Advances in 3D scattering tomography of cloud micro-physics

TL;DR

This paper presents novel methods for 3D scattering tomography of clouds, improving the accuracy of retrieving liquid water content and droplet size by incorporating advanced polarization models and 3D variations.

Contribution

It introduces new adjustments including an advanced polarization model and 3D effective radius variation, enhancing retrieval accuracy over previous methods.

Findings

Smaller errors in micro-physical property retrievals compared to prior art.

Enhanced sensitivity to droplet micro-physics through polarization and single-scattering viewpoints.

Effective initialization and optimization strategies improve retrieval robustness.

Abstract

We introduce new adjustments and advances in space-borne 3D volumetric scattering-tomography of cloud micro-physics. The micro-physical properties retrieved are the liquid water content and effective radius within a cloud. New adjustments include an advanced perspective polarization imager model, and the assumption of 3D variation of the effective radius. Under these assumptions, we advanced the retrieval to yield results that (compared to the simulated ground-truth) have smaller errors than the prior art. Elements of our advancement include initialization by a parametric horizontally-uniform micro-physical model. The parameters of this initialization are determined by a grid search of the cost function. Furthermore, we added viewpoints corresponding to single-scattering angles, where polarization yields enhanced sensitivity to the droplet micro-physics (i.e., the cloudbow region). In addition, we introduce an optional adjustment, in which optimization of the liquid water content and effective radius are separated to alternating periods. The suggested initialization model and additional advances have been evaluated by retrieval of a set of large-eddy simulation clouds.