First results of the aerosol profiling group IUP Heidelberg BIRA-IASB MPIC Mainz IUP Bremen...

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

/ m

easu

red

SCD

]

181614121086UTC

23-JUNE-2009

3.0

2.5

2.0

1.5

1.0

0.5

0.0

DS

O2-

O2

dSC

D x

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