1. IRCTR: International Research Centre for Telecommunications and Radar Evaluation of particle shape and orientation within ice clouds using the S-band Doppler Polarimetric radar Tara – supersite H. COPS workshop – October 28th Y.Dufournet, H. Russchenberg

2.  Radar Tara : characteristics transmitterreceiver HHVV -FMCW S-band radar (3.3 GHz) - Doppler and Polarimetric capabilities : vertical and horizontal reception and transmission performed in sequences Ice and mixed-phase cloud measurement + precipitation measurement Wind mode - antennas: 75 degrees - Polarimetry: VV VH HH OB1 OB2 (3 beams) - time res.: ~ 3 s - min range res.: 15 m - max altitude: ~13 km microphysical mode - antennas: 45 degrees - Polarimetry: VV VH HH (1 beam) - time res.: ~ 3 s - min range res.: 15 m - max altitude: ~ 7 km

3.  Tara within COPS airport ( www.cops2007.de ) Period: July and August Placed in Hornisgrinde 264 measurements (310 hours of raw data) Orientation: 116 ° N (towards ARM site) measurements mode : mainly wind mode + 8 days in microphysical mode Radar direction

4.  Microphysic and radar measurements ? 0 velocity Spectral reflectivity Spectral polarimetric measurements particle orientation particle shape PSD (obtain from a microphysical model, not discussed in this presentation) Microphysical characteristics of ice particles:

5.  10 1112 14161513   Mono-modal Bi-modal sZdr categorization  Built using large data set Mono-modal Bi-modal category num > 10 Horizontal alignment Category numb < 9 Vertical alignment Category numb = 0  Not classified Category numb = -2  Not good enough sLDR < - 15 dB sρ > 0.97 sZvv > -20 dBZ 0 0 0 0 0 0 0 0 0

6.  1 st case: 21/07/07 (SOP 2 – EUFAR related) Boundary layer echo drizzle Melting layer rainfall Ice and mixed- phase cloud Frontal activities and mesoscale convective system development Horizontal alignment Vertical alignment Not classified sZdr simplified categorization

7.  21/07 – statistical interpretation (whole box) Mostly horizontally aligned particles Not classified (aggregates) Plates and dentrites formation region Hypothesis: presence of aggregates and plates or dentrites with preferred horizontal alignment Category number

8.  21/07 : vertical cloud structure From 2D-C probe (ATR42) www.safire.frwww.safire.fr and www.eufar.netwww.eufar.net From the radar (sZdr) velocity sZdr monomodal plates bimodal plates aggregates alone Riming and diffusional growth aggregation

9.  2 nd case: 11/07/07 Mean particle velocity (m.s -1 )  Showers events Doppler width (m.s -1 ) A lot of turbulence  processing not optimum yet

10.  11/07 – statistical interpretation (whole box) Columns formation region Mostly vertically aligned particles Not classified (aggregates) Hypothesis: presence of aggregates and columns with preferred vertical alignment Category number

11.  Conclusion This new retrieval of particle shape and orientation seems feasible within ice and mixed-phase clouds but more study has to be carry out 8 days will be processed within COPS using such technique: -27/06- 11/07 -21/07- 09/08 -17/08- 21/08 & 22/08 -28/08