Novel Techniques for the Retrieval of Tropospheric Composition from Space

A contribution to ACCENT-TROPOSAT-2, Task Group 3

Paul S. Monks

EOS Group, Departments of Chemistry and Physics, University of Leicester,
Leicester, LE1 7RH, UK.
Tel.: +44 (0) 116 252 2141
Fax : +44 (0) 116 252 3789

The University of Leicester EOS group has an interdisciplinary research program looking at the measurement and interpretation of data from EO systems for application to science issues in relation to tropospheric composition. In the main, the work will focus around novel techniques for the retrieval of tropospheric composition from space coupled to integration of synergistic satellite data sets for understanding tropospheric processes.  These activities span a number of the AT 2 task groups.  The primary contributions will centre on

The determination of the effect of changes in greenhouse gas concentrations on the Global Earth Radiation budget (Task Group 2). The objectives of this work are to investigate the role of greenhouse gases in the Earth’s radiation budget using radiative transfer modelling, to asses how greenhouse gas measurements from satellite (in particular from SCIAMACHY) can improve our knowledge of the radiation budget and to compare model calculations with satellite borne measurements of the radiation budget from the GERB instrument (see Figure 1).

Figure 1:  Modelled weighting functions for up- and down-welling solar and thermal flux at the surface (solid lines) and at the top of the atmosphere (dashed lines), illustrating the sensitivity of the radiation budget on atmospheric parameters at different altitudes.

There is growing interest in the potential to measure greenhouse gases from space. The ability to retrieve CO2 and CO from SCIAMACHY NIR data using Weighting-Function Modified (WFM) DOAS and optimal estimation (Task Group 1) will be assessed. This technique is in early stages, but has the potential to produce novel measurements of CO2 and CO from data in the NIR.

The development of residual methods for retrieval of tropospheric composition from spac, using synergistic measurements from multiple satellite instruments (e.g. GOME, TOVS, MIPAS, TOMS and SCIAMACHY), the validity of retrieving trace gas concentrations, in particular ozone, using residual methods will be assessed (Task Group 2). The MIPAS ozone profile down to 12 km will be validated against data from the SHADOZ network.

The application of Concurrent Multi-Axis DOAS (CMAX) measurements of ozone and NO2 to satellite validation will be explored (Task Group 3). The effect of the spatial variability of stratospheric ozone and NO2 on ground-based measurements will be investigated particularly with respect to the implications for satellite validation activities. The MAX-DOAS instrument installed in Leicester currently recording one minute time resolved dataset of tropospheric and stratospheric NO2 and ozone will be used (See Figure 2). Comparisons with tropospheric and stratospheric satellite measurements will be part of the ongoing instrument characterisation.

Figure 2:  Slant Columns of nitrogen dioxide as measured by the Leicester CMAX-DOAS system, showing the detection of separate air masses (by resolving individual peaks), and providing an indication of dynamical motion (by the temporal shift in peaks)

Development of novel concepts for measuring the troposphere from space. As an underpinning activity within AT2, the development of new satellite observing strategies for the troposphere such as GEOSCIA for the measurement of the troposphere from geostationary orbit will be investigated. Mission concepts will be developed and tested for the measurement of high spatial and temporal resolution tropospheric composition data from space. The activities to be included in AT2 will be in addition to the developing mission concepts to develop and test the relevant science case, develop technical and scientific trade-off matrices, test prototype hardware and contribute to ESA studies (e.g. PROMOTE and CAPACITY) in relation to this topic.

 Time Schedule

 

2004

2005

2006

2007

2008

Activity 1

***

***

**

**

*

Activity 2

 

 

 

 

 

Activity 3

***

***

***

*

*

Activity 4

***

**

*

*

*

Approximate manpower and cost

 

2004

2005

2006

2007

2008

Personnel / man years

2.0

2

1.0

0.5

0.25

Yearly Cost (kECU)

30,000

30,000

15,000

7,500

3,750

Likely Funding Agencies

CEC, UK national funding bodies (e.g. NERC, EPSRC, BNSC) and ESA

Co-Workers

Gary Corlett                 

Udo Frieß                   

Roland Leigh                

Address: Space Research Centre
Department of Physics and Astronomy
University of Leicester
Leicester, LE1 7RH, UK.

 


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