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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, KIT Karlsruhe, Germany.

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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

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


Contents

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

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


Instrumental and experimental setup

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

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


Horizontal wind

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

Horizontal wind

Hypothesis: aerosol drifts with horizontal wind independent of it’s size

simultaneous measurements deliver same results

lidar

radar


Horizontal wind1
Horizontal wind cloud radar system

Hypothesis: aerosol drifts with horizontal wind independent of it’s size

simultaneous measurements deliver same results

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


Horizontal wind2
Horizontal wind cloud radar system

Hypothesis: aerosol drifts with horizontal wind independent of it’s size

simultaneous measurements deliver same results

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


Horizontal wind3
Horizontal wind cloud radar system

Hypothesis: aerosol drifts with horizontal wind independent of it’s size

simultaneous measurements deliver same results

Ground clutter

problem

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


Horizontal wind4

involving ground clutter cloud radar system

ground clutter corrected

velocities differ by

Horizontal wind

Hypothesis: aerosol drifts with horizontal wind independent of it’s size

simultaneous measurements deliver same results

Ground clutter

problem

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


Vertical wind

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

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


Vertical wind1

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

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

Clear air day

82.1% agree better than 0.5 ms-1


Vertical wind2

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

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

During rain

Mean difference

of 3 ms-1


Vertical wind during rain

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

Vertical wind during rain

Lidar double peaks


Vertical wind during rain1

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

Vertical wind during rain

Lidar double peaks


Vertical wind during rain2

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

Vertical wind during rain

Lidar double peaks


Vertical wind during rain3

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

Vertical wind during rain

Idea: Estimating rain drop size distribution from velocity difference

Radar Rayleigh scattering

reflectivity proportional D6

Lidar optical scattering

backscatter proportional D2

lidar

radar

Size dependent terminal fall velocity and

γdistribution of rain-drop-size


Power spectra and vertical wind 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

Power spectra and vertical wind variance

Is vertical velocity variance influenced by the differences of measured vertical velocity?

Clear air conditions

Light rain conditions

lidar

radar

Clouds ?


Conclusions

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

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.


Thanks

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

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

Additionally information


Instrument specifications
Instrument specifications cloud radar system

Cloud radar

Wind lidar

wavelength

8.44 mm

2023 nm

Pulse width

200 ns

425 ns

Pulse repetition frequency

5 kHz

500 Hz

Unambiguous velocity

± 10.6 ms-1

± 20 ms-1

Sampling rate

50 MHz

100 MHz

Peak power

30 kW

4.5 kW

Range gates

512

100

Lowest range gate

150 m

350 m

Spatial resolution

30 m

72 m

Azimuth angle

-3 … 363°

0 … 360°

Elevation angle

45 … 135°

-5 … 185°

Scan velocity

Up to 10° s-1

0.1 … 25° s-1

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


Effect ground clutter correction

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

Effect ground clutter correction


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