Turbulence Observations in Layered Clouds

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Turbulence Observations in Layered Clouds

• B. Albrecht and P. Kollias

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94 GHz (?3mm) Doppler Radar Observations

• Radar Characteristics
• ?z30 m ?t2-3 s ?v0.03ms-1
• Beam width0.25o
• Sensitivity -51 dBZ at 1 km
• Basic Processing (Doppler Spectrum Moments)
• Turbulence Processing
• Vertical velocity statistics
• Updraft-downdraft characteristics
• Mass-flux decomposition
• Radar sampling volume turb

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Doppler Spectrum Variance
S(k) is the turbulence spectrum k1 2p/L1 k2
2p/L2
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Continental Stratocumulus Cloud Reflectivity and
Doppler Velocities
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In-Cloud w Spectra Using 2-sec and Degraded
10-sec Data.
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Evolution of Turbulence Statistics in Continental
Stratus Clouds
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CRYSTAL-FACE Cirrus Anvil Observations
ETL-

• UM 94 GHz Doppler Cloud Radar (UM DCR)
• ETL 35 GHz Doppler Cloud Radar (ETL DCR)

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UM-94 ETL-35
UM-94 ETL-35
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Conclusions

• Turbulence mapping of both resolvable-scale and
  sub-radar volume turbulence demonstrated
• Applications
• Identify regions where spectral width can be used
  to retrieve cloud properties
• LES comparisons
• Estimate dissipation rates