Flow Distortion Calculations and Their Application in HEXMAX

Oost, W.A.; Fairall, C. W.; Edson, James B.; Smith, Stuart D.; Anderson, R.J.; Wills, J. A. B.; Katsaros, Kristina B.; DeCosmo, Janice

doi:10.1175/1520-0426(1994)011<0366:fdcata>2.0.co;2

Cited by 51 publications

(31 citation statements)

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“…It has been shown that the EC method is more sensitive to flow distortion than the ID method 21 which suggests that biases in EC-derived fluxes could be large. Biases in the EC fluxes can be estimated by comparison with the (corrected) ID fluxes, where available.…”

Section: Flux Calculation Methodsmentioning

confidence: 99%

AutoFlux: an autonomous system for the direct measurement of the air-sea fluxes of CO₂, heat and momentum

Yelland

Pascal

Taylor

et al. 2009

Journal of Operational Oceanography

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Section: Flux Calculation Methodsmentioning

confidence: 99%

AutoFlux: an autonomous system for the direct measurement of the air-sea fluxes of CO₂, heat and momentum

Yelland

Pascal

Taylor

et al. 2009

Journal of Operational Oceanography

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“…The tilt angle of the wind vector was on average 2-3", upward for instruments mounted above the boom and downward for instruments below (DeCosmo, 1991;Oost et al, 1994).…”

Section: Coping With Flow Distortionmentioning

confidence: 99%

“…Application of the "up-down" method to a set of pairs of sequential data runs with the sonic anemometer in turn "up" (above) and "down" (below the boom) yielded wind stress values for the two groups that were equal within lo%, whereas with only the tilt correction there was a systematic difference of 40% between the "ups" and "downs" (Smith et al, 1992;Oost et al, 1994). The ellipsoid correction was applied to the above-mentioned sonic anemometer and to a pressure anemometer, for which the flow distortion was smaller to begin with.…”

Section: Coping With Flow Distortionmentioning

confidence: 99%

The impact of the hexos programme

Smith

Katsaros

Oost

et al. 1996

Boundary-Layer Meteorol

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In HEXOS, aprogramme of coordinated laboratory, field andmodel studies, an international group of participants has extended the range of measurements of evaporation from the sea and has investigated the role of droplets in the transfer of water to the atmosphere. Predictions of a rapid rise in the evaporation coefficient at wind speeds above 15 m s-' have not been substantiated. Wind stress measurements showed a relationship with wave age. New methods were developed for coping with flow distortion.

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“…Other issues such as motion correction and airflow can also influence shipboard flux measurement (Landwehr et al, 2015). An additional complication is the generation of turbulence by the interaction of airflow with the vessel's structure, such as the leading edge of the hull and/or smaller support structures (Oost et al, 1994). The effect of this on the apparent gas flux is not well known, nor is whether advected atmospheric turbulence is affected by flow distortion.…”

Section: Introductionmentioning

confidence: 99%

Gradient flux measurements of sea–air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experiment

et al. 2018

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Abstract. Direct measurements of marine dimethylsulfide (DMS) fluxes are sparse, particularly in the Southern Ocean. The Surface Ocean Aerosol Production (SOAP) voyage in February-March 2012 examined the distribution and flux of DMS in a biologically active frontal system in the southwest Pacific Ocean. Three distinct phytoplankton blooms were studied with oceanic DMS concentrations as high as 25 nmol L −1 . Measurements of DMS fluxes were made using two independent methods: the eddy covariance (EC) technique using atmospheric pressure chemical ionization-mass spectrometry (API-CIMS) and the gradient flux (GF) technique from an autonomous catamaran platform. Catamaran flux measurements are relatively unaffected by airflow distortion and are made close to the water surface, where gas gradients are largest. Flux measurements were complemented by near-surface hydrographic measurements to elucidate physical factors influencing DMS emission. Individual DMS fluxes derived by EC showed significant scatter and, at times, consistent departures from the Coupled Ocean-Atmosphere Response Experiment gas transfer algorithm (COAREG). A direct comparison between the two flux methods was carried out to separate instrumental effects from environmental effects and showed good agreement with a regression slope of 0.96 (r 2 = 0.89). A period of abnormal downward atmospheric heat flux enhanced near-surface ocean stratification and reduced turbulent exchange, during which GF and EC transfer velocities showed good agreement but modelled COAREG values were significantly higher. The transfer velocity derived from near-surface ocean turbulence measurements on a spar buoy compared well with the COAREG model in general but showed less variation. This first direct comparison between EC and GF fluxes of DMS provides confidence in compilation of flux estimates from both techniques, as well as in the stable periods when the observations are not well predicted by the COAREG model.

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Flow Distortion Calculations and Their Application in HEXMAX

Cited by 51 publications

References 0 publications

AutoFlux: an autonomous system for the direct measurement of the air-sea fluxes of CO₂, heat and momentum

AutoFlux: an autonomous system for the direct measurement of the air-sea fluxes of CO₂, heat and momentum

The impact of the hexos programme

Gradient flux measurements of sea–air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experiment

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Flow Distortion Calculations and Their Application in HEXMAX

Cited by 51 publications

References 0 publications

AutoFlux: an autonomous system for the direct measurement of the air-sea fluxes of CO2, heat and momentum

AutoFlux: an autonomous system for the direct measurement of the air-sea fluxes of CO2, heat and momentum

The impact of the hexos programme

Gradient flux measurements of sea–air DMS transfer during the Surface Ocean Aerosol Production (SOAP) experiment

Contact Info

Product

Resources

About

AutoFlux: an autonomous system for the direct measurement of the air-sea fluxes of CO₂, heat and momentum

AutoFlux: an autonomous system for the direct measurement of the air-sea fluxes of CO₂, heat and momentum