Identifying CO2 advection on a hill slope using information flow

Minseok Kang, Benjamin L. Ruddell, Chunho Cho, Junghwa Chun, Joon Kim

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

In hilly terrain affected by drainage flow, the horizontal advection of CO2 makes it difficult to accurately observe the net ecosystem exchange of CO2 by the eddy covariance technique. Downslope drainage can result in an overestimation of respiration at the bottom of a hill slope and an underestimation at the top, resulting in discrepancies among different flux corrections using filters based on the friction velocity, light response curve, and timing of advection. Vertical profiles of the CO2 concentration from the ground to above the canopy were measured along with above-canopy EC flux measurements at the top and bottom of a hill slope at the Gwangneung KoFlux sites from 2008 to 2010. To infer the timing, direction, temporal scale, and structure of CO2 advection from uphill to downhill, we constructed an information flow dynamical process network (DPN) based on the observed multi-level CO2 concentrations. A site-specific quality control filter was developed to eliminate data strongly affected by CO2 advection, which identifies the observations when strong downslope information flow exists in the DPN. This site-specific filter considerably reduced the discrepancies among different traditional flux corrections. This research provides a method for the general characterization of advection using information flow, and application of the method as a site-specific filter for eddy covariance observations in hilly and complex terrain.

Original languageEnglish (US)
Pages (from-to)265-278
Number of pages14
JournalAgricultural and Forest Meteorology
Volume232
DOIs
StatePublished - Jan 15 2017

Keywords

  • CO advection
  • Dynamical process network
  • Eddy covariance measurement
  • Forest hill slope
  • Information flow
  • Nighttime CO flux correction

ASJC Scopus subject areas

  • Forestry
  • Global and Planetary Change
  • Agronomy and Crop Science
  • Atmospheric Science

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