Biosphere-Atmosphere Gas Exchange Measurements using Fourier Transform Infrared Spectrometry

Abstract

Field measurements of biosphere-atmosphere gas exchange are of great importance because they provide the possibility to study greenhouse gas dynamics and its feedback mechanisms in detail. This thesis contributes to the further development of concentration and flux measurement techniques to study biosphere-atmosphere exchange processes, by exploring the possibilities of using an in-situ Fourier Transform Infrared (FTIR)-analyzer for ecosystem research. This instrument is capable of measuring CO2, CH4, N2O, CO, and delta13CO2 simultaneously. It was combined with different flux measurement techniques, such as the flux gradient technique, the ratio-nocturnal boundary layer technique, and the flux chamber technique. The system was used in four different field campaigns and several laboratory studies. This thesis focuses on the use of the system to a) apply and assess different (new) flux measurement techniques, and b) study different flux and ecosystem processes.