Iso Drone - AiR Sampling with UAV

Currently sampling of the atmosphere for gas emission measurements has to be done by building towers or hiring airplanes - capital-intensive methods. Easy access to unmanned aerial vehicles (UAV) has opened-up new opportunities for remote gas sampling (e.g. greenhouse gases, VOCs and water vapour). The projects aim is to develop and produce modular UAV-based gas monitoring systems for emission and isotope measurements to substitute current technologies.

Call: Beyond Europe - Cooperative R&D Projects "Experimental Development"

Funded by: Austrian Research Promotion Agency (FFG), Sensengasse 1, 1090 Wien, Austria

Measuring the isotopic signature of carbon dioxide above an ecosystem reveals crucial information about the way in which the ecosystem in functioning and the balance between carbon sequestration and carbon flux. In this research we intend to develop test the ability of a gas sampling device developed by CombInnoTec to deliver reliable isotopic signatures of carbon dioxide fluxes, at different heights above the ecosystem canopy; a device that can be easily mounted on a commercially available drone or blimp or deployed within the canopy for automatic sampling (referred to from herein as drone based system).

• Overview on RESULTS of CASE STUDY: A good agreement between the µl CO2 and peak area off the FID with an R² = 0.972 was found - this suggests that FID could be used to measure the CO2 concentration in ambient gas samples and that we could get sufficiently accurate CO2 data necessary for the Keeling plot measurement. In principle the developed system was able to detect sufficient quantities of CO2 with isotopic measurements with an adequate precision.  This suggests the system could be retrofitted to accommodate the 12 ml gas tight vials that we have identified as the most cost effective and suitable for UAV-based sampling system. This requires that we move away from the current purge and trap system to a direct injection method, this would save considerable machine time (down from 20 minutes per sample to 7 minutes per sample measurement) and resources in terms of liquid nitrogen etc. It would also mean that we would have opportunity for repeated measurement of samples which might be issue to be taken into consideration.

Stable isotope values of carbon dioxide in ambient air, in the sample volumes we intend to collect via UAV were measured with sufficient accuracy and precision for the construction of Keeling plots.  Therefore the further development of an Iso-drone system for monitoring CO2 fluxes in urban and natural environments was rated as a viable and feasible technology to develop further. 

Principal Investigators: Florian Mayer (CombInnoTec / VSI), Rebecca Hood-Nowotny (AIT).

Call: Innovationsscheck 5000 (IsoDrone)

Funded by: Austrian Research Promotion Agency (FFG), Sensengasse 1, 1090 Wien, Austria

Call: Exploratory collaborative research project  (H20-Drone; RCN: 20489)

Funded by: UN Food and Agriculture Organisation/International Atomic Energy Agency (FAO/IAEA)

• Leitner, S., Feichtinger, W., Mayer, S., Mayer, F., Krompetz, D., Hood-Nowotny, R., & Watzinger, A. (2023). UAV-based sampling systems to analyse greenhouse gases and volatile organic compounds encompassing compound-specific stable isotope analysis. Atmospheric Measurement Techniques, 16(2), 513-527. https://doi.org/10.5194/amt-16-513-2023

The Keeling plot method is a powerful technique for analyzing the isotopic composition of carbon dioxide in the atmosphere. It is named after Charles David Keeling, who pioneered the method. The method involves measuring the stable isotopes of carbon (δ13C) in CO2 samples collected from the air. These isotopic signatures provide valuable information about the sources and sinks of atmospheric CO2 and the water use efficiency of ecosystems..

The Keeling plot method plots the δ13C values against the reciprocal of the CO2 concentration. This allows researchers to distinguish between different sources of CO2, such as fossil fuel emissions and natural carbon exchange processes. The slope of the Keeling plot provides information about the isotopic composition of the CO2 sources. Fossil fuel emissions have a distinct δ13C signature, while natural carbon exchange processes, such as photosynthesis (as affected by water use) and respiration, have different isotopic ratios.

Using this method, scientists can track changes in atmospheric CO2 composition over time and study carbon cycling, carbon assimilation and water use efficiency in different ecosystems. The Keeling plot method his instrumental in understanding the role of human activities / land use in altering the isotopic composition of atmospheric CO2 and its implications for climate change.

The novel UAV-based whole-air sampler AS-110, developed within the ISO-drone project,has proven to be well suited to collect CO2 samples from different heights in the stratosphere for Keeling analysis.

Classical read: Pataki, D. E., Ehleringer, J. R., Flanagan, L. B., Yakir, D., Bowling, D. R., Still, C. J., ... & Berry, J. A. (2003). The application and interpretation of Keeling plots in terrestrial carbon cycle research. Global biogeochemical cycles, 17(1).