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Analysis of the Composition of Clouds with Extended Polarization Techniques

Analysis of the Composition of Clouds with Extended Polarization Techniques. L. Pfitzenmaier, H. Russchenbergs group (TU Delft) TROPOS , Germany KNMI METEK, Germany. Motivation. Ice particle within mixed-phase clouds growth processes (L. Pfitzenmaier , TU Delft)

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Analysis of the Composition of Clouds with Extended Polarization Techniques

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  1. Analysis of the Composition of Clouds with Extended Polarization Techniques • L. Pfitzenmaier, H. Russchenbergsgroup(TU Delft) • TROPOS, Germany • KNMI • METEK, Germany

  2. Motivation • Ice particle within mixed-phase clouds • growth processes (L. Pfitzenmaier, TU Delft) • shape categorisation (A. Myagkov, TROPOS, Germany) • Why? • Process important for • precipitation formation • Gap betweentheory • and observations of • thoseprocesses/clouds • Improve mixed-phase cloud • observations • Measuring inCabauw < 0⁰C > 0⁰C

  3. Microphysical description of mixed-phase clouds Mixed phase clouds: Mid-level clouds (~3 – 7 km) -40 ⁰C < Temperature < 0⁰ • Super cooled cloud droplets • Shape: spherical • Phase: Liquid • Size: ~ 10 mm • High concentration • 100 – 1000 cm-3 Liquid phase & ice crystals • Ice crystals • Shape: not spherical • Pristine ice crystals • Aggregates • Graupel • Phase: solid • Size: mm – cm • Lower concentration • < 100 cm-3

  4. Microphysical description of mixed-phase clouds Mixed phase clouds: Mid-level clouds (~3 – 7 km) -40 ⁰C < Temperature < 0⁰ • Super cooled cloud droplets • Shape: spherical • Phase: Liquid • Size: ~ 10 mm • High concentration • 100 – 1000 cm-3 Liquid phase & ice crystals • Ice crystals • Shape: not spherical • Pristine ice crystals • Aggregates • Graupel • Phase: solid • Size: mm – cm • Lower concentration • < 100 cm-3 • Synergy of instruments to measure the whole cloud system

  5. Why Cabauw..? • Instrumentation at Cabauw: • TARA  ice phase & growth categorization processes • CAELI  liquid layer detection • Cloud radar  ice and liquid • Radiometer  liquid layer • Wind profiler  vertical dynamic (Doppler spectra?)

  6. Transportable Atmospheric Radar – TARA • S-band profiler: • f=3.298 GHz, l=9.09 cm (Rayleigh-scattering) • Fully polarimetric Shape/orientation of particles • Doppler capability  Velocity of hydrometeors • High temporal (> 3.5 s) and spatial resolution (> 3 m) • small scale processes • Sensitive to large hydrometeors (size) • Precipitation (drizzle, rain, snow, hail) • Ice crystals • NOT TO CLOUD DROPLETS (~10 mm) • Direct measurement of the ice phase • Use of a second instrumentto get information about the liquid phase

  7. CESAR cloud, aerosol, and water vapourliadr - CAELLI • 3 wavelength Raman lidar • 1064 nm, 532 nm, 355nm – • 2 Raman channels: 387 nm and 607 nm • Water vapor channel 407 nm • Depolarization channel 532 nm • extinction coefficient • backscatter coefficient • depolarization ratio • High special resolution (7.5 m) • Sensitive to small particles • Aersols • Cloud droplets • Information about liquid water layers within mixed phase clouds

  8. Measurement set up Cabauw Raman Lidar – CAELI • Sensitive to particle concentration Radar – TARA • Sensitive to particle size Donovan and Lammeren, 2001 Y. Dufournet PhD Thesis Microwave radiometer • Gives values of the liquid water path (LWP) • the amount of liquid water present in the cloud system • : extinction coefficient • n(r) : droplet number concentration • r : droplet radius • Z : reflectivity

  9. Why Cabauw..? • Instrumentation at Cabauw: • TARA  ice phase & growth categorization processes • CAELI  liquid layer detection • Cloud radar  ice and liquid • Radiometer  liquid layer • Wind profiler  vertical dynamic (Doppler spectra?) • LACROS (Leipzig Aerosol and Cloud Observations System) • More information on the liquid phase • Founded by ACTRIS-TNA and TROPOS More instruments needed

  10. Leipzig Aerosol and Cloud Observations System - LACROS Mira35 • Cloud radar – Mira 35 STAR mode  scanning • shape categorization of ice particles • scanning strategy • liquid phase information • Microwave radiometer • liquid phase information • Ceilometer  Cloud base • Distrometer Rain droplet sizes • Raman lidar – PollyXT (of zenith pointing) • liquid layer detection • runs automatically – 24/7 • Doppler lidar • analyze the dynamic at cloud base • Cloud radar – Mira35  vertical pointing • Comparison with other radars • Radiosounds • Aircraft...? Doppler-lidar Caeli TARA MWR LACROS

  11. Goals of ACCEPT • Categorization of the ice phase in mixed-phase clouds • characterize of ice particle growth processes • testing the Mira35 STAR mode radar • Comparison of radar measurements • comparison of particle shape measurements • TARA and Mira35-STAR mode • sensitivity studies • Cloud measurements with CAELI • compare with PollyXT measurements • Creating a data set where also other studies could be done • Open data base • More about scientific work  Poster

  12. date: 6-10 – 16-11-2014 • Information about campaign: • http://atmos.weblog.tudelft.nl • open data base • more radiosounds…? • Interested...? Contact us • l.pfitenmaier@tudelft.nl • y.dufournet@tudelft.nl TARA – S-band precipitation radar CAELI – Raman lidar Wind profiler Cloud radar - KNMI Mira35 – STAR mode cloud radar Mira35 – LDA mode cloud radar PollyXT – Raman lidar Doppler lidar Microwave radiometer Distrometer Ceilometer Radiosounds

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