SCIAMACHY Near-infrared Retrieval of CH4, CO2, N2O and CO

A contribution to ACCENT-TROPOSAT-2, Task Group 1

Christian Frankenberg

Institut für Umweltphysik, University of Heidelberg, INF 229 D-69120 Heidelberg
Tel.:  +49-(0)6221 545477
Fax:  +49-(0)6221 546405

Methane and carbon dioxide are the most important greenhouse gases, second only to atmospheric water vapour. Especially the biogeochemical and anthropogenic sources and sinks of CO2 and CH4 have been widely discussed not only in the scientific community. The oxidation of methane also plays an important role in the lifetime of OH radicals. CO can be used as a tracer for anthropogenic fossil fuel emissions as well as for biomass burning. However, there are still large uncertainties in global source strengths. The near infrared channels of SCIAMACHY onboard ENVISAT enable satellite-based worldwide measurements of total columns of these species.

Since CH4 and CO2 are long-lived trace species, their temporal and spatial variations are rather low. Thus, the retrieval algorithm should yield precise vertical columns of the species of interest. To this end, a new iterative DOAS algorithm basing on optimal estimation was developed at Heidelberg. In combination with the new cloud retrieval algorithm, vertical columns can be inferred precisely.

In this project, we propose to develop high quality CH4, CO2 and CO column density data products. Especially global monthly mean maps of these species will increase our knowledge of seasonal cycles and trends of greenhouse gases. We will investigate in detail the influence of clouds and aerosols on the retrieved columns. Furthermore a special focus will be set on the optimisation of the retrieval algorithm. Especially the impact of the atmospheric temperature and pressure profiles as well as uncertainties in the spectroscopic database will be investigated. A comparison with retrieval algorithms from other institutions like IUP Bremen or SRON will also be carried out.

After having retrieved reliable mean monthly maps of the species of interest, the work will be focussed on the scientific interpretation of the results. The spatial and temporal patterns of methane and carbon dioxide columns will provide deeper insight into the processes driving their abundance in the atmosphere.

Time schedule

 

2004

2005

2006

2007

Algorithm optimisation

*

 

 

 

Dependence on clouds and aerosols

*

*

*

*

Creation of global mean maps

*

*

*

*

Specific case studies

 

*

*

*

 Approximate manpower and cost

 

2004

2005

2006

2007

Personnel / person-years

0.4

0.4

0.4

0.4

Yearly cost (kECU)

5

5

5

5

Likely funding agencies

BMBF, EU

Co-workers

Michael Grzegorski

Suniti Sanghavi

Thomas Wagner

Institut für Umweltphysik, University of Heidelberg
INF 229, D-69120 Heidelberg
Germany

 

 


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