Eddy covariance measurements of turbulent fluxes in the surf zone

Yongfeng Qi; Xiaodong Shang; Guiying Chen; Linghui Yu

doi:10.1007/s13131-020-1562-8

Volume 39 Issue 3

Apr. 2020

Turn off MathJax

Article Contents

Article Navigation > Acta Oceanologica Sinica > 2020 > 39(3): 63-72

Yongfeng Qi, Xiaodong Shang, Guiying Chen, Linghui Yu. Eddy covariance measurements of turbulent fluxes in the surf zone[J]. Acta Oceanologica Sinica, 2020, 39(3): 63-72. doi: 10.1007/s13131-020-1562-8

Citation:

Yongfeng Qi, Xiaodong Shang, Guiying Chen, Linghui Yu. Eddy covariance measurements of turbulent fluxes in the surf zone[J]. Acta Oceanologica Sinica, 2020, 39(3): 63-72. doi: 10.1007/s13131-020-1562-8

Citation:

PDF( 1411 KB)

Eddy covariance measurements of turbulent fluxes in the surf zone

doi: 10.1007/s13131-020-1562-8

State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China

Funds: The National Natural Science Foundation of China under contract Nos 41876023, 41630970 and 41876022; the Instrument Developing Project of the Chinese Academy of Sciences under contract No. YZ201432; the Guangzhou Science and Technology Project under contract No. 201707020037; the National Key R&D Plan of China under contract Nos 2017YFC0305804 and 2017YFC0305904.

More Information

Corresponding author: E-mail: xdshang@scsio.ac.cn
Received Date: 2019-07-04
Accepted Date: 2019-08-16

Available Online: 2020-04-21

Publish Date: 2020-03-25

Abstract

Abstract

Turbulent eddies play a critical role in oceanic flows. Direct measurements of turbulent eddy fluxes beneath the sea surface were taken to study the direction of flux-carrying eddies as a means of supplementing our understanding of vertical fluxes exchange processes and their relationship to tides. The observations were made at 32 Hz at a water depth of ~1.5 m near the coast of Sanya, China, using an eddy covariance system, which mainly consists of an acoustic doppler velocimeter (ADV) and a fast temperature sensor. The cospectra-fit method—an established semi-empirical model of boundary layer turbulence to the measured turbulent cospectra at frequencies below those of surface gravity waves—was used in the presence of surface gravity waves to quantify the turbulent eddy fluxes (including turbulent heat flux and Reynolds stress). As much as 87% of the total turbulent stress and 88% of the total turbulent heat flux were determined as being at band frequencies below those of surface gravity waves. Both the turbulent heat flux and Reynolds stress showed a daily successive variation; the former peaked during the low tide period and the later peaked during the ebb tide period. Estimation of roll-off wavenumbers, k₀, and roll-off wavelengths, λ₀ (where λ₀=2π/k₀), which were estimated as the horizontal length scales of the dominant flux-carrying turbulent eddies, indicated that the λ₀ of the turbulent heat flux was approximately double that of the Reynolds stress. Wavelet analysis showed that both the turbulent heat flux and the Reynolds stress have a close relationship to the semi-diurnal and diurnal tides, and therefore indicate the energy that is transported from tides to turbulence.
- eddy covariance,
- turbulent fluxes,
- surface gravity waves,
- cospectrum,
- tides

FullText(HTML)

References(28)

References

[1]	Berg P, Glud R N, Hume A, et al. 2009. Eddy correlation measurements of oxygen uptake in deep ocean sediments. Limnology and Oceanography, 7(8): 576–584
[2]	Berg P, Røy H, Janssen F, et al. 2003. Oxygen uptake by aquatic sediments measured with a novel non-invasive eddy-correlation technique. Marine Ecology Progress Series, 261: 75–83. doi: 10.3354/meps261075
[3]	Berg P, Røy H, Wiberg P L. 2007. Eddy correlation flux measurements: the sediment surface area that contributes to the flux. Limnology and Oceanography, 52(4): 1672–1684. doi: 10.4319/lo.2007.52.4.1672
[4]	Bowden K F, Fairbairn L A. 1956. Measurements of turbulent fluctuations and Reynolds stresses in a tidal current. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 237(1210): 422–438
[5]	Crusius J, Berg P, Koopmans D J, et al. 2008. Eddy correlation measurements of submarine groundwater discharge. Marine Chemistry, 109(1–2): 77–85. doi: 10.1016/j.marchem.2007.12.004
[6]	Gerbi G P, Trowbridge J H, Edson J B, et al. 2008. Measurements of momentum and heat transfer across the air-sea interface. Journal of Physical Oceanography, 38(5): 1054–1072. doi: 10.1175/2007JPO3739.1
[7]	Grinsted A, Moore J C, Jevrejeva S. 2004. Application of the cross wavelet transform and wavelet coherence to geophysical time series. Nonlinear Processes in Geophysics, 11(5–6): 561–566
[8]	He Guowei, Zhang Jinbai. 2006. Elliptic model for space-time correlations in turbulent shear flows. Physical Review E, 73(5): 055303. doi: 10.1103/PhysRevE.73.055303
[9]	Heathershaw A D. 1979. The turbulent structure of the bottom boundary layer in a tidal current. Geophysical Journal International, 58(2): 395–430. doi: 10.1111/j.1365-246X.1979.tb01032.x
[10]	Kaimal J Y, Izumi J C, Cote O R. 1972. Spectral characteristics of surface-layer turbulence. Quarterly Journal of the Royal Meteorological Society, 98: 563–589. doi: 10.1002/qj.49709841707
[11]	Katul G, Cava D, Poggi D, et al. 2004. Stationarity, homogeneity, and ergodicity in canopy turbulence. In: Lee X H, Massman W, Law B, eds. Handbook of Micrometeorology: A Guide for Surface Flux Measurement and Analysis. Dordrecht: Springer, 84–102
[12]	Kirincich A R, Lentz S J, Gerbi G P. 2010. Calculating Reynolds stresses from ADCP measurements in the presence of surface gravity waves using the cospectra-fit method. Journal of Atmospheric and Oceanic Technology, 27(5): 889–907. doi: 10.1175/2009JTECHO682.1
[13]	Kuwae T, Kamio K, Inoue T, et al. 2006. Oxygen exchange flux between sediment and water in an intertidal sandflat, measured in situ by the eddy-correlation method. Marine Ecology Progress Series, 307: 59–68. doi: 10.3354/meps307059
[14]	Lozovatsky I, Liu Zhiyu, Wei Hao, et al. 2008. Tides and mixing in the northwestern East China Sea, Part II: near-bottom turbulence. Continental Shelf Research, 28(2): 338–350. doi: 10.1016/j.csr.2007.08.007
[15]	Mei C C. 1989. The Applied Dynamics of Ocean Surface Waves. Singapore: World Scientific, 760
[16]	Priestley C H B, Swinbank W C. 1947. Vertical transport of heat by turbulence in the atmosphere. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 189(1019): 543–561
[17]	Reimers C E, Özkan-Haller H T, Berg P, et al. 2012. Benthic oxygen consumption rates during hypoxic conditions on the Oregon continental shelf: evaluation of the eddy correlation method. Journal of Geophysical Research, 117(C2): C02021. doi: 10.1029/2011JC007564
[18]	Shang X D, Qiu X L, Tong P, et al. 2003. Measured local heat transport in turbulent Rayleigh-Bénard convection. Physical Review Letters, 90(7): 074501. doi: 10.1103/PhysRevLett.90.074501
[19]	Shang X D, Qiu X L, Tong P, et al. 2004. Measurements of the local convective heat flux in turbulent Rayleigh-Bénard convection. Physical Review E, 70(2): 026308. doi: 10.1103/PhysRevE.70.026308
[20]	Shaw W J, Trowbridge J H. 2001. The direct estimation of near-bottom turbulent fluxes in the presence of energetic wave motions. Journal of Atmospheric and Oceanic Technology, 18(9): 1540–1557. doi: 10.1175/1520-0426(2001)018<1540:TDEONB>2.0.CO;2
[21]	Soulsby R. 1980. Selecting record length and digitization rate for near-bed turbulence measurements. Journal of Physical Oceanography, 10: 208–219. doi: 10.1175/1520-0485(1980)010<0208:SRLADR>2.0.CO;2
[22]	Tennekes H, Lumley J L. 1972. A First Course in Turbulence. Cambridge: MIT Press, 27–34
[23]	Torrence C, Compo G P. 1998. A practical guide to wavelet analysis. Bulletin of the American Meteorological Society, 79(1): 61–78. doi: 10.1175/1520-0477(1998)079<0061:APGTWA>2.0.CO;2
[24]	Trowbridge J H. 1998. On a technique for measurement of turbulent shear stress in the presence of surface waves. Journal of Atmospheric and Oceanic Technology, 15(1): 290–298. doi: 10.1175/1520-0426(1998)015<0290:OATFMO>2.0.CO;2
[25]	Trowbridge J, Scully M, Sherwood C R. 2018. The cospectrum of stress-carrying turbulence in the presence of surface gravity waves. Journal of Physical Oceanography, 48(1): 29–44. doi: 10.1175/JPO-D-17-0016.1
[26]	Warner J C, Sherwood C R, Arango H G, et al. 2005. Performance of four turbulence closure models implemented using a generic length scale method. Ocean Modelling, 8(1–2): 81–113. doi: 10.1016/j.ocemod.2003.12.003
[27]	Wyngaard J, Coté O. 1972. Cospectral similarity in the atmospheric surface layer. Quarterly Journal of the Royal Meteorological Society, 98: 590–603. doi: 10.1002/qj.49709841708
[28]	Yamamoto S, Kayanne H, Tokoro T, et al. 2015. Total alkalinity flux in coral reefs estimated from eddy covariance and sediment pore-water profiles. Limnology and Oceanography, 60(1): 229–241. doi: 10.1002/lno.10018