Evaluating transfer velocity-wind speed relationship using a long-term series of direct eddy correlation CO2 flux measurements

Weiss, Alexandra; Kuss, Joachim; Peters, Gerhard; Schneider, Bernd

doi:10.1016/j.jmarsys.2006.04.011

Cited by 61 publications

(66 citation statements)

References 27 publications

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“…4) compared to the lower (60 %) average ( Hg 0 ml =16.2 ng m −3 ) determined during the several years of the present study. Second, the k parameterization of the gas exchange transfer velocity according to Nightingale et al (2000) vs. that of Weiss et al (2007) similarly resulted in a 60 % lower estimate in our study than in the 2006 study. In addition, the actual wind speed measured in 2006 was higher than the climatological mean, which would account for an additional 20 % reduction in the annual emission rate.…”

Section: Emission Budget Of the Baltic Seacontrasting

confidence: 52%

“…The strongest impact on the results was most likely the differences in the k parameterizations that had been applied. These included the k(u) of Liss and Merlivat (1986) (LM86), Nightingale et al (2000) (Night2000), and Wanninkhof (1992) that was used in the form k 660 = 0.31u 2 or k 660 = 0.39u 2 (WH92) according to the type of wind speed data, as well as a parameterization determined in the Baltic Sea (Weiss et al, 2007), Weiss2007. Since k(u) consists of two parts (Eq.…”

Section: Hg 0 Emission Fluxes Of the Baltic Sea And Other Marginal Seasmentioning

confidence: 99%

“…The method used in data collection is shown as well: quantitative extraction of samples (P&T), equilibrator (Equ), or high-resolution equilibrator (Equ-high) measurements. Actual onboard measured wind speeds were used with the gas exchange model indicated: Night2000 (Nightingale et al, 2000), Weiss2007 (Weiss et al, 2007), WH92 (Wanninkhof, 1992), or other a, b . All fluxes were additionally recalculated to obtain rough estimates of the fluxes according to Night2000 (see text).…”

Section: Emission Budget Of the Baltic Seamentioning

confidence: 99%

“…In addition, the multi-approach of Nightingale et al (2000) describing the transfer velocity-wind speed relationship did gain the acceptance of many scientists in the field of gas exchange. Given the indications of an elevated transfer velocity for the Baltic Sea at higher wind speeds (Kuss et al, 2004;Weiss et al, 2007), in this study we use the parametrization of Nightingale et al (2000).…”

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High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

et al. 2018

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Abstract. Marginal seas are directly subjected to anthropogenic and natural influences from land in addition to receiving inputs from the atmosphere and open ocean. Together these lead to pronounced gradients and strong dynamic changes. However, in the case of mercury emissions from these seas, estimates often fail to adequately account for the spatial and temporal variability of the elemental mercury concentration in surface water (Hg 0 wat ). In this study, a method to measure Hg 0 wat at high resolution was devised and subsequently validated. The better-resolved Hg 0 wat dataset, consisting of about one measurement per nautical mile, yielded insight into the sea's small-scale variability and thus improved the quantification of the sea's Hg 0 emission. This is important because global marine Hg 0 emissions constitute a major source of atmospheric mercury.Research campaigns in the Baltic Sea were carried out between 2011 and 2015 during which Hg 0 both in surface water and in ambient air were measured. For the former, two types of equilibrators were used. A membrane equilibrator enabled continuous equilibration and a bottle equilibrator assured that equilibrium was reached for validation. The measurements were combined with data obtained in the Baltic Sea in 2006 from a bottle equilibrator only. The Hg 0 sea-air flux was newly calculated with the combined dataset based on current knowledge of the Hg 0 Schmidt number, Henry's law constant, and a widely used gas exchange transfer velocity parameterization. By using a newly developed pump-CTD with increased pumping capability in the Hg 0 equilibrator measurements, Hg 0 wat could also be characterized in deeper water layers. A process study carried out near the Swedish island Øland in August 2015 showed that the upwelling of Hg 0 -depleted water contributed to Hg 0 emissions of the Baltic Sea. However, a delay of a few days after contact between the upwelled water and light was apparently necessary before the biotic and abiotic transformations of ionic to volatile Hg 0 produced a distinct sea-air Hg 0 concentration gradient.This study clearly showed spatial, seasonal, and interannual variability in the Hg 0 sea-air flux of the Baltic Sea. The average annual Hg 0 emission was 0.90 ± 0.18 Mg for the Baltic proper and extrapolated to 1.73 ± 0.32 Mg for the entire Baltic Sea, which is about half the amount entrained by atmospheric deposition. A comparison of our results with the Hg 0 sea-air fluxes determined in the Mediterranean Sea and in marginal seas in East Asia were to some extent similar but they partly differed in terms of the deviations in the amount and seasonality of the flux.

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Section: Emission Budget Of the Baltic Seacontrasting

confidence: 52%

Section: Hg 0 Emission Fluxes Of the Baltic Sea And Other Marginal Seasmentioning

confidence: 99%

Section: Emission Budget Of the Baltic Seamentioning

confidence: 99%

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confidence: 99%

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High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

et al. 2018

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“…In this context it is notable that the only published air-sea CO 2 fluxes [Weiss et al, 2007] obtained with open-path instruments that agree with standard relationships were obtained in the Baltic Sea where salinity was very low (7-9 psu), resulting in relatively fresh spray and possibly less spray generation [Monahan, 1971;Wu, 2000].…”

Section: Introductionmentioning

confidence: 53%

Direct measurements of the CO₂ flux over the ocean: Development of a novel method

Prytherch

Yelland

Pascal

et al. 2010

Geophysical Research Letters

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[1] Over the ocean, eddy correlation measurements of the air-sea CO 2 flux obtained with open-path sensors have typically been an order of magnitude larger than those estimated by other techniques or sensors. It is shown here that this discrepancy is due to cross sensitivity to water vapor fluctuations: a novel correction procedure is demonstrated, tested against an independent data set and proved to be robust. After correction, the observed gas transfer velocities are in reasonable agreement with published values obtained using closed-path sensors or by tracer techniques. Data from open-path sensors may now be used for air-sea CO 2 flux estimation, greatly increasing the information available on air-sea gas transfer velocity. Citation: Prytherch, J., M. J.Yelland, R. W. Pascal, B. I. Moat, I. Skjelvan, and C. C. Neill (2010), Direct measurements of the CO 2 flux over the ocean: Development of a novel method, Geophys. Res. Lett., 37, L03607,

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The air‐water CO₂ exchange of a coastal sea—A sensitivity study on factors that influence the absorption and outgassing of CO₂ in the Baltic Sea

2015

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In this study, the BALTSEM model is used to estimate how air‐water CO2 fluxes in the Baltic Sea respond to parameterizations of organic alkalinity (Aorg), gas transfer, and phytoplankton growth, and further to changes in river loads. The forcing data include the most complete compilation of Baltic river loads for dissolved inorganic and organic carbon (DIC and DOC) and total alkalinity (TA). In addition, we apply the most recent estimates of internal TA generation in the system. Our results clearly demonstrate how air‐water CO2 fluxes of a coastal sea depend on river loads of carbon, TA, and nutrients as well the freshwater import itself. Long‐term changes in DIC loads are shown to be compensated by corresponding changes in air‐water CO2 exchange. By adding Aorg, a discrepancy in the carbonate system calculations was removed, and the simulated net CO2 absorption of the system decreased by 11%. A new parameterization for cyanobacteria growth significantly improved the seasonal development of pCO2 in the central Baltic Sea, although the net effect on CO2 fluxes was below 5%. By applying either a linear, quadratic, or cubic wind speed dependence for gas transfer, the long‐term net CO2 exchange was adjusted by less than 5%. There is no clear indication that any one of these parameterizations provides a more accurate estimate of CO2 fluxes than the other two. Our findings are applicable in other coastal areas that are heavily influenced by river loads of TA, DIC, and DOC.

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Evaluating transfer velocity-wind speed relationship using a long-term series of direct eddy correlation CO2 flux measurements

Cited by 61 publications

References 27 publications

High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

Direct measurements of the CO₂ flux over the ocean: Development of a novel method

The air‐water CO₂ exchange of a coastal sea—A sensitivity study on factors that influence the absorption and outgassing of CO₂ in the Baltic Sea

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Evaluating transfer velocity-wind speed relationship using a long-term series of direct eddy correlation CO2 flux measurements

Cited by 61 publications

References 27 publications

High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

High-resolution measurements of elemental mercury in surface water for an improved quantitative understanding of the Baltic Sea as a source of atmospheric mercury

Direct measurements of the CO2 flux over the ocean: Development of a novel method

The air‐water CO2 exchange of a coastal sea—A sensitivity study on factors that influence the absorption and outgassing of CO2 in the Baltic Sea

Contact Info

Product

Resources

About

Direct measurements of the CO₂ flux over the ocean: Development of a novel method

The air‐water CO₂ exchange of a coastal sea—A sensitivity study on factors that influence the absorption and outgassing of CO₂ in the Baltic Sea