Abstract. We demonstrate how machine learning can be easily applied
to support the analysis of large quantities of excited hydroxyl (OH*) airglow imager data. We use
a TCN (temporal convolutional network) classification algorithm to
automatically pre-sort images into the three categories “dynamic” (images
where small-scale motions like turbulence are likely to be found), “calm”
(clear-sky images with weak airglow variations) and “cloudy” (cloudy images
where no airglow analyses can be performed). The proposed approach is
demonstrated using image data of FAIM 3 (Fast Airglow IMager), acquired at
Oberpfaffenhofen, Germany, between 11 June 2019 and 25 February 2020,
achieving a mean average precision of 0.82 in image classification. The
attached video sequence demonstrates the classification abilities of the
learned TCN. Within the dynamic category, we find a subset of 13 episodes of image
series showing turbulence. As FAIM 3 exhibits a high spatial
(23 m per pixel) and temporal (2.8 s per image) resolution, turbulence
parameters can be derived to estimate the energy diffusion rate. Similarly to
the results the authors found for another FAIM station (Sedlak et al.,
2021), the values of the energy dissipation rate range from 0.03 to
3.18 W kg−1.