5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
4th Symposium on Lidar Atmospheric Applications
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system
for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
Institute for Meteorology and Climate Research, KITKarlsruhe, Germany
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Contents
Horizontal wind– complementary profiles and
– identification of measurement errors
Vertical wind – in different atmospheric situations
– a new approach estimating rain-drop size-distributions
– complementary profiles of vertical velocity variance
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Instrumental and experimental setup
2 µm Doppler lidar
35.5 GHz cloud radar
Collocated on Hornisgrinde mountain (Black Forest) and performing a coordinated scan strategy from June to August 2007, COPS campaign
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Horizontal wind
lidarradar
Hypothesis: aerosol drifts with horizontal wind independent of it’s size
simultaneous measurements deliver same results
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Horizontal wind
Hypothesis: aerosol drifts with horizontal wind independent of it’s size
simultaneous measurements deliver same results
only lidar
both
only radar
no data
Increase of available information from 32% using only lidar to 51% using the combination.
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Horizontal wind
Hypothesis: aerosol drifts with horizontal wind independent of it’s size
simultaneous measurements deliver same results
only lidar
both
only radar
no data
0
10
20
30
40
50
60
70
<0.1 <1 <2 >5
mit ground clutter
ohne groundclutter
velocities differ by
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
0
10
20
30
40
50
60
70
<0.1 <1 <2 >5
mit ground clutter
ohne groundclutter
Horizontal wind
Hypothesis: aerosol drifts with horizontal wind independent of it’s size
simultaneous measurements deliver same results
Ground clutterproblem
velocities differ by
only lidar
both
only radar
no data
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Horizontal wind
Hypothesis: aerosol drifts with horizontal wind independent of it’s size
simultaneous measurements deliver same results
Ground clutterproblem
0
10
20
30
40
50
60
70
80
90
<0.1 <1 <2 >5
mit ground clutter
ohne groundclutter
involving ground clutterground clutter corrected
velocities differ by
only lidar
both
only radar
no data
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Vertical wind
Hypothesis: size dependent fall velocity of the larger aerosols and droplets
simultaneously measurements deliver different results due to different wavelengths of the instruments and so different scatter mechanism
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Vertical wind
Clear air day82.1% agree better than 0.5 ms-1
Hypothesis: size dependent fall velocity of the larger aerosols and droplets
simultaneously measurements deliver different results due to different wavelengths of the instruments and so different scatter mechanism
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Vertical wind
During rain
Mean difference of 3 ms-1
Hypothesis: size dependent fall velocity of the larger aerosols and droplets
simultaneously measurements deliver different results due to different wavelengths of the instruments and so different scatter mechanism
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Vertical wind during rain
Lidar double peaks
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Vertical wind during rain
Lidar double peaks
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Vertical wind during rain
Lidar double peaks
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Vertical wind during rain
Radar Rayleigh scattering
reflectivity proportional D6
Lidar optical scattering
backscatter proportional D2
Size dependent terminal fall velocity and γ distribution of rain-drop-size
Idea: Estimating rain drop size distribution from velocity difference
lidar
radar
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Power spectra and vertical wind variance
Is vertical velocity variance influenced by the differences of measured vertical velocity?
Clear air conditions Light rain conditions
Clouds ?
lidarradar
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Conclusions
• Increase of valid horizontal wind information• Little redundant measurements• Potential to detect measurement errors• Differences in vertical wind velocity due to terminal size
dependent fall velocities of scatterers• New approach to estimate rain drop size distribution from
different measured velocities• Clear air power spectra behave quite similar, potential to
extend profiles of vertical velocity variance into clouds
Measurement combination of a cloud radar and a Doppler lidar allows new measurement approaches.
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Thanks
Thanks for attention.
For details please see manuscript.
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Additionally information
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Instrument specifications
0.1 … 25° s-1Up to 10° s-1Scan velocity
-5 … 185°45 … 135°Elevation angle
0 … 360°-3 … 363°Azimuth angle
72 m30 mSpatial resolution
350 m150 mLowest range gate
100512Range gates
4.5 kW30 kWPeak power
100 MHz50 MHzSampling rate
± 20 ms-1± 10.6 ms-1Unambiguous velocity
500 Hz5 kHzPulse repetition frequency
425 ns200 nsPulse width
2023 nm8.44 mmwavelength
Wind lidarCloud radar
5.3 Advantages of a coordinated scanning Doppler lidar and cloud radar system for wind measurements
K. Träumner, J. Handwerker, A. Wieser, J. Grenzhäuser and C. Kottmeier
KIT – die Kooperation vonForschungszentrum Karlsruhe GmbHund Universität Karlsruhe (TH)
Effect ground clutter correction
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