International Research Centre for Telecommunications and Radar High resolution 3D wind profiling using an S-band polarimetric FM-CW radar: dealiasing techniques Christine Unal, Herman Russchenberg Delft University of Technology, The Netherlands Dmitri Moisseev Colorado State University, Fort Collins, CO, USA  Type of measurement  First main limitation: small Maximum Unambiguous Doppler velocity  Dealiasing techniques (polarimetric and classical)  Example of Wind retrieval results

International Research Centre for Telecommunications and Radar  Goal: Dynamics and Microphysics of Precipitation and Clouds  Sensor: Doppler polarimetric radar TARA (S-band)  High resolution in space (30-3 m) and time (1-10s)  Location: Atmospheric profiling site Cabauw (synergy with other sensors)

International Research Centre for Telecommunications and Radar Measurement configuration 3 beams  3 mean Doppler velocities  horizontal wind + vertical wind 15 o OB1 Y X MB OB o elevation vertical MB VV HV HH OB1 OB2 The max. unambiguous Doppler velocity is reduced by a factor 5 time

International Research Centre for Telecommunications and Radar Polarimetric de-aliasing Expected differential phase ~ 0 at S-band Measured differential phase: Measured Doppler speed Maximum unambiguous Doppler speed Non simultaneity of VV and HH measurements

International Research Centre for Telecommunications and Radar Main beam: polarimetric dealiasing technique  Expected differential phase ~ 0 at S-band  Measured differential phase shows different mean values in case of aliasing

International Research Centre for Telecommunications and Radar Main beam: polarimetric dealiasing technique

International Research Centre for Telecommunications and Radar Main beam: polarimetric dealiasing technique

International Research Centre for Telecommunications and Radar Profiles of mean Doppler velocities for the 3 beams Classical dealiasingPolarimetric dealiasing

International Research Centre for Telecommunications and Radar Resulting horizontal wind retrievals

International Research Centre for Telecommunications and Radar Conclusions  High resolution profiling of horizontal wind in precipitation and clouds example with time resolution = 5 s and range resolution = 30 m  What has still to be done Improved clutter suppression for non polarimetric beams Separation between fall velocities of hydrometeors and vertical wind Correction for effects of beam divergence (possible limitation for high altitudes clouds)  First Objectives Dynamics of the boundary layer. Preparation for study of cloud-aerosol interaction.

International Research Centre for Telecommunications and Radar Main beam: polarimetric dealiasing technique Applying the classification in 5 intervals, the Doppler spectra bins of targets with  co smaller than 0.78 are placed in the wrong interval of Doppler velocities Clutter and noise reduction

International Research Centre for Telecommunications and Radar Offset beam: classical dealiasing technique Precipitation event slant profile Aliased Doppler spectra Doppler velocity [m/s]

International Research Centre for Telecommunications and Radar Offset beam: classical dealiasing technique Resulting spectrograph with dealiasing + noise reduction Search for signal above noise level at Unfolding (using max. spectral reflectivity) Reference: Doppler spectrum of cloud Range continuity check with a cross correlation function