JOURNAL BROWSE
Search
Advanced SearchSearch Tips
Outlier Detection and Replacement for Vertical Wind Speed in the Measurement of Actual Evapotranspiration
facebook(new window)  Pirnt(new window) E-mail(new window) Excel Download
 Title & Authors
Outlier Detection and Replacement for Vertical Wind Speed in the Measurement of Actual Evapotranspiration
Park, Chun Gun; Rim, Chang-Soo; Lim, Kwang-Suop; Chae, Hyo-Sok;
  PDF(new window)
 Abstract
In this study, using flux data measured in Deokgokje reservoir watershed near Deokyu mountain in May, June, and July 2011, statistical analysis was conducted for outlier detection and replacement for vertical wind speed in the measurement of evapotranspiration based on eddy covariance method. To statistically analyze the outliers of vertical wind speed, the outlier detection method based on interquartile range (IQR) in boxplot was employed and the detected outliers were deleted or replaced with mean. The comparison was conducted for the measured evapotranspiration before and after the outlier replacement. The study results showed that there is a difference between evapotranspiration before outlier replacement and evapotranspiration after outlier replacement, especially during the rainy day. Therefore, based on the study results, the outliers should be deleted or replaced in the measurement of evapotranspiration.
 Keywords
Latent heat flux;Outliers;Eddy covariance;Statistical analysis;IQR rule;
 Language
Korean
 Cited by
 References
1.
AsiaFlux (2014). Available at: http://www.asiaflux.net/ (Accessed:August 12, 2014).

2.
CARBOAFRICA (2014). Available at: http://www.carboafrica.net/index_en.asp (Accessed: August 12, 2014).

3.
CarboEurope-IP (2014). Available at: http://www.carboeurope.org/(Accessed: August 12, 2014).

4.
Choi, T., Kim, J. and Lim J. H. (2003). "$CO_2$ exchange in Kwangneung broadleaf deciduous forest in a hilly terrain in the summer of 2002." Korean Journal of Agricultural and Forest meteorology, Vol. 5, No. 2, pp. 70-80.

5.
FLUXNET Oak Ridge National Laboratory (ORNL) (2014). Available at: http://fluxnet.ornl.gov (Accessed: August 12, 2014).

6.
Frank, J. M., Massman, W. J. and Ewers, B. E. (2013). "Underestimates of sensible heat flux due to vertical velocity measurement errors in non-orthogonal sonic anemometers." Agricultural and Forest Meteorology, Vol. 171-172, pp. 72-81. crossref(new window)

7.
Frigge, M., Hoaglin, D. and Iglewicz, B. (1989). "Some Implementations of the Boxplot." The American Statistician, Vol. 43, No. 1, pp. 50-54.

8.
Global Energy and Water Exchange Project-World Climate Research Programme (GEWEX WCRP) (2014). Available at: http://www.gewex.org/ (Accessed: August 12, 2014).

9.
Gockede, M., Rebmann, C. and Foken, T. (2004). "A combination of quality assessment tools for eddy covariance measurements with footprint modelling for the characteristics of complex sites." Agricultural and Forest Meteorology, Vol. 127, pp. 175-188. crossref(new window)

10.
Hawkins, D. (1980). Identification of Outliers, Chapman and Hall.

11.
Hong, J., Kwon, H., Lim, J. H., Byun, Y. H., Lee J. and Kim, J. (2009). "Standardization of KoFlux eddy-covariance data processing." Korean Journal of Agricultural and Forest Meteorology, Vol. 11, No. 1, pp. 19-26. crossref(new window)

12.
Humes, K. S., Kustas, W. P. and Moran, M. S. (1994). "Use of sensing and reference site measurements to estimate instaneous surface energy balance components over a semiarid energy balance." Water Resources Research, Vol. 30, No. 5, pp. 1363-1373. crossref(new window)

13.
Kang, K., Koo, H. J., Byon J. Y., Park, Y. S. and Jung, H. S. (2013). "Comparison of surface fluxes based on landuse characteristics near Gangjeong weir of the Nakdong river." Jour. Korean Earth Science Society, Vol. 34, No. 6, pp. 561-574. crossref(new window)

14.
Kim, H., Kim, H. and Um, H. (2003). "Surface flux observation in Haenam using eddy-covariance method." Proceeding of the 35th Meeting of KOSAE, Korean Society for Atmospheric Environment, pp. 415-416.

15.
Korean Meteorological Administration (KMA) (2013). "Advanced research on hydrolometeorology research." Korean Meteorological Administration, pp. 1-319.

16.
Kustas, W. P., Blanford, J. H., Stannard, D. I., Daughtry, C. S. T., Nichols, W. D. and Weltz, M. A. (1994). "Local energy flux estimates for unstable conditions using variance data in semiarid rangelands." Water Resources Research, Vol. 30, No. 5, pp. 1351-1361. crossref(new window)

17.
Kwon, H., Lee, J. H., Lee, Y. K., Lee, J. W., Jung, S. W. and Kim, J. (2009). "Seasonal variations of evapotranspiration observed in a mixed forest in the Seolmacheon catchment." Korean Journal of Agricultural and Forest meteorology, Vol. 11, No. 1, pp. 39-47. crossref(new window)

18.
Lee, H. C., Hong, J., Cho, C. H., Choi, B. C., Oh, S. N. and Kim, J. (2003). "Surface exchange of energy and carbon dioxide between the atmosphere and a farmland in Haenam, Korea." Korean Journal of Agricultural and Forest Meteorology, Vol. 5, No. 2, pp. 61-69.

19.
Lim, H. J. (2007). Processing and quality control of flux data at Gwangneung, Master Thesis, Kyungpook National University, South Korea.

20.
Max Planck Institute for Biogeochemistry (2014). Available at: http://www.bgc.mpg.de/public/ (Accessed: August 12, 2014).

21.
Moore, D. S. and McCabe, G. P. (1999). Introduction to the Practice of Statistics, 3rd ed. New york: W.H. Freeman and Company.

22.
National Research Foundation of Korea (NRF) (2004). Evaluation of evapotranspiration from rice paddies and forests in Korea based on eddy correlation method, Report (in Korean).

23.
Oak Ridge National Laboratory-Distributed Active Archive Center for Biochemical Dynamics (ORNL DAAC) (2011). Available at: http://daac.ornl.gov (Accessed: August 12, 2014).

24.
Oke, T. R. (1987). Boundary layer climates, Methuen Inc. 2nd Edition, NY.

25.
OzFlux (2014). Available at: http://www.ozflux.org.au/ (Accessed: August 12, 2014).

26.
Papale, D., Reichstein, M., Aubinet, M., Canforal, E., Bernhofer, C., Kutsch, W., Longdoz, B., Rambal, S., Valentinil, R., Vesala, T. and Yakir, D. (2006). "Towards a standardized processing of net ecosystem exchange measured with eddy covariance technique: Algorithms and Uncertainty Estimation." Biogeoscience, Vol. 3, pp. 571-583. crossref(new window)

27.
Park, Y. (2001). Evapotranspiration and its controlling factors in the two adjacent forests in Kwangneung Arboretum, Master Thesis, Department of Atmospheric Sciences, Yonsei University, Seoul, Korea.

28.
US-China Carbon Consortium (USCCC) (2014). Available at: http://research.eeescience.utoledo.edu/lees/research/USCCC/ (Accessed: August 12, 2014).

29.
Vickers, D. and Mahrt, L. (1997). "Quality control and flux sampling problems for tower and aircraft data." J. Atm. Oc. Tech., Vol. 14, pp. 512-526. crossref(new window)

30.
Wilczak, J., Oncley, S. P. and Stage, S. A. (2001). "Sonic anemometer tile correction algorithms." Boundary-Layer Meteorology, Vol. 99, pp. 127-150. crossref(new window)

31.
Yuan, R., Kang, M., Park, S., Hong, J., Lee, D. and Kim, J. (2007). "The effect of coordinate rotation on the eddy covariance flux estimation in a hilly KoFlux forest catchment." Korean Journal of Agricultural and Forest Meteorology, Vol. 9, pp. 100-108. crossref(new window)