Estimation of Near Surface Wind Speeds in Strongly Rotating Flows

TL;DR

This paper presents a method to estimate near-surface wind speeds in tornadic vortices using Doppler radar data and velocity models, enabling extrapolation of wind information from higher altitudes to the surface.

Contribution

A novel methodology combining parametric velocity models and continuity constraints to infer surface wind speeds from radar measurements in tornadoes.

Findings

Information from above can be extrapolated to the surface layer.

Numerical tests demonstrate the method's effectiveness.

The approach improves understanding of near-surface tornado winds.

Abstract

Modeling studies consistently demonstrate that the most violent winds in tornadic vortices occur in the lowest tens of meters above the surface. These velocities are unobservable by radar platforms due to line of sight consider- ations. In this work, a methodology is developed which utilizes parametric tangential velocity models derived from Doppler radar measurements, to- gether with a tangential momentum and mass continuity constraint, to esti- mate the radial and vertical velocities in a steady axisymmetric frame. The main result is that information from observations aloft can be extrapolated into the surface layer of the vortex. The impact of the amount of information available to the retrieval is demonstrated through some numerical tests with pseudo-data.