1. the mpi max-doas inversion scheme 2. cloud classification 3. results: aerosol od: correlation...

1. The MPI MAX-DOAS inversion scheme2. Cloud classification3. Results: • Aerosol

• OD: Correlation with AERONET• Surface extinction: Correlation with Nephelometer• Mixing Layer Height: Correlation with Ceilometer

• NO2 • Surface mixing ratio: Correlation with EMPA • Mixing Layer Height: Correlation with Ceilometer• Inversion of synthetic NO2 SCDs

4. Conclusions

Results of the profile inversion from MPI MiniMAX-DOAS measurements during CINDI

Thomas Wagner, Reza Shaigan, Steffen Beirle

MPI Mainz, Germany

Aerosol profiles are parametrised by 3 parameters:following the ideas of

Li, X., Brauers, T., Shao, M., Garland, R. M., Wagner, T., Deutschmann, T., and Wahner, A.: MAX-DOAS measurements in southern China: retrieval of aerosol extinctions and validation using ground-based in-situ data, Atmos. Chem. Phys., 10, 2079-2089, 2010.

A) vertical optical depth OD(related to total aerosol amount)

B) mixing layer height MLH (important atmospheric parameter)

C) fraction of total optical depth in boundary layer (allows to adjust vertical profile, depending e.g. on vertical mixing into free troposphere) f = 0.9

90%Constant extinction in ML, exponential decrease above

1. The MPI MAX-DOAS inversion scheme

f = 1.5

New (since Nov. 2009):

f > 1:

Profiles with elevated layers




f = 1.1

New (since Nov. 2009):

f > 1:

Profiles with elevated layers




Multi-layer aerosols can not

be described by this parametrisation

Modelling of O4 AMFs:

•Radiative transfer modelling:• Backward Monte-Carlo RTM McArTim (Deutschmann, 2009)

• Surface albedo: 5%

• Surface altitude of measurement site

• Pressure and temperature profiles from US standard atmosphere

• Greenblatt et al. O4 cross section (corrected by +15% to +25%)

• Single scattering albedo: 0.95

• Asymmetry parameter: 0.68

• Number of aerosol scenarios: 172480

MLH (14): 20, 100, 200, 300, 500, 700, 1000, 1200, 1500, 1750, 2000, 2500, 3000, 5000m

OD (10): 0.05, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0, 1.5, 2.0, 3.0

f (11): 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 1.0, 1.1, 1.2, 1.5, 1.8

for 8 elevation angles and 14 SZA / rel. Azimuth angles


Parametrisation of NO2 profiles in a similar way:

A) mixing layer height MLH (important atmospheric parameter)

B) fraction f of total VCD in boundary layer (allows to adjust vertical profile, depending e.g. on vertical mixing into free troposphere)

However, no absolute tropospheric VCD is varied, because NO2 AMF depends only on relative profile


Aerosol inversion:

Modelled AMFs are fitted to the measured data in the following way:

Measurements:

-Subtraction of O4 DSCD at 90° for each elevation sequence

-Division by O4 VCD => O4 DAMF

Model results:

-Subtraction of O4 AMF at 90° for each elevation sequence => O4 DAMF

Least squares fit: OD, ML (f: fixed)


Result of aerosol fit, Cabauw, 26.6. Sequence 6

Min: 0.0054 for layer height 0.5km, optical depth: 0.23


NO2 inversion:

Modelled AMFs are fitted to the measured data in the following way:

Measurements:

- Subtraction of NO2 DSCD at 90° for each elevation sequence

- Division by (shifted) DSCD at 10°

Model results (calculated for specific aerosol scenario):

- Subtraction of NO2 AMF at 90° for each elevation sequence => NO2 DAMF

- Division by DAMFs at 10°

Least squares fit: ML (f: fixed)

Aerosol parameter from O4 inversion


Result of NO2 fit, Cabauw

30.6. sequence 5930.6. sequence 62

Chi2 = 0.05Chi2 = 0.004


Classification of the cloud cover

using radiance and O4 observations at 90° elevation angle

Temporal variation of radiance smooth?yes => Temporal variation of O4 smooth?

yes => clear dayno => cloudy day

no => cloudy day

O4 absorption largely increased and/or varying rapidly compared to clear day?

yes => thick cloud

no => thin cloud

2. Cloud classification

Day with clear sky

24.6.2009

6/24/09 04:48 6/24/09 09:36 6/24/09 14:24 6/24/09 19:12

Tim e

1E+5

1E+6

1E+7

Rad

ianc

e [c

ount

s/se

c]

0.0

0.2

0.4

0.6

CI

(rat

io 3

20/4

40)

0.0E+0

1.0E+3

2.0E+3

3.0E+3

O

4 D

SC

D

[1e4

0]

Cabauw

Bruxelles


6/26/09 04:48 6/26/09 09:36 6/26/09 14:24 6/26/09 19:12

Tim e

1E+5

1E+6

1E+7

Rad

ianc

e [c

ount

s/se

c]

0.0

0.2

0.4

0.6

C

I (r

atio

320

/440

)

0.0E+0

1.0E+3

2.0E+3

3.0E+3

O

4 D

SC

D

[1e4

0]

Day with 'thin' clouds

26.06.2009

Cabauw

Bruxelles


Day with 'thick' clouds

1.7.2009

7/12/09 04:48 7/12/09 09:36 7/12/09 14:24 7/12/09 19:12

Tim e

1E+5

1E+6

1E+7

Rad

ianc

e [c

ount

s/se

c]

0.0

0.2

0.4

0.6

CI

(rat

io 3

20/4

40)

0.0E+0

1.0E+3

2.0E+3

3.0E+3

O

4 D

SC

D

[1e4

0]

Cabauw

Bruxelles


Classification of the cloud cover using radiance and O4 observations at 90° elevation angle

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

4

22.6 26.6 30.6 4.7 8.7 12.7

Time

Diff

eren

ce o

f O4

AM

F

Clear skyThick cloudsThin clouds

O4 AMF – O4 AMFcloudfree


A) Typical diurnal cycles

B) Aerosol OD: Correlation with AERONET data

C) Surface extinction: Correlation with WetNephelometer data

D) Mixing Layer Height: Correlation with Ceilometer data

3.1 Results: Aerosols

0

0.2

0.4

0.6

0.8

1

1.2

1.4

24.Jun00:00

24.Jun02:24

24.Jun04:48

24.Jun07:12

24.Jun09:36

24.Jun12:00

24.Jun14:24

24.Jun16:48

24.Jun19:12

24.Jun21:36

25.Jun00:00

Time

Aer

osol

OD

360

nm

OD_f0.5

OD_f0.9

OD_f1.1

OD_f1.5

AOT_360

f: 0.5f: 0.9f: 1.1f:1.5AERONET

Clear sky

cloudy

3.1 Results: Aerosols A) Typical diurnal cycles

0

0.2

0.4

0.6

0.8

1

1.2

1.4

03.Jul02:24

03.Jul04:48

03.Jul07:12

03.Jul09:36

03.Jul12:00

03.Jul14:24

03.Jul16:48

03.Jul19:12

03.Jul21:36

Time

Aer

osol

OD

360

nm

OD_f0.5

OD_f0.9

OD_f1.1

OD_f1.5

AOT_360

f: 0.5f: 0.9f: 1.1f:1.5AERONET

mostly cloudy

Clear sky

3.1 Results: Aerosols A) Typical diurnal cycles

y = 0.8383x + 0.1987

R2 = 0.1992

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2 1.4

AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

All coincidences (half hour averages)

3.1 Results: Aerosols B) Correlation with AERONET OD

O4 scaling factor = 1.2f=0.9

y = 0.7003x + 0.1374

R2 = 0.2092

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2 1.4

AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

Data with layer heigth >= 3km removed


y = 0.6805x + 0.1331

R2 = 0.2517

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2 1.4

AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

Also data with chi2 >= 0.04 removed


0

0.5

1

1.5

2

2.5

3

3.5

29.0602:24

29.0607:12

29.0612:00

29.0616:48

29.0621:36

30.0602:24

30.0607:12

30.0612:00

30.0616:48

30.0621:36

Time

MA

X-D

OA

S O

D 3

60nm

Days with (unrealistic) rapid variation of the aerosol OD:


y = 0.7022x + 0.0401

R2 = 0.6364

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2 1.4

AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

Data with rapid variation of OD (> 0.5) removed


y = 0.7467x + 0.0337

R2 = 0.5037

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2 1.4

AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

Only data for thin clouds


y = 0.5497x + 0.0578

R2 = 0.9011

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2 1.4

AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

Only data for clear sky

Coincidences only in the morning!(with systematically low MAX-DOAS results)


y = 0.521x + 0.5985

R2 = 0.0657

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2 1.4

AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

Only data for thick clouds


Correlation with WetNephelometer data from Paul Zieger

3.1 Results: Aerosols C) Correlation with in-situ extinction

Correlation with WetNephelometer data from Paul Zieger for different layer heights

>1500m:Slope 2

<1500m Slope 1

0

500

1000

1500

2000

2500

0:00 4:48 9:36 14:24 19:12 0:00Time

Laye

r he

ight

[m]

MAX-DOAS aerosol layer height

F-value: 0.9

F-value: 1.1

3.1 Results: Aerosols D) Correlation with Ceilometer MLH

y = 0.2371x + 2210.9

R2 = 0.0077

y = -0.0422x + 1457.5

R2 = 0.00030

1000

2000

3000

4000

5000

6000

0 200 400 600 800 1000 1200 1400 1600 1800 2000Ceilmeter_MLH1 [m]

MA

X-D

OA

S L

ayer

hei

ght [

m]

MAX-DOAS_F09MAX-DOAS_F11Linear (MAX-DOAS_F09)Linear (MAX-DOAS_F11)

all data


only clear sky observations and chi2 < 0.04

y = 1.242x + 686.27

R2 = 0.2589

y = 1.7872x + 1126.9

R2 = 0.1675

0

1000

2000

3000

4000

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Ceilometer MLH1 [m]

MA

X-D

OA

S a

eros

ol la

yer

heig

ht [m

]

MAX-DOAS_F09MAX-DOAS_F11Linear (MAX-DOAS_F11)Linear (MAX-DOAS_F09)


3.2 Results: NO2

A) Typical diurnal cycles

B) Mixing ratio: Correlation with EMPA data

C) Mixing Layer Height: Correlation with Ceilometer data

D) Inversion of synthetic NO2 DSCDs

0

2

4

6

8

10

12

14

16

18

20

25.Jun02:24

25.Jun04:48

25.Jun07:12

25.Jun09:36

25.Jun12:00

25.Jun14:24

25.Jun16:48

25.Jun19:12

25.Jun21:36

Time

NO

2 M

ixin

g ra

tio [

ppb]

EMPA in-situ

NO2 mixing ratio for different aerosol f-values

thin clouds

3.2 Results: NO2 A) Typical diurnal cycles

0

2

4

6

8

10

12

14

16

18

20

25.Jun02:24

25.Jun04:48

25.Jun07:12

25.Jun09:36

25.Jun12:00

25.Jun14:24

25.Jun16:48

25.Jun19:12

25.Jun21:36

Time

NO

2 M

ixin

g ra

tio [p

pb]

NO2_mix_NO2_0.2NO2_mix_NO2_0.5NO2_mix_NO2_0.8NO2_mix_NO2_0.9NO2_mix_NO2_1.0NO2 in-situ

thin clouds

NO2 mixing ratio for different NO2 f-values

3.2 Results: NO2 A) Typical diurnal cycles

y = 0.7159x + 2.1508

R2 = 0.2153

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 20

NO2 mixing ratio EMPA [ppb]

MA

X-D

OA

SN

O2

mix

ing

ratio

[ppb

]

All coincidences (half hour averages, f-value: 0.9)

3.2 Results: NO2 B) Correlation with EMPA mixing ratio

y = 0.7449x + 1.2219

R2 = 0.3507

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 20


MA

X-D

OA

S m

ixin

g ra

tio [p

pb]

All coincidences (half hour averages, f-value: 0.9)

Chi2 < 0.04


y = 0.9381x + 0.2634

R2 = 0.7211

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 20


MA

X-D

OA

S m

ixin

g ra

tio N

O2

[ppb

]

Only thin clouds


y = 0.4506x + 0.949

R2 = 0.5023

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 20


MA

X-D

OA

S N

O2

mix

ing

ratio

[ppb

]

clear sky

(only early morning data)


y = 2.3134x - 2.8438

R2 = 0.556

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 20


MA

X-D

OA

S N

O2

mix

ing

ratio

[ppb

]

Only thick clouds



Slope of fit R2

All data 0.72 0.22

chi2<0.04 0.74 0.35

thin clouds 0.94 0.72

clear sky 0.45 0.50

thick clouds 2.31 0.56

On some days the NO2 mixing ratios depend strongly on the assumed (relative) aerosol profile.

The mixing ratios derived for an elevated aerosol layer (f>1) agree better with the in-situ data.

For these observations also the lowest chi2 is found in the aerosol fit (O4 data) for an assumed elevated aerosol layer


0

2

4

6

8

10

12

14

16

18

20

26.Jun02:24

26.Jun04:48

26.Jun07:12

26.Jun09:36

26.Jun12:00

26.Jun14:24

26.Jun16:48

26.Jun19:12

26.Jun21:36

Time

NO

2 M

ixin

g r

atio [

ppb]

NO2_mix_Aerosol_0.9NO2_mix_Aerosol_1.0NO2_mix_Aerosol_1.1NO2 in-situ

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

26.Jun02:24

26.Jun04:48

26.Jun07:12

26.Jun09:36

26.Jun12:00

26.Jun14:24

26.Jun16:48

26.Jun19:12

26.Jun21:36

Time

Chi^

2Chi2_0.9Chi2_1.0Chi2_1.1

Lowest chi2 for elevated aerosol layer

Better agreement of NO2 mixing ratio for elevated aerosol layer


3.2 Results: NO2 C) Correlation with Ceilometer MLH

Slope of fit R2

All data 0.48 0.79 0.13 0.23

chi2<0.04 0.52 0.90 0.32 0.39

thin clouds 0.56 0.91 0.34 0.37

clear sky 0.80 1.15 0.52 0.55

thick clouds 0.32 0.35 0.11 0.07

Aerosol fit: f=0.9 f=1.1

Fit results for all daily profiles (UV profile 03)

F-value

Layer height

NO2 VCD

Chi2

3.2 Results: NO2 D) Inversion of synthetic NO2 DSCDs

(UV profile 03, all daily profiles)


Results for all UV profiles


-simple MAX-DOAS inversion scheme for UV measurements, based on MC-RTM LUT and least squares fit of simple profile parametrisation

-discrimination scheme for clear sky / thin clouds / thick clouds

Aerosol inversion:

-aerosol OD is reasonable for aerosol f-value of 0.9, clear sky and thin cloud observations; MAX-DOAS aerosol OD about 25% smaller than AERONET

-aerosol extinction agrees well with wetnepelometer data for layer heights <1500m

-aerosol layer height shows (weak) correlation with ceilometer data only for clear sky

4. Conclusions

NO2 inversion:

-NO2 mixing ratio agrees well with in-situ observations for clear sky and thin cloud observations; only weak dependence on aerosol f-value; almost no dependence on NO2 f-value

-NO2 layer height shows reasonable correlation with ceilometer data for clear sky and thin cloud data

Inversion of synthetic NO2 SCDs

-good agreement found for NO2 profiles for low and high aerosol load

-for some profiles rather large deviations during the day

4. Conclusions

y = 0.6884x + 0.021R2 = 0.5416

y = 0.7467x + 0.0337R2 = 0.5037

y = 0.6606x + 0.1803R2 = 0.3198

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 0.2 0.4 0.6 0.8 1 1.2 1.4AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

Factor_10_f09

Factor_095_f09

Factor_09_f09

Linear(Factor_10_f09)Linear(Factor_095_f09)Linear(Factor_09_f09)

different scaling factors for the O4 cross section

(observations for thin clouds)

+20 % seems to be the best choice


+15 %

+20 %

+25 %

y = 0.7467x + 0.0337

R2 = 0.5037

y = 1.0305x + 0.1673

R2 = 0.3008

y = 0.2296x + 0.0949

R2 = 0.50550

0.5

1

1.5

2

2.5

0 0.2 0.4 0.6 0.8 1 1.2 1.4

AERONET OD 360nm

MA

X-D

OA

S O

D 3

60nm

Factor_095_f02Factor_095_f05Factor_095_f08Factor_095_f09Factor_095_f10Factor_095_f11Factor_095_f12Factor_095_f15Factor_095_f18Linear (Factor_095_f09)Linear (Factor_095_f02)Linear (Factor_095_f18)

Correlations for different f-.values

(observations for thin clouds)

0.9 seems to be a good choice


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

25.Jun03:36

25.Jun06:00

25.Jun08:24

25.Jun10:48

25.Jun13:12

25.Jun15:36

25.Jun18:00

Time

Ae

roso

l Ext

inct

ion

[1

/km

]

ext_f0.2ext_f0.5ext_f0.8ext_f0.9ext_f1.0ext_f1.1ext_f1.2ext_f1.5

Aerosol extinction for different aerosol f-values

thin clouds

3.1 Results: Aerosols

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

03.Jul03:36

03.Jul06:00

03.Jul08:24

03.Jul10:48

03.Jul13:12

03.Jul15:36

03.Jul18:00

03.Jul20:24

Time

Ae

roso

l Ext

inct

ion

[1

/km

]

ext_f0.2ext_f0.5ext_f0.8ext_f0.9ext_f1.0ext_f1.1ext_f1.2ext_f1.5

clear skycloudy sky

3.1 Results: AerosolsAerosol extinction for different aerosol f-values

0

5

10

15

20

25

30

35

40

0 5 10 15 20


MA

X-D

OA

S N

O2

mix

ing

ratio

[ppb

]

NO2f09_aer02NO2f09_aer05NO2f09_aer08NO2f09_aer09NO2f09_aer10NO2f09_aer11NO2f09_aer12NO2f09_aer15NO2f09_aer18Linear (NO2f09_aer02)Linear (NO2f09_aer08)Linear (NO2f09_aer10)Linear (NO2f09_aer12)Linear (NO2f09_aer18)

y = 1.0632x + 0.2259, R2 = 0.678

y = 0.9407x + 0.3009, R2 = 0.7168

y = 0.9338x + 0.2464, R2 = 0.721

y = 0.6263x + 0.8643, R2 = 0.6754

y = 0.6142x + 0.9857, R2 = 0.6386

for different aerosol f-values (thin cloud data)


0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 20


MA

X-D

OA

S N

O2

mix

ing

ratio

[pp

b]

NO2f02_aer05NO2f05_aer05NO2f08_aer05NO2f09_aer05NO2f10_aer05

y = 0.9717x + 0.3211, R2 = 0.7096y = 1.0283x + 0.135, R2 = 0.7167y = 0.9981x + 0.207, R2 = 0.6989y = 0.9981x + 0.207, R2 = 0.6989y = 0.9816x + 0.2562, R2 = 0.6929

for different NO2 f-values (thin cloud data)

Almost no dependence on NO2 f-value


0

2

4

6

8

10

12

14

16

18

20

26.Jun02:24

26.Jun04:48

26.Jun07:12

26.Jun09:36

26.Jun12:00

26.Jun14:24

26.Jun16:48

26.Jun19:12

26.Jun21:36

Time

NO

2 M

ixin

g r

atio [

ppb]

NO2_mix_Aerosol_0.9NO2_mix_Aerosol_1.0NO2_mix_Aerosol_1.1NO2 in-situ

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

26.Jun02:24

26.Jun04:48

26.Jun07:12

26.Jun09:36

26.Jun12:00

26.Jun14:24

26.Jun16:48

26.Jun19:12

26.Jun21:36

Time

Chi^

2Chi2_0.9Chi2_1.0Chi2_1.1

Day with better agreement for elevated layer

(some periods)

Lowest chi2 for elevated aerosol layer

Better agreement of NO2 mixing ratio for elevated aerosol layer


y = 0.7945x + 400.99

R2 = 0.2293

y = 0.4812x + 390.21

R2 = 0.133

0

500

1000

1500

2000

2500

3000

0 500 1000 1500 2000Ceilometer MLH1 [m]

MA

X-D

OA

S N

O2

laye

r he

ight

[m]

Reihe1Reihe2Linear (Reihe2)Linear (Reihe1)

aerosol f-value: 0.9aerosol f-value: 1.1

(all data, NO2 f-value: 0.9)


y = 0.8992x + 343.95

R2 = 0.393

y = 0.5188x + 354.32

R2 = 0.31910

500

1000

1500

2000

2500

3000

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Ceilometer MLH1 [m]

MA

X-D

OA

S N

O2

laqy

er h

eigh

t [m

]



NO2 Chi2 <0.04


y = 0.9146x + 321.42

R2 = 0.3747

y = 0.555x + 300.26

R2 = 0.34080

500

1000

1500

2000

2500

3000

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Ceilometer MLH1 [m]

MA

X-D

OA

S N

O2

laqy

er h

eigh

t [m

]



Only thin clouds


y = 1.1512x + 224.52

R2 = 0.5465

y = 0.8048x + 304.4

R2 = 0.51640

500

1000

1500

2000

2500

3000

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Ceilometer MLH1 [m]

MA

X-D

OA

S N

O2

laqy

er h

eigh

t [m

]



Only clear sky


y = 0.3484x + 761.79

R2 = 0.0728

y = 0.3162x + 467.65

R2 = 0.10550

500

1000

1500

2000

2500

3000

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Ceilometer MLH1 [m]

MA

X-D

OA

S N

O2

laqy

er h

eigh

t [m

]



Only thick clouds


1. the mpi max-doas inversion scheme 2. cloud classification 3. results: aerosol od: correlation...

Documents

mpi maxdoas inversion

mpi maxdoas inversion

profile inversion

vertical mixing

mpi minimaxdoas measurements

empa mixing layer height

boundary layer

aerosol od