DOAS-Gruppe: Institut für Umweltphysik Universität Bremen [email protected] Promotionsvortrag, 28. April 2006,

DOAS-Gruppe:DOAS-Gruppe:http://www.doas-bremen.dehttp://www.doas-bremen.de

Institut für UmweltphysikInstitut für UmweltphysikUniversität BremenUniversität Bremen

[email protected]@iup.physik.uni-bremen.de

Promotionsvortrag, 28. April 2006Promotionsvortrag, 28. April 2006, Bremen, Bremen

Folkard WittrockInstitut für

UmweltphysikUniversität Bremen

NORS/NDACC UV/Vis MeetingJuly 3 to 4, 2012, Brussels, Belgium

Status paper

xKy

• Internal review process until July 15

• Send around to all authors, collect comments by August 10

• Submit August 20








MAX-DOAS profile retrieval (I)

• Optimal Estimation using a priori information• Online calculation of block-AMFs and describe relation

between measurements (SCDs of trace gas for different elevations) and absorber profile as a linear inversion problem:

• Solve by Optimal estimation method (therefore adding a trace gas a priori profile)

• BIRA, NIWA, WSU, Heidelberg, Leicester/Leeds and Bremen

knesslayer thic ,T ,p AMF,-blockon depends :K

jlayer in ion concentrat :x

i)direction (:

jjij

j

i SCDyxKy








• Inversion by parametrisation of trace gas profiles

• 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)

• Lookup tables for AMF, least squares fit

• MPI Mainz, similar approach used by JAMSTEC, KNMI

MAX-DOAS profile retrieval (II)

Data included – three-fold comparisonSimulation(provided by BIRA)

Real Data- focus on Bremen data(fixed aerosol)

Real Data(aerosol retrieval included

UV VIS UV VIS UV VIS

BIRA

IUP-B

IUP-H

JAMSTEC

MPI

NIWA

WSU

KNMI

Leeds

To identify each methods possibilitiesWhat are pros and cons?

To identify each methods possibilitiesWhat are pros and cons?

How consistent are the results in the real world?

How consistent are the results in the real world?

How do they compare to other instruments?

How do they compare to other instruments?








• IASB-BIRA has provided modeled NO2 slant columns for UV and visible, using

– different NO2 scenarios (profiles)

– Two aerosol loadings (AOD 0.14 and 0.54 for 477 nm)– Simulations for June 24, 2009 in Cabauw– 10 Elevation Angles (1,2,4,5,6,8,10,15,30,89)– SCD error based on real DOAS fit errors plus Gaussian noise– Calculations with RTM LIDORT

Simulation study








Simulation study








For all comparisons . ..

• We are focusing on two parameters:

• Tropospheric column <-> important for satellite validation)

• VMR close to the surface <-> easy to compare with in situ data

• MAX-DOAS as a link between satellite and in situ (air pollution) network.








8

2

4

6

NO

2 C

olum

n [1

015

mol

ec/c

m2 ]

tropospheric column, low NO2, exponential profile, UV








9

10

20

30

N

O2

Col

umn

[10

15 m

olec

/cm

2 ]

tropospheric column, high NO2, exponential profile, UV








10

4

6

NO

2 C

olum

n [1

015

mol

ec/c

m2 ]

tropospheric column, low NO2, block profile, UV








11

20

30

N

O2

Col

umn

[10

15 m

olec

/cm

2 ]

tropospheric column, high NO2, block profile, UV








12

1

2

3

4

5

6

NO

2 C

olum

n [1

015

mol

ec/c

m2 ]

tropospheric column, low NO2, very shallow layer, UV








13

3

6

9

12

15

18

N

O2

Col

umn

[10

15 m

olec

/cm

2 ]tropospheric column, low NO

2, less shallow layer, UV








14

1

2

3

4

5

NO

2 C

olum

n [1

015

mol

ec/c

m2 ]

tropospheric column, low NO2, upper layer, UV








15

5

10

15

20

25

30

35

N

O2

Col

umn

[10

15 m

olec

/cm

2 ]

tropospheric column, high NO2, upper layer, UV








16

2

4

NO

2 V

MR

in lo

wes

t 200

m [p

pbV]

VMR in lowest 200m, low NO2, exponential profile, UV








17

3

6

9

12

15

N

O2

VM

R in

low

est 2

00m

[ppb

V]

VMR in lowest 200m, high NO2, exponential profile, UV








18

1

2

3

4

NO

2 V

MR

in lo

wes

t 200

m [p

pbV]

VMR in lowest 200m, low NO2, block profile, UV








19

6

9

12

N

O2

VM

R in

low

est 2

00m

[ppb

V]

VMR in lowest 200m, high NO2, block profile, UV








20

3

6

9

12

N

O2

VM

R in

low

est 2

00m

[ppb

V] VMR in lowest 200m, high NO

2, very shallow layer, UV








21

5

10

15

20

25

N

O2

VM

R in

low

est 2

00m

[ppb

V]

VMR in lowest 200m, high NO2, less shallow layer, UV








22

1

2

3

NO

2 V

MR

in lo

wes

t 200

m [p

pbV]

VMR in lowest 200m, low NO2, upper layer, UV








23

1

2

3

4

5

NO

2 V

MR

in lo

wes

t 200

m [p

pbV]

VMR in lowest 200m, high NO2, upper layer, UV








24








25








26








27








28








Conclusions from simulation study

• VC and surface layer values usually captured well, difference to true value for most scenarios less than 25%

• Viewing directions towards sun (RAA < 20°) and for high SZA (>75°) for some algorithms difficult to retrieve

• LOS < 3° crucial for proper profile retrieval• 1.5 < DoF < 3• Results in the visible have less scatter, in particular for high aerosol

load (not surprising)








Conclusions from simulation study

•„Best“ settings for OE:• Finer grid gives more details (shallow and very shallow layer) and

for some algorithms better agreement (Bremen, NIWA, WSU) to reference data

• From Bremen experience the retrieval profits from using both wavelength regions in parallel

Documents

DOAS-Gruppe: Institut für Umweltphysik Universität Bremen [email protected] Promotionsvortrag, 28. April 2006,