Boundary-Layer Meteorology

, Volume 126, Issue 2, pp 209–218 | Cite as

Consequences of Uncertainties in CO2 Density for Estimating Net Ecosystem CO2 Exchange by Open-path Eddy Covariance

  • Penélope Serrano-OrtizEmail author
  • Andrew S. Kowalski
  • Francisco Domingo
  • Borja Ruiz
  • Lucas Alados-Arboledas
Original Paper


Errors in the estimation of CO2 surface exchange by open-path eddy covariance, introduced during the removal of density terms [Webb et al. Quart J Roy Meteorol Soc 106:85–100, (1980) - WPL], can happen both because of errors in energy fluxes [Liu et al. Boundary-Layer Meteorol 120:65–85, (2006)] but also because of inaccuracies in other terms included in the density corrections, most notably due to measurements of absolute CO2 density (ρ c ). Equations are derived to examine the propagation of all errors through the WPL algorithm. For an open-path eddy covariance system operating in the Sierra de Gádor in south-east Spain, examples are presented of the inability of an unattended, open-path infrared gas analyzer (IRGA) to reliably report ρ c and the need for additional instrumentation to determine calibration corrections. A sensitivity analysis shows that relatively large and systematic errors in net ecosystem exchange (NEE) can result from uncertainties in ρ c in a semi-arid climate with large sensible heat fluxes (H s ) and (wet) mineral deposition. When ρc is underestimated by 5% due to lens contamination, this implies a 13% overestimation of monthly CO2 uptake.


Density correction Eddy covariance Error propagation Open-path infrared gas analyzer 


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Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  • Penélope Serrano-Ortiz
    • 1
    • 2
    Email author
  • Andrew S. Kowalski
    • 1
    • 2
  • Francisco Domingo
    • 3
    • 4
  • Borja Ruiz
    • 1
    • 2
  • Lucas Alados-Arboledas
    • 1
    • 2
  1. 1.Departamento de Física AplicadaUniversidad de GranadaGranadaSpain
  2. 2.Centro Andaluz de Medio Ambiente (CEAMA)GranadaSpain
  3. 3.Estación Experimental de Zonas Áridas, CSICAlmeríaSpain
  4. 4.Departamento de Biología Vegetal y Ecología, Escuela Politécnica SuperiorUniversidad de AlmeríaAlmeríaSpain

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