Umweltphysik

Monitoring natural CO2 emissions using a low-cost sensor network

Assessing and quantifying carbon dioxide emissions from the soil are ongoing challenges in a field site in the Upper Neckar Valley, South-western Germany. In this region carbon dioxide exits the soil in gaseous form by mofettes and can accumulate in the lower atmosphere. The exchange between the soil and the lower atmosphere has so far not been under scientific investigation and the exact amounts of leaked CO2 is unknown. These emissions are believed to be linked to volcanic activity in the region and can be of interest in improving understanding of geological CO2 storage and the impact of such leakage on the environment.
This goal of this project is the establishment of a long-term monitoring solution. To distribute the measurement over the heterogeneous area the installation of a network of low-cost CO$_2$ sensors in combination with a micro-meteorological eddy-covariance (EC) station is proposed. First preliminary field results using low-cost sensors found increased CO2 concentration values in immediate proximity to mofettes during daytime. Concentration was found to decrease with distance to mofettes and height above ground. At night measured concentration levels increased significantly. Due to the low-cost nature of the sensors, these results are not very reliable, yet. The addition of an EC station provides valuable reference data for validation. A long term deployment of such a sensor network will allow a more reliable assessment of the CO2 leakage in the area.