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Korean Meteorological Society (한국기상학회)
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Uncertainty Analysis of the Eddy-Covariance Turbulent Fluxes Measured over a Heterogeneous Urban Area: A Coordinate Tilt Impact

비균질 도시 지표에서 측정된 에디 공분산 난류 플럭스의 불확실성 분석: 좌표계 편향 영향

  • Lee, Doo-Il (Department of Atmospheric Science, Kongju National University) ;
  • Lee, Jae-Hyeong (Department of Atmospheric Science, Kongju National University) ;
  • Lee, Sang-Hyun (Department of Atmospheric Science, Kongju National University)
  • 이두일 (공주대학교 자연과학대학 대기과학과) ;
  • 이재형 (공주대학교 자연과학대학 대기과학과) ;
  • 이상현 (공주대학교 자연과학대학 대기과학과)
  • Received : 2016.07.18
  • Accepted : 2016.09.13
  • Published : 2016.09.30
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Abstract

An accurate determination of turbulent fluxes over an urban area is a challenging task due to its morphological diversity and associated flow complexity. In this study, an eddy covariance (EC) method is applied over a highly heterogeneous urban area in a small city (Gongju), South Korea to investigate the quantitative influence of 'coordinate tilt' in determining the turbulent fluxes of sensible heat, latent heat, momentum, and carbon dioxide mass. Two widely-used coordinate transform methods are adopted and applied to eight directional sections centered on the site to analyze a 1-year period EC measurement obtained from the urban site: double rotation (DR) and planar fit (PF) transform. The results show that mean streamline planes determined by the PF method are distinguished from the sections, representing morphological heterogeneity of the site. The sectional pitch angles determined by the DR method also compare well with those in the PF method. Both the PF and DR methods show large variabilities in the determined streamline planes at each directional section, implying that flow patterns may form in a complicate way due to the surface heterogeneity. Resulting relative differences of the turbulent fluxes, defined by $(F_{DR}-F_{PF})/F_{DR}$, are found on average +13% in sensible heat flux, +21% in latent heat flux, +37% in momentum flux, and +26% in carbon dioxide mass flux, which are larger values than those reported previously for fairly homogeneous natural sites. The fractional differences depend significantly on wind direction, showing larger differences in northerly winds at the measurement site. It is also found that the relative fractional differences are negatively correlated with the mean wind speed at both stable/unstable atmospheric conditions. These results imply that EC turbulent fluxes determined over heterogeneous urban areas should be carefully interpreted with considering the uncertainty due to 'coordinate tilt' effect in their applications.

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References

  1. Aubinet, M., T. Vesala, and D. Papale, Eds., 2012: Eddy covariance: a practical guide to measurement and data analysis. Springer, 438 pp.
  2. Baldocchi, D. D., B. B. Hincks, and T. P. Meyers, 1998: Measuring biosphere-atmosphere exchange of biologically related gasses with micrometeorological methods. Ecology, 69, 1331-1340.
  3. Baldocchi, D. D., and Coauthors, 2001: FLUXNET: a new tool to study the temporal and spatial variability of ecosystem- scale carbon dioxide, water vapor, and energy flux densities. Bull. Amer. Meteor. Soc., 82, 2415- 2434, doi:10.1175/1520-0477.
  4. Foken, T., and B. Wichura, 1996: Tools for quality assessment of surface-based flux measurements. Agric. For. Meteor., 78, 83-105. https://doi.org/10.1016/0168-1923(95)02248-1
  5. Foken, T., M. Göckede, M. Mauder, L. Mahrt, B. Amiro, and W. Munger, 2004: Post-field data quality control. Handbook of Micrometeorology, W. Lee, W. Massman, and B. E. Law, Eds., Kluwer Academic Publishers, 181-208.
  6. Grimmond, C. B. S., J. A. Salmond, T. R. Oke, B. Offerle, and A. Lemonsu, 2004: Flux and turbulence measurements at a densely built-up site in Marseille: Heat, mass (water and carbon dioxide), and momentum. J. Geophys. Res., 109, D24, doi:10.1029/2004JD004936.
  7. Hong, J., and J. Kim, 2002: On processing raw data from micrometeorological field experiments. Korean J. Agri. Forest Meteor., 4, 119-126.
  8. Jarvi, L., U. Rannik, I. Mammarella, A. Sogachev, P. P. Aalto, P. Keronen, E. Siivola, M. Kulmala, and T. Vesala, 2009: Annual particle flux observations over a heterogeneous urban area. Atmos. Chem. Phys., 9, 7847-7856. https://doi.org/10.5194/acp-9-7847-2009
  9. Kim, S., Y.-H. Lee, K. R. Kim, and Y.-S. Park, 2014: Analysis of surface energy balance closure over heterogeneous surfaces. Asia-Pac. J. Atmos. Sci., 50, 553-565, doi:10.1007/s13143-014-0045-2.
  10. Kotthaus, S., and C. S. B. Grimmond, 2014: Energy exchange in a dense urban environment-Part I: Temporal variability of long-term observations in central London. Urban Climate, 10, 261-280, doi:10.1016/ j.uclim.2013.10.002.
  11. Lee, S.-H., 2015a: LAS-derived determination of surfacelayer sensible heat flux over a heterogeneous urban area. Atmosphere, 25, 193-203 (in Korean with English abstract). https://doi.org/10.14191/Atmos.2015.25.2.193
  12. Lee, S.-H., J.-H. Lee, and B.-Y. Kim, 2015: Estimation of turbulent sensible heat and momentum fluxes over a heterogeneous urban area using a large aperture scintillometer. Adv. Atmos. Sci., 32, 1092-1105, doi:10. 1007/s00376-015-4236-2. https://doi.org/10.1007/s00376-015-4236-2
  13. Lee, X., W. J. Massman, and B. Law, Eds., 2004: Handbook of micrometeorology: a guide for surface flux measurement and analysis. Kluwer, 250 pp.
  14. Lee, Y.-H., 2015b: Characteristics of wind direction shear and momentum fluxes within roughness sublayer over sloping terrain. Atmosphere, 25, 591-600 (in Korean with English abstract). https://doi.org/10.14191/Atmos.2015.25.4.591
  15. Lee, Y.-H., B. Lee, K. Kahng, S.-J. Kim, and S.-O. Hong, 2013: Quality control and characteristic of eddy covariance data in the region of Nakdong river. Atmosphere, 23, 307-320 (in Korean with English abstract). https://doi.org/10.14191/Atmos.2013.23.3.307
  16. Li, M., W. Babel, K. Tanaka, and T. Foken, 2013: Note on the application of planar-fit rotation for non-omnidirectional sonic anemometers. Atmos. Meas. Tech., 6, 221-229, doi:10.5194/amt-6-221-2013.
  17. McMillen, R. T., 1988: An eddy correlation technique with extended applicability to non-simple terrain. Bound.- Layer Meteor., 43, 231-245. https://doi.org/10.1007/BF00128405
  18. Mestayer, P., and Coauthors, 2005: The urban boundary layer field experiment over Marseille UBL/CLUESCOMPTE: experimental set-up and first results. Bound.-Layer Meteor., 114, 315-365. https://doi.org/10.1007/s10546-004-9241-4
  19. Park, S.-J., T.-J. Choi, and S.-J. Kim, 2013: Heat flux variations over sea ice observed at the coastal area of the Sejong station, Antarctica. Asia-Pac. J. Atmos. Sci., 49, 443-450, doi:10.1007/s13143-013-0040-z.
  20. Ross, A. N., and E. R. Grant, 2015: A new continuous planar fit method for calculating fluxes in complex forested terrain. Atmos. Sci. Let., 16, 445-452, doi:10.1002/asl.580.
  21. Ruppert, J., M. Mauder, C. Thomas, and J. Luers, 2006: Innovative gapfilling strategy for annual sums of $CO_2$ net ecosystem exchange. Agric. Forest Meteorol., 138, 5-18. https://doi.org/10.1016/j.agrformet.2006.03.003
  22. Schmid, H. P., C. S. B. Grimmond, F. Cropley, B. Offerle, and H.-H. Su, 2000: Measurements of CO2 and energy fluxes over a mixed hardwood forest in the mid-western United States. Agric. Forest Meteorol., 103, 357-374. https://doi.org/10.1016/S0168-1923(00)00140-4
  23. Shimizu, T., 2015: Effect of coordinate rotation systems on calculated fluxes over a forest in complex terrain: a comprehensive comparison. Bound.-Layer Meteor., 156, 277-301, doi:10.1007/s10546-015-0027-7.
  24. Sun, J., 2007: Tilt corrections over complex terrain and their implication for $CO_2$ transport. Bound.-Layer Meteor., 124, 143-159, doi:10.1007/s10546-007-9186-5.
  25. Tanner, C. B., and G. W. Thurtell, 1969: Anemoclinometer measurements of Reynolds stress and heat transport in the atmospheric surface layer. Research and Development Technical Report ECOM 66-G22-F to the US Army Electronics Command, 200 pp.
  26. Tsukamoto, O., and F. Kondo, 2008: Experimental validation of the Webb correction for $CO_2$ flux with an open-path gas analyzer. 18th Symposium on Boundary Layers and Turbulence, Stockholm University, 5 pp.
  27. Velasco, E., and Coauthors, 2009: Eddy covariance flux measurements of pollutant gases in urban Mexico City. Atmos. Chem. Phys., 9, 7325-7342, doi:10.5194/acp-9-7325-2009.
  28. Vickers, D., and L. Mahrt, 1997: Quality control and flux sampling problems for tower and aircraft data. J. Atmos. Oceanic Technol., 14, 512-526, doi:10.1175/1520-0426(1997)014<0512:QCAFSP>2.0.CO;2.
  29. Webb, E. K., G. I. Pearman, and R. Leuning, 1980: Correction of flux measurement for density effects due to heat and water vapour transfer. Quart. J. Roy. Meteor. Soc., 106, 85-100, doi:10.1002/qj.49710644707.
  30. Wilczak, J. M., S. P. Oncley, and S. A. Sage, 2001: Sonic anemometer tilt correction algorithms. Bound.-Layer Meteor., 99, 127-150. https://doi.org/10.1023/A:1018966204465
  31. Yuan, R., M. Kang, S. Park, J. Hong, D. Lee, and J. Kim, 2007: The effect of coordinate rotation on the eddy covariance flux estimation in a hilly KoFlux forest catchment. Korean J. Agri. Forest Meteor., 9, 100-108. https://doi.org/10.5532/KJAFM.2007.9.2.100
  32. Yuan, R., M. Kang, S.-B. Park, J. Hong, D. Lee, and J. Kim, 2011: Expansion of the planar-fit method to estimate flux over complex terrain. Meteorol. Atmos. Phys., 110, 123-133, doi:10.1007/s00703-010-0113-9.
  33. Zeweldi, D. A., M. Gebremichael, J. Wang, T. Sammis, J. Kleissl, and D. Miller, 2010: Intercomparison of sensible heat flux from large aperture scintillometer and eddy covariance methods: field experiment over a heterogeneous semi-arid region. Bound.-Layer Meteor., 135, 151-159, doi:10.1007/s/10546-009-9460-9.