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Table 2 CO2 fluxes and their uncertainties with different processing procedures

From: Comparative assessment of net CO2 exchange across an urbanization gradient in Korea based on eddy covariance measurements

FC (unit: μmol m−2 s−1)

Mean

Std.

25%

50%

75%

Default (double rotation & block averaging only)

8.8

7.3

2.3

7.8

14.4

Difference with default (EXP-default; unit: μmol m−2 s−1)

Coordinate rotation

 Triple rotation

− 0.1

1.5

0.0

0.0

0.1

 Planar fit [24]

− 0.8

3.8

− 1.7

− 0.5

0.3

 Planar fit [25]

− 1.0

3.9

− 1.9

− 0.6

0.3

Detrending

 Linear detrending

− 0.4

3.9

− 1.3

− 0.1

0.4

 Running mean 250 s

− 0.7

4.3

− 2.0

− 0.5

0.8

 Exponential running mean 250 s

− 0.9

3.8

− 2.0

− 0.6

0.2

Time Lags Compensation

 Covariance maximization

0.0

0.1

0.0

0.0

0.1

 Covariance maximization with default

0.1

0.1

0.0

0.0

0.1

 Automatic time lag Optimization

0.0

0.1

0.0

0.0

0.1

Spike count/removal

 Mauder et al. [26], accepted spikes 1–30%

− 0.5

1.4

− 0.3

0.0

0.0

 Vickers and Mahrt [27] (VM97), Max consecutive outliers (MCO) 3

− 0.1

0.2

− 0.1

0.0

0.0

 VM97, MCO 10

− 0.2

0.4

− 0.2

0.0

0.0

 VM97, MCO 30

− 0.3

0.7

− 0.4

− 0.1

0.0

 VM97, MCO 50

− 0.4

0.8

− 0.4

− 0.1

0.0

 VM97, MCO 70

− 0.4

0.8

− 0.5

− 0.1

0.0

Amplitude resolution

 4–7 sigma, number of bins 50–150

0.0

0.1

0.0

0.0

0.1

Dropouts

 Accepted central dropouts 5–20%

0.0

0.1

0.0

0.0

0.1

Absolute limits

0.0

0.1

0.0

0.0

0.1

Skewness & Kurtosis

0.0

0.1

0.0

0.0

0.1

Discontinuities

0.0

0.1

0.0

0.0

0.1

Spectral correction

 Low-frequency range [28]

0.3

0.4

0.1

0.2

0.4

 High-frequency range (HFR) [29]

0.1

0.2

0.0

0.1

0.2

 HFR [30, 31]

0.7

1.0

0.2

0.4

0.8

 HFR [32]

0.2

0.3

0.0

0.1

0.4

 HFR [33] with Horst and Lenschow [34] (HL09): along-wind, cross, and vertical winds

0.1

0.2

0.0

0.1

0.2

 HFR [33] with HL09: only cross and vertical winds

0.1

0.1

0.0

0.1

0.2

 HFR [35] with HL09: along-wind, cross, and vertical winds

0.2

0.2

0.0

0.1

0.3

 HFR [35] with HL09: only cross and vertical winds

0.2

0.2

0.0

0.1

0.3

  1. Data period is 1-month (March 2015) from HU site. Italic indicates the methods applied in this study