽  
Flux Measurements

Abstract. The Arctic marine environment plays an important role in the global carbon cycle. However, there remain large uncertainties in how sea ice affects air–sea fluxes of carbon dioxide (CO2), partially due to disagreement between the two main methods (enclosure and eddy covariance) for measuring CO2 flux (FCO2). The enclosure method has appeared to produce more credible FCO2 than eddy covariance (EC), but is not suited for collecting long-term, ecosystem-scale flux datasets in such remote regions. Here we describe the design and performance of an EC system to measure FCO2 over landfast sea ice that addresses the shortcomings of previous EC systems. The system was installed on a 10-m tower on Qikirtaarjuk Island – a small rock outcrop in Dease Strait located roughly 35 km west of Cambridge Bay, Nunavut in the Canadian Arctic Archipelago. The system incorporates recent developments in the field of air–sea gas exchange by measuring atmospheric CO2 using a closed-path infrared gas analyzer (IRGA) with a dried sample airstream, thus avoiding the known water vapor issues associated with using open-path IRGAs in low-flux environments. A description of the methods and the results from four months of continuous flux measurements from May through August 2017 are presented, highlighting the winter to summer transition from ice cover to open water. We show that the dried, closed-path EC system greatly reduces the magnitude of measured FCO2 compared to simultaneous open-path EC measurements, and for the first time reconciles EC and enclosure flux measurements over sea ice. This novel EC installation is capable of operating year-round on solar/wind power, and therefore promises to deliver new insights into the magnitude of CO2 fluxes and their driving processes through the annual sea ice cycle.

scholarly journals Random Sampling Errors in CO2 Fluxes Measured by the Open-path Eddy Covariance Method and Their Influence on Estimating Annual Carbon Budget

2007 ◽  
Vol 63 (2) ◽  
pp. 67-79 ◽  
Author(s):  
Masayoshi MANO ◽  
Akira MIYATA ◽  
Hideyuki NAGAI ◽  
Tomoyasu YAMADA ◽  
Keisuke ONO ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Random Sampling ◽  
Carbon Budget ◽  
Co2 Fluxes ◽  
Sampling Errors ◽  
Eddy Covariance Method ◽  
Open Path ◽  
Annual Carbon

scholarly journals Standardisation of eddy-covariance flux measurements of methane and nitrous oxide

2018 ◽  
Vol 32 (4) ◽  
pp. 517-549 ◽  
Author(s):  
Eiko Nemitz ◽  
Ivan Mammarella ◽  
Andreas Ibrom ◽  
Mika Aurela ◽  
George G. Burba ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Data Processing ◽  
Eddy Covariance ◽  
Best Practice ◽  
Current Approach ◽  
Observation System ◽  
Gap Filling ◽  
Eddy Covariance Method ◽  
Flux Measurements

Abstract Commercially available fast-response analysers for methane (CH4) and nitrous oxide (N2O) have recently become more sensitive, more robust and easier to operate. This has made their application for long-term flux measurements with the eddy-covariance method more feasible. Unlike for carbon dioxide (CO2) and water vapour (H2O), there have so far been no guidelines on how to optimise and standardise the measurements. This paper reviews the state-of-the-art of the various steps of the measurements and discusses aspects such as instrument selection, setup and maintenance, data processing as well as the additional measurements needed to aid interpretation and gap-filling. It presents the methodological protocol for eddy covariance measurements of CH4 and N2O fluxes as agreed for the ecosystem station network of the pan-European Research Infrastructure Integrated Carbon Observation System and provides a first international standard that is suggested to be adopted more widely. Fluxes can be episodic and the processes controlling the fluxes are complex, preventing simple mechanistic gap-filling strategies. Fluxes are often near or below the detection limit, requiring additional care during data processing. The protocol sets out the best practice for these conditions to avoid biasing the results and long-term budgets. It summarises the current approach to gap-filling.

scholarly journals Permafrost nitrous oxide emissions observed on a landscape scale using the airborne eddy-covariance method

2019 ◽  
Vol 19 (7) ◽  
pp. 4257-4268 ◽  
Author(s):  
Jordan Wilkerson ◽  
Ronald Dobosy ◽  
David S. Sayres ◽  
Claire Healy ◽  
Edward Dumas ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Eddy Covariance ◽  
Tropical Soils ◽  
Nitrous Oxide Emissions ◽  
Eddy Covariance Method ◽  
Large Variability ◽  
Small Areas ◽  
The North ◽  
N2o Fluxes

Abstract. The microbial by-product nitrous oxide (N2O), a potent greenhouse gas and ozone depleting substance, has conventionally been assumed to have minimal emissions in permafrost regions. This assumption has been questioned by recent in situ studies which have demonstrated that some geologic features in permafrost may, in fact, have elevated emissions comparable to those of tropical soils. However, these recent studies, along with every known in situ study focused on permafrost N2O fluxes, have used chambers to examine small areas (<50 m2). In late August 2013, we used the airborne eddy-covariance technique to make in situ N2O flux measurements over the North Slope of Alaska from a low-flying aircraft spanning a much larger area: around 310 km2. We observed large variability of N2O fluxes with many areas exhibiting negligible emissions. Still, the daily mean averaged over our flight campaign was 3.8 (2.2–4.7) mg N2O m−2 d−1 with the 90 % confidence interval shown in parentheses. If these measurements are representative of the whole month, then the permafrost areas we observed emitted a total of around 0.04–0.09 g m−2 for August, which is comparable to what is typically assumed to be the upper limit of yearly emissions for these regions.

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