Regional carbon dioxide and energy fluxes from airborne observations using flight-path segmentation based on landscape characteristics

[摘要] This paper presents an analysis of regional fluxes obtained with a smallaircraft over heterogeneous terrain in the south-west of France, during thelarge scale field experiment CERES'07. We use a method combining variableflight-path segmentation with basic airborne footprint analysis. Thesegmentation is based on topography, land use and soil type, using a.o.satellite imagery and digital maps. The segments are delineated using anaverage footprint length, based on all flights, and segment lengths, whichare variable in space but not in time. The method results in segment averagedcarbon and energy fluxes, which are shown to be representative of regionalfluxes. Our analysis is focussed on carbon dioxide, heat and evaporativefluxes around solar noon. We will show that spatial and seasonal variationsin the fluxes can be linked to the underlying landscape. In addition, acomparison between the airborne data and ground flux data is made to supportour results. However, due to the incompleteness of ground data for somepredominant vegetation types (even in such a data dense context), upscalingof ground data to regional fluxes was not possible. Without the comparison,we are still able to demonstrate that aircraft can provide direct andmeaningful estimates of regional fluxes of energy and carbon dioxide.

[学科分类] 地球化学与岩石