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CSIP & COPS workshop 2009 Tuesday, October 27 th

Ice crystals properties retrieval within ice and mixed-phase clouds using the Doppler polarimetric radar TARA. Y. Dufournet , C.M.H Unal, S. Placidi H.W.J Russchenberg. CSIP & COPS workshop 2009 Tuesday, October 27 th. transmitter. receiver. COPS status – TU Delft. FMCW radar TARA. V.

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CSIP & COPS workshop 2009 Tuesday, October 27 th

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  1. Ice crystals properties retrieval within ice and mixed-phase cloudsusing the Doppler polarimetric radar TARA. Y. Dufournet , C.M.H Unal, S. Placidi H.W.J Russchenberg CSIP & COPS workshop 2009 Tuesday, October 27th

  2. transmitter receiver COPS status – TU Delft • FMCW radar TARA V H V H • Located on Supersite H (Hornisgrinde) • measurements performed within:  ice or mixed-phase cloud (only the ice phase)  Precipitation 12 m TARA (3.3 GHz – 10 cm) • Outlines :  Cloud microphysical Retrieval principle  Case study and main use of COPS facilities

  3. Spectral polarimetric parameter - Principle Spectral reflectivity velocity 0 Particles with different size, habit, orientation ≠ fall velocities, particle axis ratio Doppler effect Polarimetric behavior Spectral polarimetric parameters Isolate different group of particles + radar

  4. Microphysical retrieval : resulting parameters Doppler information Retrieved Parameters •  Numb. of particles types • Particle orientation • Particle habits Forward model •  PSD for each particle type • radial wind, spectral broadening Radar cell height Assumption based time Polarimetric information Detailed microphysical analysis

  5. Measurement at a microphysical mode– 21/07/07  Based on a retrieval technique ! Retrieval zone Ice or mixed-phase cloud Melting layer Boundary layer top height Precipitation Drizzle time

  6. Retrieval orientation and particle habit Vertically aligned plates (+ dendrites) and few aggregates Horizontally aligned plates (+ dendrites) and few aggregates plates dendrites Mainly horizontal habits Mainly vertical Mainly aggregates and few plates Strong aggregation No orientation orientation No data

  7. Comparison particle habits Plate production region  Radiosonde launch Cloud top region  ATR 42 flight PMS 2D-C probes images

  8. D0 agg. Retrieval PSD and ambient wind D0 pla. Obtained from modified gamma distribution Vertical ambiant wind v0 Nt pla. Convergence zone Nt agg. Wind shear

  9. Comparison PSD ATR 42 retrieved Good agreement IWC Nt

  10. Cloud processes – possible explanation Mean vertical Doppler velocity from TARA Pristine ice prod. aggregation blocking area Plates fully blocked Only agg. precipitate vTARA = vparticles Orographic enhancement Strong updraft m.s-1

  11. Conclusion • Main achievements using COPS data set • microphysical retrieval: promising results on the cloud observation processes  assumptions tested and improved leading to good agreements when compared with other instruments • 3D wind measurements: corrected and assessed with radiosondes measurements  within optically thick clouds and precipitation What is next ? - Processing the remaining days - Full Assessment and validation of the microphysical retrieval

  12. Model Atmosphere Forward Models Synthetic observations EarthCARE SIMulator - ECSIM Earth Cloud Aerosols Radiaton Explorer by ESA Launch date: 2013 EarthCARE mission end2end SIMulator – ECSIM Simulate all the 4 EarthCARE instruments and the satellite platform • cloud scene creation ( PSD, reff, shape parameter, surface properties, cloud/aerosol information…) • input from LES models, fractal cloud generator • Space-borne radar and lidar • Ground-based / aircraft radar and lidar • Satellite imager and broadband radiometer (Courtesy of Simone Placidi)

  13. Simulated 94 GHz Radar Reflectivity (ground)‏ Validation – assessment with ECSIM Synthetic observations Optical Depth of original scene Microphysical data retrieved Comparison with COPS instrumentation (Courtesy of Simone Placidi)

  14. Thank you!

  15. Example horizontal particle motion (COPS) Observation of 3D particle motion at high resolution within ice/mixed-phase clouds and precipitation Wind shear at 4000 m 10 days processed 21 min averaged (Courtesy Christine Unal)

  16. EarthCARE SIMulator SIMULATIONS OUTPUT INPUT • Cloud scene • Scene dimensions • Atmospheric properties • Surface properties • Clouds/aerosols info • Scattering regions • ext, LWC, Reff • Gamma / log-normal distribution • shape parameter • min/max value of Reff for DSD • From LES, CRM, fractal cloud generator • Forward/Instruments models • ground • Radar (5GHz, 32Ghz, 94 GHz) • Lidar (0.353 nm) • Space: • Radar • Lidar • Multi Spectral Imager • Broadband radiometer • Outputs • Radar Reflectivity • Lidar return/ extinction/ backscatter • COT - Reff – LWP • Fluxes

  17. Radar measurement from TARA transmitter receiver • Doppler and Polarimetric capabilities: - transmit and receive horizontally (H) or vertically (V) change of the polarization state every 1ms: HH HV VV • Antennas at 45°  improve the polarimetric contrast V H V H Spectral polarimetric parameter 12 m TARA: Transportable Atmospheric RAdar (FMCW – S band) • Other requirements for cloud observation: • High resolution  15 m range resolution  1 profile every 1.5 s - For mixed-phase clouds : at 3.3 Ghz, reflectivity of supercooled water droplets below the noise level – direct measurement of the ice crystals!

  18. Case study – 21/07/2007 (COPS – EUFAR) Convective and Orographically-induced Precipitation Study Meteorological situation: Frontal activities and mesoscale convective system development with orographic inhancement France Hornisgrinde Black Forest Retrieval zone Ice or mixed-phase cloud Melting layer Boundary layer top Precipitation Drizzle

  19. Measurement type overview •  Numb. of particles types • Particle orientation • Particle habits Microphysical model  Simulated sZDR(v) + sZHH(v) Doppler information Least square fit algorithm Cloud microphysical retrieval Radar cell height •  PSD for each particle type • radial wind, spectral broadening Assumption based time Velocity Signal improvement Polarimetric information Mean Doppler velocity Doppler width  Particle motion

  20. Type of measurements Microphysical mode : retrieval Doppler information •  Numb. of particles types • Particle orientation • Particle habits •  PSD for each particle type • radial wind, spectral broadening Assumption based Radar cell height Wind mode : moment computation from 3 beams Mean Doppler velocity Doppler width time Particle fall velocity, horizontal wind speed and direction Polarimetric information

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