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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Ice crystals properties retrieval within ice and mixed-phase clouds using the Doppler polarimetric radar TARA. CSIP & COPS workshop 2009 Tuesday, October 27 th Y. Dufournet, C.M.H Unal, S. Placidi H.W.J Russchenberg
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 2 COPS status – TU Delft Outlines : Cloud microphysical Retrieval principle Case study and main use of COPS facilities transmitterreceiver HHVV TARA 12 m FMCW radar TARA - Located on Supersite H (Hornisgrinde) - measurements performed within: ice or mixed-phase cloud (only the ice phase) Precipitation (3.3 GHz – 10 cm)
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 3 Spectral polarimetric parameter - Principle Particles with different size, habit, orientation ≠ fall velocities, particle axis ratio 0 velocity Spectral reflectivity Doppler effect Polarimetric behavior radar + Spectral polarimetric parameters Isolate different group of particles
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 4 Microphysical retrieval : resulting parameters height time Polarimetric information Doppler information Radar cell Numb. of particles types Particle orientation Particle habits PSD for each particle type radial wind, spectral broadening Assumption based Retrieved Parameters Forward model Detailed microphysical analysis
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 5 Measurement at a microphysical mode– 21/07/07 Precipitation Ice or mixed- phase cloud Melting layer Drizzle Boundary layer top Retrieval zone time height Based on a retrieval technique !
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 6 Retrieval orientation and particle habit plates dendrites Mainly horizontal Mainly vertical No orientation No data Horizontally aligned plates (+ dendrites) and few aggregates Vertically aligned plates (+ dendrites) and few aggregates Strong aggregation Mainly aggregates and few plates orientation habits
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 7 Comparison particle habits Radiosonde launch ATR 42 flight Plate production region Cloud top region PMS 2D-C probes images
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 8 Retrieval PSD and ambient wind D0 agg. D0 pla. Nt agg. Nt pla. Vertical ambiant wind Obtained from modified gamma distribution Wind shear Convergence zone v0v0
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 9 Comparison PSD ATR 42 retrieved IWC Nt Good agreement
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 10 Cloud processes – possible explanation m.s -1 Mean vertical Doppler velocity from TARA Pristine ice prod. aggregation Orographic enhancement Strong updraft blocking area Only agg. precipitate Plates fully blocked v TARA = v particles
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 11 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 Conclusion What is next ? - Processing the remaining days - Full Assessment and validation of the microphysical retrieval
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 12 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 Model Atmosphere Model Atmosphere Forward Models Synthetic observations Synthetic observations Space-borne radar and lidar Ground-based / aircraft radar and lidar Satellite imager and broadband radiometer (Courtesy of Simone Placidi) cloud scene creation ( PSD, r eff, shape parameter, surface properties, cloud/aerosol information…) input from LES models, fractal cloud generator
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 13 Validation – assessment with ECSIM Microphysical data retrieved Comparison with COPS instrumentation (Courtesy of Simone Placidi) Optical Depth of original scene Simulated 94 GHz Radar Reflectivity (ground) Synthetic observations
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 14 Thank you!
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 15 Example horizontal particle motion (COPS) Wind shear at 4000 m 10 days processed (Courtesy Christine Unal) 21 min averaged Observation of 3D particle motion at high resolution within ice/mixed-phase clouds and precipitation
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 16 EarthCARE SIMulator INPUT OUTPUTSIMULATIONS 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 Outputs - Radar Reflectivity - Lidar return/ extinction/ backscatter - COT - Reff – LWP - Fluxes Forward/Instruments models - ground - Radar (5GHz, 32Ghz, 94 GHz) - Lidar (0.353 nm) - Space: - Radar - Lidar - Multi Spectral Imager - Broadband radiometer
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 17 Radar measurement from TARA transmitterreceiver HHVV 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 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! TARA: Transportable Atmospheric RAdar (FMCW – S band) 12 m Spectral polarimetric parameter
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 18 Case study – 21/07/2007 (COPS – EUFAR) France Convective and Orographically-induced Precipitation Study Precipitation Ice or mixed- phase cloud Melting layer Drizzle Meteorological situation: Frontal activities and mesoscale convective system development with orographic inhancement Boundary layer top Retrieval zone Hornisgrinde Black Forest
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 19 Measurement type overview height time Polarimetric information Doppler information Radar cell Microphysical model Simulated sZ DR (v) + sZ HH (v) Numb. of particles types Particle orientation Particle habits Least square fit algorithm Signal improvement PSD for each particle type radial wind, spectral broadening Velocity Assumption based Particle motion Cloud microphysical retrieval Mean Doppler velocity Doppler width
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IRCTR - International Research Centre for Telecommunication and Radar ATMOS Delft University of Technology 20 Type of measurements height time Polarimetric information Doppler information Radar cell Numb. of particles types Particle orientation Particle habits PSD for each particle type radial wind, spectral broadening Assumption based Wind mode : moment computation from 3 beams Microphysical mode : retrieval Mean Doppler velocity Doppler width Particle fall velocity, horizontal wind speed and direction
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