Preprints
https://doi.org/10.5194/npg-2021-27
https://doi.org/10.5194/npg-2021-27

  26 Aug 2021

26 Aug 2021

Review status: this preprint is currently under review for the journal NPG.

Intrinsic non-stationarity of carbon dioxide turbulent fluxes in the urban boundary layer

Lei Liu1, Yu Shi1, and Fei Hu1,2 Lei Liu et al.
  • 1LAPC, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029
  • 2University of Chinese Academy of Sciences, Beijing, 100049

Abstract. Stationarity is a critical assumption in the eddy-covariance method that is widely used to calculate turbulent fluxes. Many methods have been proposed to diagnose non-stationarity attributed to external non-turbulent flows. In this paper, we focus on intrinsic non-stationarity (IN) attributed to turbulence randomness. The detrended fluctuation analysis is used to quantify IN of CO2 turbulent fluxes in the downtown of Beijing. Results show that the IN is widespread in CO2 turbulent fluxes and is a small-scale phenomenon related to the inertial sub-range turbulence. The small-scale IN of CO2 turbulent fluxes can be simulated by the Ornstein-Uhlenbeck (OU) process as a first approximation. Basing on the simulation results, we find that the average time should be greater than 27 s to avoid the effects of IN. Besides, the non-stationarity diagnosis methods that do not take into account IN would possibly make a wrong diagnosis with some parameters.

Lei Liu et al.

Status: open (until 21 Oct 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Lei Liu et al.

Lei Liu et al.

Viewed

Total article views: 166 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
146 17 3 166 1 1
  • HTML: 146
  • PDF: 17
  • XML: 3
  • Total: 166
  • BibTeX: 1
  • EndNote: 1
Views and downloads (calculated since 26 Aug 2021)
Cumulative views and downloads (calculated since 26 Aug 2021)

Viewed (geographical distribution)

Total article views: 146 (including HTML, PDF, and XML) Thereof 146 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 16 Sep 2021
Download
Short summary
We find a new kind of non-stationarity. This new kind of non-stationarity is caused by the intrinsic randomness. Results show that the new kind of non-stationarity is widespread in small-scale variations of CO2 turbulent fluxes. This finding reminds us that we need to handle the short-term averaged turbulent fluxes carefully, and we also need to re-screen the existing non-stationarity diagnosis methods because they could make a wrong diagnosis due to this new kind of non-stationarity.