AErosol%20Raman%20Ozone%20Lidar%20(AeROLidar) - PowerPoint PPT Presentation

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AErosol%20Raman%20Ozone%20Lidar%20(AeROLidar)

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Title: AErosol%20Raman%20Ozone%20Lidar%20(AeROLidar)


1
AErosol Raman Ozone Lidar(AeROLidar)
OZONE PROFILES FOR THE ARCIONS CAMPAIGN APRIL/JUL
Y 2008
  • Dr. Kevin Strawbridge
  • Bernard Firanski
  • Mike Harwood
  • Michael Travis
  • Kevin.strawbridge_at_ec.gc.ca
  • Bernard.firanski_at_ec.gc.ca

ENVIRONMENT CANADA Centre for Atmospheric
Research Experiments
2
Location
                      
                                                                            
  • Rural Ontario site

3
Instrument Introduction
  • Dual wavelength single transmitter developed by
    Masahisa Nakazato (Met. Res. Inst., Japan)
  • CO2 Raman scattering of 266 nm
  • 287 (on) 299 nm (off) pair in Hartley band
  • Initial configuration attempted double-pump
    Powerlites using a 2 m Raman cell
  • Same pressure used by Japanese
  • System is much more complicated than on paper!

4
Transmitters
  • Continuum Powerlite 9030
  • 266 nm at 100 mJ per pulse
  • 30 Hz
  • Continuum Inlite
  • 532 nm at 340 mJ per pulse
  • 30 Hz
  • CO2 Raman cell
  • 2 m long
  • 400-700 kPa pressure

5
Receivers
  • AERO Receiver
  • 90 cm Cassegrain Telescope
  • 287 299 Hamamatsu 7400 PMT pair
  • Licel Transient Digitizer
  • 1064, 607, 532 nm channels
  • 355, 387, 407 nm channels
  • Aerosol Lidar Receiver
  • 45 cm Cassegrain Telescope

6
DIAL Algorithm Testing
  • Simulated ozone profiles performed well w/o noise
  • Tested concentration algorithm on a real profile
  • Performed well even if missing aerosol
    characterization

7
Data Overview
  • April Period
  • Laser installed April 1
  • First week used for alignment and synching of
    double-pump Powerlites
  • Opted for single-pump
  • Operational April 10
  • First clear day April 15
  • Collected until April 21
  • Defective laser crystals hampered efforts
  • Typical data limit of 6km
  • July Period
  • Significant cloud cover
  • Used alternate Aerosol Lidar for 1064/532 nm
  • Data collection from June 28-July 10
  • Typical data limit of 8-10km
  • Defective laser crystals
  • Laser power instability

8
April Data
9
April Data
  • Atmosphere was hazy the first week
  • System not properly aligned
  • 299 nm signal returns weak compared to 287 nm
    returns

10
Aerosol Plots
2008-04-15
2008-04-16
2008-04-17
2008-04-18
11
Aerosol Plots
2008-04-19
2008-04-20
2008-04-21
12
Ozone Aerosol Correlation?
13
July data
14
July data
15
Ozonesonde Comparison
16
Aerosol Plots
2008-06-28
2008-06-29
2008-07-02
2008-07-04
17
Aerosol Plots
2008-07-05
2008-07-06
2008-07-07
2008-07-10
18
Aerosol Correlation
19
Aerosol Correlation
20
Ozone Dynamics
  • Apparent decrease in overall ozone content as
    evening progresses
  • Structure evident near 5 km and near 2 km
  • Ozone enhancement between 6-7 km around 1900 UTC?
  • Does not match the aerosol structure chemistry
    dominating dynamics?

21
Current Data
  • System alignment is far better
  • Laser power stability improved
  • Aerosol and DIAL systems now have common receiver

22
Summary
  • Brand new instrument used for very first time
    during April campaign
  • Significant improvement between April and July
  • System performed well in matching overall ozone
    trends after correction factor applied
  • Small-scale features do not match sonde, but
    sonde features varied even over a 4-hr span
  • Concurrent aerosol scans show little correlation
  • Dynamics are possible with the instrument

23
What Now?
  • Instrument Development
  • Continue investigating instrument performance
  • Expand wavelengths
  • Install a boundary layer telescope
  • Investigate proper extinction and scatter
    exponents
  • Include cloud screening
  • Research
  • Look for Boreal fire signatures
  • Examine back-trajectories
  • Examine MODIS aerosol swath data
  • FLEXPART?
  • AURAMS?

24
The End
  • Thank You!

25
Signal Simulation and Calibration
  • Calibration accomplished using model Lidar signal
    profile subject to actual ozone
  • 3rd order polynomial correction factor generated
    from ratio of actual vs model signal profile
  • Aerosols have minimal impact
  • Noise is problematic at upper altitudes
  • Calibration does well in correcting
    opti-mechanical effects w/o introducing features
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