first results of the aerosol profiling group iup heidelberg bira-iasb mpic mainz iup bremen...
DESCRIPTION
CIMEL sunphotometer (TNO) → AOD at different wavelengths & ssalb, phase-function Nephelometer (PSI,TNO) → surface extinction & ssalb, phase-function Ramen LIDAR (RIVM) → aerosol extinction profiles Ceilometer (KNMI) → boundary layer height Backscatter lidar (RIVM) → boundary layer height The participants: …TRANSCRIPT
First results of the aerosol profiling group
IUP HeidelbergBIRA-IASBMPIC MainzIUP BremenJAMSTEC
WSUKNMINIWAUniv. Leicester
PSITNORIVMKNMI
The participants: MAX-DOAS
JAMSTEC → aerosol extinction profiles → VIS → 1km grid;
parameterized
IUP HDB → aerosol extinction profiles → VIS → 200m grid
BIRA → aerosol extinction profiles → UV and VIS → 200m grid
MPI → aerosol extinction profiles → UV → AOD + surface ext. + layer
height + f=0.9 IUP Bremen → AOD → VIS → ?; parameterized
CIMEL sunphotometer (TNO)
→ AOD at different wavelengths & ssalb, phase-function
Nephelometer (PSI,TNO) → surface extinction & ssalb, phase-function
Ramen LIDAR (RIVM) → aerosol extinction profiles
Ceilometer (KNMI) → boundary layer height
Backscatter lidar (RIVM) → boundary layer height
The participants:
…
Results; BIRA
AOD time series
AOD time series
AOD MAXDOAS vs. CIMEL
AOD MAXDOAS vs. CIMEL
Measured O4 DSCD are reduced by ~20% for BIRA, MPI, IUP HDBNot for JAMSTEC and IUP Bremen
With correction Without correction
AOD MAXDOAS vs. CIMEL
Correcting the O4 DSCD
Case: 30° elevation , pointing north, clear-sky , AOD<0.15
Correcting the O4 DSCDBased on the Beijing dataset
→ Measured and simulated O4 DSCD should be equal
But sim. O4 DSCDs = meas. O4 DSCDs * 0.80.1
12
Measured DS SCDO4 is within 2% of the simulated using Hermans et al. cross section at room T (477 nm).
1.02
1.01
1.00
0.99
0.98
Rat
io [s
im S
CD
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181614121086UTC
23-JUNE-2009
3.0
2.5
2.0
1.5
1.0
0.5
0.0
DS
O2-
O2
dSC
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1043
3.53.02.52.01.5Direct sun AMF
DIRECT SUN O2-O2: Coefficient values ± sigma SCDref = -1.53e+43 ± 8.55e+40 VCDmeas = 1.32e+43 ± 4.58e+40 VCDsim = 1.31e+43 Teff = 266 K
23-JUNE-2009
Direct sun results VIS; Elena Spinei
Correcting the O4 DSCD? Are we really sure that the simulations are correct .That the differences are not caused by errors in other forward model parameters
Aerosol optical properties, … Error in measured O4 DSCD
Error in the spectra Error in DOAS fit
? O4 cross-section
No Yes
or
?
?
Influence of ssalb and g
BIRA VIS Heidelberg VIS
JAMSTEC VIS
Contour plots
BIRA UV MPI UV
Contour plots
BIRA VIS
Heidelberg VIS
JAMSTEC VIS
Contour plots; identical scales
BIRA UV
MPI UV
But; better results for f=1.1Uplifted aerosol layer
Contour plots; identical scales
BIRA VIS
Heidelberg VIS
JAMSTEC VIS
Contour plots
BIRA UV MPI UV
Contour plots
BIRA VIS
Heidelberg VIS
JAMSTEC VIS
Contour plots; identical scales
BIRA UV
MPI UV
Contour plots; identical scales
Aerosol inter-comparisons: plans for the future
Retrieving synthetic profiles:
BIRA will provide O4 DSCDs and relative intensities at 4 wavelengths for 4 aerosol cases: low AOD and high AOD; surface layer and up-lifted layer
Try to retrieve the profiles using your best settings; the settings agreed on for the real data.
MAXDOAS
→ Focus on both AOD and profiles
+ Sensitivity tests concerning ssalb, phase function,…
Aerosol inter-comparisons: plans for the future
Real data On your own data set On the Heidelberg dataset (data until October the 5th) Retrievals using your own best settings Retrievals using settings as similar as possible
Apriori extinction: exponential profile, SH=1km, AOD=0.1; Height grid for the simulations: 200m grid to 4km. Covariance matrix: 100% of apriori; 100m or 500m (HDB suggestion). Atmosphere (P,T): USstandard O3+NO2: USstandard Lambertian surface albedo: 5% Aerosol: optical properties are based on mean Nephelometer: g=0.65 and single scattering albedo = 0.95; wavelengths: 360, 477, 577, 630nm if possible
MAXDOAS vs other instruments
Insitu data, nephelometer (Paul Zieger)
Aerosol extinction from Raman LIDAR (Arnoud Apituley)
Paper on MAXDOAS intercomparison and the Nephelometer paper by June-July
→ deadline for data submission: end March
Aerosol inter-comparisons: plans for the future
Summary The agreement between the different aerosol retrievals has already improved compared to the previous workshop
Questions
What’s up with the O4 DSCD?What can we actually achieve?(what is our sensitivity, how sensitive are we towards forward model parameters and towards a-priori information, can we obtain “substitute aerosol profiles” for clouds,…)
Conclusion for now
We are making progress
But we still have a lot of work to do; a lot of questions to answer
