Natural variability in air–sea gas transfer efficiency of CO2

被引:0
作者
Mingxi Yang
Timothy J. Smyth
Vassilis Kitidis
Ian J. Brown
Charel Wohl
Margaret J. Yelland
Thomas G. Bell
机构
[1] Plymouth Marine Laboratory,
[2] National Oceanography Centre,undefined
来源
Scientific Reports | / 11卷
关键词
D O I
暂无
中图分类号
学科分类号
摘要
The flux of CO2 between the atmosphere and the ocean is often estimated as the air–sea gas concentration difference multiplied by the gas transfer velocity (K660). The first order driver for K660 over the ocean is wind through its influence on near surface hydrodynamics. However, field observations have shown substantial variability in the wind speed dependencies of K660. In this study we measured K660 with the eddy covariance technique during a ~ 11,000 km long Southern Ocean transect. In parallel, we made a novel measurement of the gas transfer efficiency (GTE) based on partial equilibration of CO2 using a Segmented Flow Coil Equilibrator system. GTE varied by 20% during the transect, was distinct in different water masses, and related to K660. At a moderate wind speed of 7 m s−1, K660 associated with high GTE exceeded K660 with low GTE by 30% in the mean. The sensitivity of K660 towards GTE was stronger at lower wind speeds and weaker at higher wind speeds. Naturally-occurring organics in seawater, some of which are surface active, may be the cause of the variability in GTE and in K660. Neglecting these variations could result in biases in the computed air–sea CO2 fluxes.
引用
收藏
相关论文
共 116 条
[1]  
Khatiwala S(2013)Global ocean storage of anthropogenic carbon Biogeosciences 10 2169-2191
[2]  
Friedlingstein P(2019)Global carbon budget 2019 Earth Syst. Sci. Data. 11 1783-1838
[3]  
Takahashi T(2012)The changing carbon cycle in the Southern Ocean Oceanography 25 26-37
[4]  
Frölicher TL(2015)Dominance of the Southern Ocean in anthropogenic carbon and heat uptake in CMIP5 models J. Clim. 28 862-886
[5]  
Landschützer P(2015)The reinvigoration of the Southern Ocean carbon sink Science 349 1221-1224
[6]  
Woolf DK(2019)Key uncertainties in the recent air–sea flux of CO Glob. Biogeochem. Cycl. 33 1548-1563
[7]  
Wanninkhof R(2009)Advances in quantifying air–sea gas exchange and environmental forcing Ann. Rev. Mar. Sci. 1 213-244
[8]  
Asher WE(2011)Direct covariance measurement of CO2 gas transfer velocity during the 2008 Southern ocean gas exchange experiment: Wind speed dependency J. Geophys. Res. 116 C00F10-7230
[9]  
Ho DT(2016)Air–sea exchange of carbon dioxide in the Southern Ocean and Antarctic marginal ice zone Geophys. Res. Lett. 43 7223-4315
[10]  
Sweeney CS(2018)Using eddy covariance to measure the dependence of air–sea CO2 exchange rate on friction velocity Atm. Chem. Phys. 18 4297-8062