current status and future perspectives of...

Mainz 1.7.2004 [email protected] http//:satellite.iup.uni-heidelberg.de

Current status and future perspectives of atmospherictrace gas observations from space

Thomas Wagner

Institut für Umweltphysik, University of Heidelberg


⇒ Outline

• Method: DOAS for satellite instruments

• UV/vis/NIR satellite instruments

• What can we expect – what not?

• Results from the last 8 years (GOME, SCIA)

• Future Satellite instruments (until 2020)


When it all started....⇒ History

Joseph von Fraunhofer (1787-1826)

„I found very many strong and weak vertical lines, which are darker than the remaining part of the spectrum. Some of them are almost dark“

Solar spectrum, painted byJoseph von Fraunhofer (1814)

Further Milestones:

• first big achromatic objectives for long-glasses

• first use of refractive gratings, first absolute Wavelength determination

• Determination of the position of 234 of the > 500 lines he had doscovered


⇒ Method DOAS: ’Differential Optical Absorption Spectroscopy’

A) Lambert-Beer Law: ( )I I c l= ⋅ − ⋅ ⋅0 exp σ

B) Spectra, High pass filtering

480 500 520Wavelength [nm]

0

1

2

3

σ [10 -21 cm

-2 ]

-0.2

0.0

0.2

σ ' [10

-21 cm

-2 ]

σ

σc

σ'• High Sensitivity (OD≤0.001)• Io not known• Several absorbers• Separation between scattering

and absorption


1960 1970 1980 1990 2000

Sputnik

Satellites

Weather Satellites

Ozone(BUV)

Ozone(TOMS)

Ozone++(spectra)

UV/vis satellite history

Explorer

TIROS NIMBUS-4

NIMBUS-7

NOAA-9

NOAA-11 NOAA-14

Space shuttle

METEOR-3 Earth-probe

ADEOS

GOME SCIAMACHY

NIMBUS-7

⇒ Instruments


⇒ Instrument GOME/SCIAMACHY-Spectral regions

Spectral resolution:

0.2 – 1.5 nm


⇒ Data analysis

Spectral Analysis (DOAS)

spectrum

Trace gas cross sections

SCD

Radiative transfer modelling ‚AMF‘

Profile informtion

VCDStrat.-Trop. Separation Reference sector method

VCDtropindep-. Meas., ModelsProfile information

concentration


1E+08

1E+10

1E+12

1E+14

1E+16

200 300 400 500 600 700 80Wavelength [nm]

Inte

nsity

[arb

itrar

y un

its

O3 UV

O3 vis

HCHO

OClO

O4

O2

H2O

SO2 NO2 BrO

Satellite group: http://giger.iup.uni-heidelberg.de/

Set of Atmospheric Abosrbers Identified in GOME Spectra at the Satellite Group at the Institut für Umweltphysik

Atmospheric trace gas absorptions detected in Satellite spectra

⇒ Data analysis


⇒ Data analysisAMF: measure of sensitivity

20 30 40 50 60 70 80 90SZA [°]

0

4

8

12

AMF

albedo 0.8

albedo 0.0

stratospheric AMF

tropospheric AMF

geometric AMF

AMF for Stratosphere and Troposphere from radiative transport modelling


Global Mean tropospheric NO2 VCD⇒ Results

Steffen Beirle, IUP Heidelberg


⇒ Results

What can we not expect from UV/vis satellite observations?

- high spatial resolution (>15 x 30km²)

- high sampling rate for a given location (SCIA: every 6 days)

- high sensitivity for species close to the ground

- good vertical resolution in the troposphere

- high accuracy for tropospheric species

What can we expect from UV/vis satellite observations?

- (Nearly) global coverage [excluding (polar) night]

=> spatial and temporal variability

- Stability of instruments

- Observations in remore regions


⇒ Results

What can you expect from the rest of the talk?

……Examples of:

- Discoveries

- Identification, characterization and quantification of sources

- Estimation of atmospheric lifetimes

- Identification of long range transport, comparison to models

- Trends


⇒ Discoveries

Bromine explosion:

GOME tropospheric BrO during polar spring in both hemispheres

=> Natural phenomenon

September, 20-28, 1997


⇒ Discoveries

Dependence of tropospheric BrO on latitude and time

1 2 3 4 [1013 molec/cm²]

40

45

50

55

60

65

70

75

80

85La

titud

e [d

egre

e]

SZA > 87

Dec January February March April May June

Arctic

=> Relationship between bromine explosion and one year old sea ice

1 2 3 4 [1013 molec/cm²]

40

45

50

55

60

65

70

75

80

85

Latitud

e [deg

ree]

SZA > 87

Average Extension of Sea Ice

Jun July August September October November Dec

Antarctic


Comparison with observations from other platforms => Potential tropospheric BrO background

⇒ Discoveries

0E+0

2E+13

4E+13

6E+13

8E+13

VCD

BrO

[mol

ec/c

m]

balloon

ground

GOME

Kiru

na,

14.0

2.19

97

Kiru

na,

10.0

2.19

99

Leon

,23

.11.

1996

SAOZ

DOAScl

ear s

ky

clea

r sky

BrO profile?

Balloon data: I. Pundt, H. Harder


Activation on Mountain Lee Waves⇒ Discoveries

Sven Kühl, IUP Heidelberg

Almost complete activation over an altitude range of about 10 km

20.01.1997 21.01.1997 22.01.1997

On the 21st of January, a sudden increase of the OClO SCDs is seen over northern Scandinavia, the same region where strong activity of mountain waves has been reported for the same day (Dörnbrack et al., 1999).


⇒ Discoveries

Mesoscale temperatures from MM5 analysis

(Andreas Dörnbrack)

Blue indicates strong cooling

475 K


⇒ Results


Examples of:

- Discoveries




- Trends


⇒ Sources CO VCD from SCIA, February 2004Christian Frankenberg, IUP Heidelberg


CH4 VCD (scaled by CO2 VCD) from SCIA, Christian Frankenberg, IUP Heidelberg

⇒ Sources

May 2004


Global Maps reflect distribution of sources⇒ Sources

Jun –Sep 1997HCHO SCD (T. Marbach, IUP Heidelberg) SO2 SCD (M.F. Khokhar, IUP Heidelberg)

Dec 1996

BrO VCD (J. Hollwedel, IUP Heidelberg) H2O VCD (T. Wagner, IUP Heidelberg)

Jan – Feb1996 &1999

1996 - 2001


⇒ Sources Comparison of different trace gases

SO2 NO2

Industry

(Highveld,S-Africa)

Volcaneos

(M.F. Khokhar, S. Beirle, IUP-Heidelberg)


⇒ Sources Comparison of different trace gases

HCHO NO2

=> biogenic emissions => anthropogenic emissions

(T. Marbach, S. Beirle, IUP-Heidelberg)


⇒ Sources Humidity follows the surface temperatures

Average H2O VCD, Jan & Feb Strong El-Nino (1998)

[molec/cm²]


⇒ Sources Humidity follows the surface temperatures

Average H2O VCD, Jan & Feb ‚normal years‘ (1996, 1997, 2000, 2001)

[molec/cm²]


⇒ Sources Comparison of different data sets

GPCP mean precipitationGOME H2O VCD

El-Nino conditions Jan-Feb 1998

‚Normal conditions‘ Jan-Feb 1996 & 1999


1.0E+23

1.5E+23

2.0E+23

Jan. 96 Dez. 96 Jan. 98 Jan. 99 Jan. 00 Jan. 01 Jan. 02 Jan. 03 Jan. 04

1.0E+23

1.5E+23

2.0E+23


El Nino

1.0E+23

1.5E+23

2.0E+23


1.0E+23

1.5E+23

2.0E+23


El-Nino,

Temporal pattern

+

–

El-Nino –Normal years

⇒ Sources

Sea surface temperature anomaly


ATSRATSRFire counts⇒ Sources Fire counts

Strong biomass burning in Indonesia duringSeptember 1997

(El Nino 1997/1998)

GOME HCHO GOME SO2 GOME NO2

S. Beirle,IUP Heidelberg

M. F. Khokhar,IUP Heidelberg

T. Marbach,IUP Heidelberg


⇒ Sources Anthropogenic sources: weekly cycle of NO2

Beirle et al., Weekly cycle of NO2 by GOME measurements, ACP 3, 2225-2232, 2003

US

Eas

tcoa

st

Eur

ope

1015molec/cm2


⇒ SourcesWeekly Cycle of tropospheric NO2

rel.

units

(Steffen Beirle, IUP-Heidelberg)


⇒ Sources NOx from ships

Estimated NOx

emissions (Endresen et al.)

GOME NO2 VCD

(Meridional high-pass filter applied)

1013molec/cm2Beirle et al., Estimate of NOx emissions from shipping, submitted to GRL, 2004


⇒ Lifetime Anthropogenic sources: NOx from ships

Beirle et al., Estimate of NOx emissions from shipping, submitted to GRL, 2004

Lifetime estimation:

3.7 hoursShip emissions (Gg [N]/yr):

26 (11-81)

With fixed lifetime:

26 (17-42)

EDGAR: 34

Endresen: 41-54

Corbett: 22/44

Winter: ITCZ south, Summer: ITCZ north


⇒ Results


Examples of:

- Discoveries




- Trends


⇒ Transport Comparison GOME - Models

Intercontinental transport of anthropogeneous NO2 measured by GOME and modeled by FLEXPART [Stohl et al., 2003]


Difference: NAO+ - NAO-

(1996-2002)⇒ Transport

Model results from FLEXPART GOME tropospospheric NO2

Influence of the North Atlantic Oscillation on the tropospheric transport paths [Eckhardt et al., 2003]


Change of global circulation due to El-Nino⇒ TransportRelative deviation of the GOME H2O VCD from the long year mean

October 1997 – March 1998

humidity


Change of global circulation due to El-Nino⇒ TransportRelative deviation of the cloud shielding (from O2 absorption) from the long year mean

October 1997 – March 1998

clouds


⇒ Results


Examples of:

- Discoveries




- Trends


⇒ Trends

Monthly meanareas with enhanced BrO VCD

Systematic Increase from 1996 to 2001J. Hollwedel, IUP-Heidelberg


DOAS H2O analysis⇒ Trends

610 630 650 670

Wavelength [nm]

-0.03

-0.01

-0.10

-0.05

0.00

-0.10

-0.05

0.00

Opt

ical

den

sity

-0.01

0.00

0.01

GOME, 04.12.1996, 08:30 UT SZA: 33°, Lat: 5°, Long 31°

O4

O2

H2O

residual

29.6

30.0

30.4 Raw Spectrum

-0.06

-0.04Ring

Instrument stability from Fraunhofer lines

H2O Trends

Trends in cloud cover from O2 and O4 absorptions


⇒ Trends

Temporal evolution of the H2O VCD over Germany

0.0E+00

2.0E+22

4.0E+22

6.0E+22

8.0E+22

1.0E+23

1.2E+23

Jan. 96 Jan. 97 Jan. 98 Jan. 99 Jan. 00 Jan. 01 Jan. 02 Jan. 03 Jan. 04

H2O over GermanyWinter: -14.6%Spring: -4.2%Summer: +12.6%Autumn: +4.8%

Winter: strong decrease (-15%) Summer: strong increase (+13%)


Linear trends in H2O and clouds over 8 years as function of latitude (different seasons)

⇒ Trends

-2.0% 0.0% 2.0% 4.0% 6.0% 8.0%

80°N - 55°N

55°N - 35°N

35°N - 10°N

10°N - 10°S

10°S - 35°S

35°S - 55°S

55°S - 80°S

WinterSpringSummerAutumn

Relative change in H2O (mostly clear sky)

0.0% 2.0% 4.0% 6.0% 8.0%

80°N - 55°N

55°N - 35°N

35°N - 10°N

10°N - 10°S

10°S - 35°S

35°S - 55°S

55°S - 80°S

WinterSpringSummerAutumn

Relative change in cloud shielding

Strongest H2O increase: Northern hemisphere: SpringSouthern hemisphere: Autumn


⇒ Future

• Full exploitation of existing data (using e.g. detailed cloud information)

(> 8 years of GOME, > years of SCIA data!!!!)

• Additional species

• Combination of results from different sensors (UV/vis, IR, MW, etc.)

• Detailed comparison with model results, data assimilation

• Scheduled missions and instruments

• Higher spatial and temporal resolution, better sampling rate

=> which resolution do we need?


⇒ Future

• Many ground pixels are (at least partly) covered with clouds• Clouds are typically much brighter than the cloud free scenes (except over ice and snow)

=> Clouds cause largest uncertainties for tropospheric species!

Two dominant effects of clouds:A) Shielding effect for trace gases below cloudsB) Albedo effect for trace gases above clouds(nearly no cloud effect for stratospheric trace gases)


⇒ Future

Possible Cloud correction Scheeme:

Cloud properties

Model(As much as possible)Measurements

-O2 & O4

-intensity (spectral channels & PMD)

-Ring effect

-polarisation

-additionalquantities

-Monte Carlo

-multiplescattering

-full spherical geometry

-Cloud fraction

-Cloud top height

-ground albedo

-optical depth?

-3D-structure?


⇒ Future










⇒ Future Glyoxal as indicatotor of VOC degradation

Glyoxal cross section in the blue spectral range!

Volkamer et al., 2004


⇒ Future










Combination of GOME H2O VCD with H2O profiles from TOVS

⇒ Future

Sensitivity of TOVS H2O observation for different IR wavelengths

Soden and Bretherton, 1996


⇒ Future










1960 1970 1980 1990 2000

Sputnik

Satellites

Weather Satellites

Ozone(BUV)

Ozone(TOMS)

Ozone++(spectra)

UV/vis satellite history

Explorer

TIROS NIMBUS-4

NIMBUS-7

NOAA-9

NOAA-11 NOAA-14

Space shuttle

METEOR-3 Earth-probe

ADEOS

GOME SCIAMACHY

NIMBUS-7

GOME-2 ...

2010

SCIA OMI

⇒ Future


⇒ Future Spatial resolution and sampling rate

40 x 320 km2GOME

SCIA

OMI

40 x 80 km2

30 x 60 (15) km2

13 x 24 (13) km2

Sampling rate:

GOME: ≥ every 3 days

SCIA: ≥ every 6 days

OMI: ≥ every day


⇒ Future










⇒ influence of spat. resolutionStandard Mode (320x40km²): GOME trop. NO2 (1996-2001)

Narrow Mode (80x40km²): GOME trop. NO2 (1996-2001)

*1015

molec/cm2

(Steffen Beirle,

IUP-Heidelberg)


Tropospheric NO2 VCD from GOME narrow mode, Steffen Beirle

⇒ influence of spat. resolution


Tropospheric NO2 VCD from GOME normal mode, Steffen Beirle




SCIAMACHY tropospheric NO2 VCD

SCIAMACHY August 2003

Steffen Beirle, IUP Heidelberg


Conclusions

I hope I could show you that:

• trace gas observations provide a new & exciting viewon atmospheric chemistry and physics

• there are many important applications in future research, especially for the investigation of chemistry/climate relationships

......and finally....


Thanks to the satellite group Heidelberg!

current status and future perspectives of...

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