Validation of the nocturnal boundary layer technique

Instruments to monitor the profiles of carbon dioxide and the flowfield were used to investigate different atmospheric features in relation to gas accumulation.

In our effort to create protocols and regulations targeted at minimizing the rate of increase of global warming, we must keep in mind the uncertainties that surround our best estimates of greenhouse gas (GHG) emissions. While most micrometeorological measurement techniques are only suitable for windy conditions, the Nocturnal Boundary Layer Technique can be used to measure trace gas flux during calm clear nights as the nighttime stability enables gas emitted at the ground to accumulate. The difference between two measurements over the depth of this layer is believed to integrate emissions from a large area representative of, in our case, an agricultural farm. In this presentation, we will discuss events of the NBL that have an impact on nocturnal gas accumulation near the surface. The NBL technique is an interesting approach to GHG measurement because it averages spatial variability and provides an estimate of trace gas flux at the farm scale. However, more exploration of associated phenomena is essential to determine the level of confidence in the results.