How Dual Polarization Technique May Improve Weather Radar on Commercial Aircraft 2019-01-1982
The airborne weather radar on a commercial aircraft is essential to ensure flight safety. It is able to detect severe weather, probable areas where presence of hail may be suspected, and thanks to its Doppler capability, the wind shears that may be dangerous when landing. However, because it operates at X-band, the picture that it offers to the pilot may be seriously biased in situation of severe weather, in reason of the attenuation of the radar wave.
The adoption of the dual pol technique in this weather radar would be most beneficial for the quality of the information delivered to the pilot for the following reasons:
1- Dual pol technique allows to operate a classification of the precipitation: distinguishing rain, melting layer, snow, hail, small ice particles.
2- Dual pol technique allows correcting the return signal for attenuation in rain.
The paper aims to report recent advances in the exploitation of dual pol data, based of the concept of normalisation of the particle size distribution (PSD) and on ZPHI® algorithm for precipitation retrieval. Their combination helps retrieving parameter N0* able to represent alone the variability of the PSD, for rain or ice particles whatever. The main interest of dual pol radar/ZPHI® software for inflight application is:
- To be able to calibrate the radar using self-consistency of polarimetric variables;
- To be able to measure ice concentration in altitude by implementing a new version of ZPHI® describing the along beam N0* evolution, on order to interpret le radar reflectivity in terms of ice concentration.
Jacques Victor TESTUD, Emmanuel MOREAU PhD, Erwan Le Bouar PhD
International Conference on Icing of Aircraft, Engines, and Structures