Air-sea carbon-dioxide flux estimated by eddy covariance method from a buoy observation

Huang, Yongshun; Song, Jinbao; Wang, Juanjuan; Fan, Conghui

doi:10.1007/s13131-012-0253-5

Cited by 9 publications

(7 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Prytherch et al (2010a) went further and presented a correction method (called the Peter K. Taylor -PKT -method), which has since been used in several publications to correct OP CO 2 fluxes (e.g. Prytherch et al, 2010b;Lauvset et al, 2011;Edson et al, 2011;Huang et al, 2012;Ikawa et al, 2013). Huang et al (2012) reported that the PKT correction did bring some of their CO 2 flux measurements closer to the bulk flux estimate, but found that for small water vapour fluxes the PKT method overcorrected the CO 2 flux and, in some cases, even resulted is a reversal of the flux direction.…”

Section: S Landwehr Et Al: Analysis Of the Pkt Correctionmentioning

confidence: 99%

“…Prytherch et al, 2010b;Lauvset et al, 2011;Edson et al, 2011;Huang et al, 2012;Ikawa et al, 2013). Huang et al (2012) reported that the PKT correction did bring some of their CO 2 flux measurements closer to the bulk flux estimate, but found that for small water vapour fluxes the PKT method overcorrected the CO 2 flux and, in some cases, even resulted is a reversal of the flux direction. Ikawa et al (2013) reported that the PKT correction resulted in increased scatter when applied to coastal tower-based CO 2 flux measurements, and decided not to apply the correction.…”

Section: S Landwehr Et Al: Analysis Of the Pkt Correctionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of the PKT correction for direct CO2 flux measurements over the ocean

et al. 2014

View full text Add to dashboard Cite

Abstract. Eddy covariance measurements of air-sea CO 2 fluxes can be affected by cross-sensitivities of the CO 2 measurement to water vapour, resulting in order-of-magnitude biases. Well-established causes for these biases are (i) crosssensitivity of the broadband non-dispersive infrared sensors due to band-broadening and spectral overlap (commercial sensors typically correct for this) and (ii) the effect of air density fluctuations (removed by determining the dry air CO 2 mixing ratio). Another bias related to water vapour fluctuations has recently been observed with open-path sensors, attributed to sea salt build-up and water films on sensor optics. Two very different approaches have been used to deal with these water vapour-related biases. Miller et al. (2010) employed a membrane drier to physically eliminate 97 % of the water vapour fluctuations in the sample air before it entered a closed-path gas analyser. Prytherch et al. (2010a) employed the empirical (Peter K. Taylor, PKT) post-processing correction to correct open-path sensor data. In this paper, we test these methods side by side using data from the Surface Ocean Aerosol Production (SOAP) experiment in the Southern Ocean. The air-sea CO 2 flux was directly measured with four closed-path analysers, two of which were positioned down-stream of a membrane dryer. The CO 2 fluxes from the two dried gas analysers matched each other and were in general agreement with common parameterisations. The flux estimates from the un-dried sensors agreed with the dried sensors only during periods with low latent heat flux (≤ 7 W m −2 ). When latent heat flux was higher, CO 2 flux estimates from the un-dried sensors exhibited large scatter and an order-of-magnitude bias. Applying the PKT correction to the flux data from the un-dried analysers did not remove the bias when compared to the data from the dried gas analyser. The results of this study demonstrate the validity of measuring CO 2 fluxes using a pre-dried air stream and show that the PKT correction is not valid for the correction of CO 2 fluxes.

show abstract

Section: S Landwehr Et Al: Analysis Of the Pkt Correctionmentioning

confidence: 99%

Section: S Landwehr Et Al: Analysis Of the Pkt Correctionmentioning

confidence: 99%

Analysis of the PKT correction for direct CO2 flux measurements over the ocean

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Webb et al, 1980;Fuehrer and Friehe, 2002). Eddy-covariance systems have been installed on research vessels, buoys, and platforms to measure the near-surface CO 2 fluxes above the oceans, mostly on a short timescale of a few weeks (e.g., Huang et al, 2012;Else et al, 2011;Prytherch et al, 2010a, b;Weiss et al, 2007;Kondo and Tsukamoto, 2007). This lower layer of the atmosphere, the Prandl layer, is approximated by a heightconstant turbulent flux.…”

Section: Introductionmentioning

confidence: 99%

CO2-flux measurements above the Baltic Sea at two heights: flux gradients in the surface layer?

Lammert

Ament

2015

Earth Syst. Sci. Data

View full text Add to dashboard Cite

Abstract. The estimation of CO 2 exchange between the ocean and the atmosphere is essential to understand the global carbon cycle. The eddy-covariance technique offers a very direct approach to observe these fluxes. The turbulent CO 2 flux is measured, as well as the sensible and latent heat flux and the momentum flux, a few meters above the ocean in the atmosphere. Assuming a constant-flux layer in the near-surface part of the atmospheric boundary layer, this flux equals the exchange flux between ocean and atmosphere. The purpose of this paper is the comparison of long-term flux measurements at two different heights above the Baltic Sea to investigate this assumption. The results are based on a 1.5-year record of quality-controlled eddy-covariance measurements. Concerning the flux of momentum and of sensible and latent heat, the constant-flux layer theory can be confirmed because flux differences between the two heights are insignificantly small more than 95 % of the time. In contrast, significant differences, which are larger than the measurement error, occur in the CO 2 flux about 35 % of the time. Data used for this paper are published at http://doi.pangaea.de/10.1594/PANGAEA.808714.

show abstract

Section: Introductionmentioning

confidence: 99%

Analysis of the PKT correction for direct CO2 flux measurements over the ocean

Landwehr¹,

Miller²,

Smith³

et al. 2013

Preprint

View full text Add to dashboard Cite

Eddy covariance measurements of air–sea CO₂ fluxes can be affected by cross-sensitivities of the CO₂ measurement to water vapour, resulting in order-of-magnitude biases. Well established causes for these biases are (i) cross-sensitivity of the broadband non-dispersive infrared sensors due to band-broadening and spectral overlap (commercial sensors typically correct for this) and (ii) the effect of air density fluctuations (removed by determining the CO₂ mixing ratio respective to dry air). However, another bias related to water vapour fluctuations has recently been observed with open-path sensors, and was attributed to sea salt build-up and water films on sensor optics. Two very different approaches have been used to deal with these water vapour-related biases. Miller et al. (2010) employed a membrane drier to physically eliminate 97% of the water vapour fluctuations in the sample air before it enters the gas analyser. Prytherch et al. (2010a) on the other hand, employed the empirical (Peter K. Taylor, PKT) post-processing correction to correct open-path sensor data. In this paper, we test these methods side by side using data from the Surface Ocean Aerosol Production (SOAP) experiment in the Southern Ocean. The air–sea CO₂ flux was directly measured with four closed-path analysers, two of which were positioned down-stream of a membrane dryer. The CO₂ fluxes from the two dried gas analysers matched each other and were in general agreement with common parametrisations. The flux estimates from the un-dried sensors agreed with the dried sensors only during periods with low latent heat flux (≤ 7 W m⁻²). When latent heat flux was higher, CO₂ flux estimates from the un-dried sensors exhibited large scatter and an order-of magnitude bias. We applied the PKT correction to the flux data from the un-dried analysers and found that it did not remove the bias when compared to the data from the dried gas analyser. Our detailed analysis of the correction algorithm reveals that this method is not valid for the correction of CO₂ fluxes

show abstract

Air-sea carbon-dioxide flux estimated by eddy covariance method from a buoy observation

Cited by 9 publications

References 15 publications

Analysis of the PKT correction for direct CO<sub>2</sub> flux measurements over the ocean

Analysis of the PKT correction for direct CO<sub>2</sub> flux measurements over the ocean

CO<sub>2</sub>-flux measurements above the Baltic Sea at two heights: flux gradients in the surface layer?

Analysis of the PKT correction for direct CO<sub>2</sub> flux measurements over the ocean

Contact Info

Product

Resources

About

Air-sea carbon-dioxide flux estimated by eddy covariance method from a buoy observation

Cited by 9 publications

References 15 publications

Analysis of the PKT correction for direct CO&lt;sub&gt;2&lt;/sub&gt; flux measurements over the ocean

Analysis of the PKT correction for direct CO&lt;sub&gt;2&lt;/sub&gt; flux measurements over the ocean

CO&lt;sub&gt;2&lt;/sub&gt;-flux measurements above the Baltic Sea at two heights: flux gradients in the surface layer?

Analysis of the PKT correction for direct CO&lt;sub&gt;2&lt;/sub&gt; flux measurements over the ocean

Contact Info

Product

Resources

About

Analysis of the PKT correction for direct CO<sub>2</sub> flux measurements over the ocean

Analysis of the PKT correction for direct CO<sub>2</sub> flux measurements over the ocean

CO<sub>2</sub>-flux measurements above the Baltic Sea at two heights: flux gradients in the surface layer?

Analysis of the PKT correction for direct CO<sub>2</sub> flux measurements over the ocean