This page contains interactive HTML figures from the paper Vertical Coherence of Volumetric Radar Motion Fields and Its Implications for Precipitation Nowcasting.
Estimating motion from spatiotemporal geoscientific data is a fundamental component of many environmental modeling and forecasting tasks. This work investigates whether estimating multiple altitude-wise horizontal motion fields from volumetric weather radar observations provides utility beyond existing two-dimensional approaches. We propose a physics-informed deep learning framework for estimating altitude-wise motion fields directly from volumetric radar reflectivity data, enabling efficient inference of horizontal motion across multiple altitude levels. Using a multi-year radar dataset from Central Europe, we evaluate the impact of altitude-wise motion estimation on extrapolation-based precipitation nowcasting and conduct a systematic dataset-scale analysis of inter-altitude motion consistency. The results show that the estimated motion fields exhibit strong vertical coherence, resulting in only limited improvement over traditional two-dimensional approaches. Our findings show that a more physically faithful three-dimensional representation does not necessarily yield greater predictive value and the utility of volumetric motion modeling should be established from the characteristics of the underlying observations rather than assumed in advance.
Preprint link: https://arxiv.org/pdf/2603.13589
Vertically pooled CMAX representations of a severe precipitation event over Slovakia on July 5th 2022. The left image shows target radar observations and the right image the extrapolations obtained by advecting the final observation using the volumetric motion field estimated by the proposed 3D Motion Field U-Net. The estimated 3D motion field is vertically averaged and overlaid for reference. Zoomed regions highlight a non-physical cell-splitting artifact produced by the volumetric approach.
Estimated horizontal motion fields and corresponding precipitation fields for three events selected for their low inter-altitude motion correlation and high precipitation coverage. The All Vertical Slices animations show a horizontal slice through the motion field for all altitudes, averlaid with a corresponding reflectivity measurement. The In Motion Animations show the estimated horizontal motion fields and corresponding precipitation fields at the lowest altitude layer (500–1000 m above ground level; left) and a mid-level layer (2500–3000 m above ground level; right).
Figure 12 (a) All Vertical Slices
Figure 12 (b) All Vertical Slices