1. Institute of Atmospheric Physic
Differential Absorption Lidar to Measure Tropospheric Ozone Variations
Shi Kuang1, Mike Newchurch1, John Burris2, Steve Johnson3
1University of Alabama in Huntsville
2NASA-Goddard Space Flight Center
3NASA-Marshall Space Flight Center
Institute of Atmospheric Physic
Beijing, China
30 August 2010

2. Institute of Atmospheric physic
Outline
Introduction
Lidar hardware
Measurement examples
Future design
Conclusion
Institute of Atmospheric physic
Beijing, China , August 2010

3. Institute of Atmospheric physic
Introduction
The common techniques to measure ozone profile:
ozonesonde
satellite
lidar.
NOAA, NASA, United Nations Environment Programme, WMO, “Scientific Assessment of Ozone Depletion: 2002”.
Institute of Atmospheric physic
Beijing, China , August 2010

4. Institute of Atmospheric physic
Introduction
Ozonesonde
Measuring O3 up to 35km
~5m/s rising rate,
±10% uncertainty,
100-m vertical resolution
Strength: well-characterized, low up-front cost, good vertical resolution, OK for cloudy sky, simultaneous T/P/RH.
Weakness: long preparation time, drifting with wind.
UAHuntsville 2010 earth day launch
Institute of Atmospheric physic
Beijing, China , August 2010

5. 11-year and >600 ozonesonde profiles at Huntsville, AL, U.S.A.
Introduction
Ozonesonde
O3 mixing ratio (top) and RH (bottom)
11-year and >600 ozonesonde profiles at Huntsville, AL, U.S.A.
Institute of Atmospheric physic
Beijing, China , August 2010

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Introduction
Satellite
Strength: good for column O3, global distribution
Weakness: low vertical resolution (several km), cloud contamination
Liu et al. 2005
Institute of Atmospheric physic
Beijing, China , August 2010

7. Institute of Atmospheric physic
Introduction
Lidar
ground-based, aircraft-based, mobile
Strength: continuous measurement, high temporal resolution
Weakness: cloud contamination, expensive, can’t measure surface for ground-based
JPL-Table Mountain Facility
Institute of Atmospheric physic
Beijing, China , August 2010

8. Motivation of O3 lidar measurement
Introduction
Motivation of O3 lidar measurement
Provide high-resolution ozone observation needed by atmospheric modeling, satellite validation, and air quality studies.
Institute of Atmospheric physic
Beijing, China , August 2010

9. DIff. absorption lidar (DIAL) concept
Introduction
DIff. absorption lidar (DIAL) concept
Backscattering
Medium
O3 DIAL Equation R σ P R
R1 R2 On
Off λ
λon
λoff Δσ
Laser
Telescope
Institute of Atmospheric physic
Beijing, China , August 2010

10. Institute of Atmospheric physic
Lidar hardware
Typical composition
Transmitter (266, , 308, 316, 351, 355nm for O3)
Receiver (telescope and aft optics)
Detector (photomutiplier (PMT) or avalanche photodiode (APD))
Signal processing (photoncounting or analog) 10
Institute of Atmospheric physic
Beijing, China , August 2010

11. Institute of Atmospheric physic
Lidar hardware
Huntsville lidar
30Hz, 6 or 3mJ/pulse
285
291
16” Telescope
4” Telescope
Measurement range 3
Web server 2 1
Aft Optics
Computer 4
Nd:YAG pumped Dye laser
PMT 5
Licel
Nd:YAG pumped Dye laser
RAPCD-DIAL configuration 11
Institute of Atmospheric physic
Beijing, China , August 2010

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Introduction
Lidar lab setup
Institute of Atmospheric physic
Beijing, China , August 2010

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Lidar hardware
Transmitter
Pump
Dye laser
Institute of Atmospheric physic
Beijing, China , August 2010

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Lidar hardware
Receiver and detector
PMT
16’’ Newtonian telescope
4’’ customized small telescope
Institute of Atmospheric physic
Beijing, China , August 2010

15. Institute of Atmospheric physic
Measurement examples
1. Intense STE (~500ppbv at 7km) to reach top of the PBL (~2km) within 48 hours
500ppbv
Cloud
Cloud
Cloud
sonde
Ozone lidar measurements with a 10-min temporal resolution and ~500-m vertical range resolution from 27 to 28 April 2010.
Institute of Atmospheric physic
Beijing, China , August 2010

16. Co-located ozonesonde measurements
Measurement examples
Co-located ozonesonde measurements
Apr. 23, 2010
Apr. 27, 2010
May
Tropopause
Dry stratospheric air
Institute of Atmospheric physic
Beijing, China , August 2010

17. Institute of Atmospheric physic
Measurement examples
2. PBL O3 maximum
May 7
May 3, 2010
May 4, 2010
EPA surface O3
Sonde, 11:30
May 6 (high PBL O3)
May 5
89ppbv, highest during 2010 so far
Alt (km)
Local time
Aloft ozone in the PBL generally explains the daily surface maximum value although large differences between the surface and upper-air O3 often exist especially during nighttime.
Institute of Atmospheric physic
Beijing, China , August 2010

18. The 3rd Asia Pacific Radiation Symposium
Lidar observation, Aug. 4, 2010
Convolution of lidar ozone measurements between the surface and 10 km altitude at Huntsville, AL during August 4, 2010 with OMI ozone averaging kernel and a priori indicates that OMI is unable to capture the highly variable ozone structure in PBL, but captures a significant portion of the mid-tropospheric layer
Lidar convolved with OMI kernel
Convolution of lidar ozone measurements between the surface and 10 km altitude at Huntsville, AL during August 4, 2010 with OMI ozone averaging kernel and a priori indicates that OMI is unable to capture the highly variable ozone structure in PBL because of its resolution limitation
The 3rd Asia Pacific Radiation Symposium
Seoul, South Korea
25-28 August 2010
Hey!! 18

19. Institute of Atmospheric physic
Future plan
shift one dye laser to 316 and add two Raman-shifted lasers at 289 and 299 so that we can extend the observations to upper troposphere.
Apply dual-DIAL (289/299, 299/316) retrieval technique to further reduce aerosol interference in the lower troposphere.
Schematic diagram of the future transmitters, wavelength pairs, and their measurement ranges.
Institute of Atmospheric physic
Beijing, China , August 2010

20. Institute of Atmospheric physics
Future plan
3-λ dual DIAL technique
[Kovalev and Bristow 1996, Wang et al. 1997]
Dial Eqn.
On1-off1 +
On2-off2
-Cx
Dual-DIAL Eqn.
No assumption for lidar ratio and Angstrom!
Institute of Atmospheric physics
Beijing, China , August 2010

21. Raman cell for future transmitter
Future plan
Raman cell for future transmitter
Big Sky (Quantel) 266 pump laser
Raman gas cell
2-m Raman cell for future transmitter (289/299nm)
Institute of Atmospheric physics
Beijing, China , August 2010

22. Future receiving system for the wavelength
Future plan
Future receiving system for the wavelength
Institute of Atmospheric physic
Beijing, China , August 2010

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Conclusions
1. Lidar measures high spatio-temporal ozone variations associated with different dynamic and photochemical processes from PBL to upper troposphere.
2. The ozone variations and structures sometimes are closely correlated with aerosol and sometimes not.
3. Nocturnal residual ozone layers often exist decoupled from the surface.
4. The lidar observations will be very helpful for addressing the ozone variability captured by geostationary satellites and forecast with regional air-quality forecasts.
Institute of Atmospheric physic
Beijing, China , August 2010

24. Institute of Atmospheric physic
References
Kuang, S., et al. (2010), Differential Absorption Lidar (DIAL) to measure sub-hourly variation of tropospheric ozone profiles, IEEE Trans. Geosci. Remote Sens., in press.
Liu, X., K. Chance, C. E. Sioris, R. J. D. Spurr, T. P. Kurosu, R. V. Martin, and M. J. Newchurch, "Ozone profile and tropospheric ozone retrievals from Global Ozone Monitoring Experiment: Algorithm description and validation," J. Geophys. Res., 110, p. D20307, 2005.
NOAA, NASA, United Nations Environment Programme, WMO, “Scientific Assessment of Ozone Depletion: 2002”, World Meteorological Organization Global Ozone Research and Monitoring Project - Report No. 47
Institute of Atmospheric physic
Beijing, China , August 2010