Multiple quality tests for analysing CO₂ fluxes in a beech temperate forest

B. Longdoz (1) , P. Gross (1) , A. Granier (1)

1 EEF - Ecologie et Ecophysiologie Forestières [devient SILVA en 2018]

The eddy covariance (EC) measurements are widely used to estimate the amount of carbon sequestrated by terrestrial biomes. The data quality and the selection of the correct EC records become an important step in the CO₂ flux determination procedure. In this paper an innovative combination of existing assessment tests is used to give a relatively complete evaluation of the net ecosystem exchange measurements. For the 2005 full-leaf season at the Hesse site, the percentage of bad quality data is relatively high (59.6%) especially during night-time (68.9%). This result strengthens the importance of the data gap filling method. The filtering used does not lead to a real improvement of the accuracy of the relationship between the CO₂ fluxes and the climatic factors. The soil respiration spatial heterogeneity (on a site with relatively homogenous vegetation pattern) seems to be too important to allow this improvement. However, the data rejected present some common characteristics. Their removal lead to a 10% increase in the total amount of CO₂ respired and photosynthesised during the 2005 full-leaf season. Consequently the application of our combination of multiple quality tests is able improve the inter-annual analysis. The question of a systematic application on the large database like the CarboEurope and FLUXNET is legitimate.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]; Interfaces continentales, environnement; Océan, Atmosphère; Sciences de la Terre

B. Longdoz, P. Gross, A. Granier. Multiple quality tests for analysing CO₂ fluxes in a beech temperate forest. Biogeosciences Discussions, 2007, 4 (6), pp.4197-4228. ⟨hal-00330276⟩