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A Stereo Camera Simulator for Large-Eddy Simulations of Continental Shallow Cumulus clouds based on three-dimensional Path-Tracing
  • Yannick Rainer Burchart,
  • Christoph Beekmans,
  • Roel Neggers
Yannick Rainer Burchart
University of Cologne

Corresponding Author:[email protected]

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Christoph Beekmans
University of Bonn
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Roel Neggers
University of Cologne
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Abstract

The complex spatial and temporal structure of cumulus clouds complicates their representation in weather and climate models. Classic meteorological instrumentation struggles to fully capture these features. Networks of multiple high-resolution hemispheric cameras are increasingly used to fill this data gap, and provide information on this missing multi-dimensional spatial information. In this study, a path-tracing algorithm is used to generate virtual camera images of resolved clouds in Large-Eddy Simulations (LES). These images are then used as a camera network simulator, allowing reconstructions of three-dimensional cloud edges from the model output. Because the actual LES cloud field is fully-known, the combined path-tracing and reconstruction method can be statistically analyzed. The method is applied to LES realizations of summertime shallow cumulus at the Jülich Observatory for Cloud Evolution (JOYCE), Germany, which also routinely operates a camera network. We find that the Blender path-tracing method allows accurate reconstruction of up to 70% of the visible cloud edges, depending on camera distance and accuracy thresholds. Additionally, we conducted sensitivity tests and find that our method remains consistent and independent of changes in its hyperparameters. The sensitivity of the stereo reconstruction algorithm to cloud optical thickness is investigated, finding a cloud boundary placement error of approximately 182 m. This error can be considered typical for cloud boundary reconstruction using stereo camera imagery in general. The results provide proof of principle for future use of the method for evaluating LES clouds against real camera imagery, and for further optimizing the configuration of such camera networks.
15 Jun 2023Submitted to ESS Open Archive
23 Jun 2023Published in ESS Open Archive