Open AccessCarbon dioxide uptake of a forested region in southwest France derived from airborne CO 2 and CO measurements in a quasi‐Lagrangian experiment
Author(s) -
Schmitgen Sandra,
Geiß Heiner,
Ciais Philippe,
Neininger Bruno,
Brunet Yves,
Reichstein Markus,
Kley Dieter,
VolzThomas Andreas
Publication year - 2004
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003jd004335
Subject(s) - eddy covariance , environmental science , atmospheric sciences , lagrangian , flux (metallurgy) , homogeneous , carbon dioxide , vegetation (pathology) , ecosystem , geology , physics , materials science , chemistry , ecology , organic chemistry , mathematical physics , biology , thermodynamics , medicine , pathology , metallurgy
This paper presents a Lagrangian budgeting approach to quantify the uptake of CO 2 by vegetation at horizontal scales of several tens of kilometers. For this purpose, CO 2 and meteorological parameters were measured from a small aircraft during four flights in June 2001 over a flat homogeneous and productive temperate forest in the Landes region (southwestern France). Additional CO measurements were made in order to identify and quantify the potential influence of anthropogenic emissions on the net CO 2 flux derived from the measurements. For one of four flights, Lagrangian conditions were nearly perfectly fulfilled. On average, the CO 2 mixing ratio in the boundary layer decreased at a rate of 0.11 ppm km −1 , yielding an average CO 2 uptake by the forest of 16 ± 2.5 μmol m −2 s −1 between 1230 and 1430 UT. Our result is about 15% smaller than the local net ecosystem exchange measured by eddy covariance at a tower north of the flight domain and about 12% higher than a regional estimate based on remote sensing data for the whole experimental area. The contribution of anthropogenic emissions to the regional CO 2 budget was estimated from the CO measurements to be to <0.5 μmol m −2 s −1 .