ESRIG-EES colloquium: Meis Uijttewaal, MSc EES student

Title: Suitability of Multi-Layer Foil bags for the analysis of stratospheric air.

By: Meis Uijttewaal, MSc EES student.

Summary:
The anthropogenic emissions of greenhouse gases do not only affect greenhouse gas concentrations in the troposphere, but also in the stratosphere. These enhanced levels of greenhouse gases affect the air flows in the stratosphere, which in turn influence the climate and weather in the troposphere. To improve climate change predictions, it is therefore important to monitor the levels of greenhouse gases in the stratosphere. The Lightweight Stratospheric Air Sampler enables relatively cheap and easy sampling of stratospheric air, as it can be launched on weather balloons. Part of its low weight is owed to the Multi-Layer Foil (MLF) bags in which the air samples are collected. In preliminary research on these bags, however, a drift in greenhouse gas concentrations was observed. In this thesis project the source of this drift has been further investigated. This was done by determining the accuracy with which the MLF bags can be filled with CO₂, CH₄ and CO and by studying the diffusion of CO₂, CH₄, CO and H₂O through the bags’ material. Furthermore, the suitability of the MLF bags for studying stratospheric stable isotope ratios was determined.