THE CHAMBER CONFIGURATION IMPACT ON SOIL FLUX PRECISION USING CAVITY RING-DOWN SPECTROSCOPY

ABSTRACT

The Greenhouse gas (GHG) emission reduction is one of goals of environmental policy in climate change context. The accuracy of Soil flux measurements is one of scientific challenges during last decades. The soil flux measurement methodology using gas chromatography is described and commonly used. However cavity ring down spectroscopy is relatively new technology and there is need to research optimal chamber configuration and measurement time.
The aim of this study is to evaluate three types of static chamber configurations: with air compensation tube, with air circulation gap and without air compensation. To limit sunlight impact chambers were covered. Measurements were done during one day period in the same research plot changing only chamber configuration with Picarro G2508 cavity ring – down spectrometer. Research plot is non-agricultural grassland without nitrogen input on mineral soil resulting low concentration measurements. Statistical analyses were done for the concentration fluctuations slope of three gasses CO2, N2O and CH4 using linear regression and determination coefficient graphical analyse.
Analyse of results show that there is differences of soil flux results between chamber configurations. The chamber configuration with air compensation tube show more stable soil flux results.

Keywords: soil flux, ring-down spectroscopy, greenhouse gases, chamber configuration