1. Lidar difficulties, retrievals, and successes
Franco Marenco

2. The 146 lidar story Mevex (2009) – first use – qualitative
Laser frozen – six months for servicing
First version of on-board viewer (Lidardisplay)
Volcanic ash (2010) – quantitative – fully analysed
FENNEC (Apr+May 2011) – quantitative data analysis planned
Sept 2011 – loss of power – 4 months servicing
DIAMET (Nov-Dec 2011) – Manchester instrument – was poor → servicing
PIK&MIX (Jan-Feb 2012) – loan lidar from Leosphere (weak)
MEVALI (March 2012) – lidar back from Leosphere – weaker signal
April 2012 – tested in the lab for T dependence – no result
Water spill preventers + lidar breather installed
FENNEC (June 2012) – quantitative data analysis planned
July 2012 – laser broken – “self fix” (new laser) – good and strong signal
SAMBBA (Sept-Oct 2012) - quantitative data analysis planned
ALS450 out of production

3. Temperature effect
Ground-based
In flight

4. iButtons: temperature effect proven
RED – ground based
GREEN – COALESC
BLUE - FENNEC
Rayleigh scattering
constant (m= )

5. iButtons for housekeeping
To what temperature cycle
are we exposing the lidar?
Something happened on
Thursday, 29 September
2011 at 15:45!

6. Lidar upgrade In collaboration with Patrick Chazette (LSCE)
New “better” polarising beam splitters
Paris, January ?

7. Finding molecular layers: is the contour plot adequate?
Is this blue (low signal) due to
aerosols or Rayleigh scattering?
Fennec

8. Finding molecular layers: is the contour plot adequate?
aerosols or
alignment problem?
this slope is very
different from
Rayleigh scattering:
must be aerosols!!

9. Inversion of lidar signals
Range corrected signal
Aerosol extinction coefficient 1 2 3 4 5
Reference
Height 1
Height 2
backscatter
extinction
LIDAR
RATIO

10. Setting layers manually for analysis
accept/reject
surface spike
aerosol and depol
calibration ranges
cloud tops
ch0: yellow
ch1: brown

11. Volcanic ash: extinction coefficient retrievals
spatially resolved detection
~ 30% uncertainty
quantitative
signal
inversion
17 May
lidar ratio 60 sr
~1800 lidar profiles inspected + analysed (6 flights)

12. Ash concentration estimates
courtesy of B. Johnson,
J. Dorsey and M. Gallagher
Date fc
Kext
(m2/g)
4 May
0.52
0.92
5 May
0.72
0.65
14 May
0.97
0.62
16 May
0.78
0.82
17 May
18 May
0.75
0.74
Uncertainty:
~ factor of 2

13. Volcanic ash Lidar vs. NAME
courtesy of H. Webster
(Atmospheric Dispersion Group)
Volcanic ash Lidar vs. NAME
reasonable overall magnitude
positional errors sometimes
model uncertainties: source term, meteorology, sub-scale processes

14. Volcanic ash - Lidar vs. SEVIRI
courtesy of P. Francis and
M. Cooke (Satellite Applications)
17 May

15. ACEMED: validation of CALIPSO
In collaboration with V. Amiridis, A. Tsekeri and E. Marinou
(National Observatory of Athens)

16. In collaboration with H. Jones (U. Manchester)
COSIC: contrails
In collaboration with H. Jones (U. Manchester)

17. Verification of cirrus model
Courtesy of A. Baran

18. SAMBBA

19. SAMBBA

20. FENNEC

21. Questions and answers