Synergistic Use of Satellite Data with the Global Chemistry-Transport Model GEOS-CHEM: Formaldehyde column over Europe as a Proxy for
Biogenic Emissions and CTM Validation using Satellite Data

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

Guido Visconti

Center of Excellence Integration of remote sensing techniques and
numerical techniques to forecast severe weather
Università degli Studi - L'Aquila, 67010 Coppito (L'Aquila), Italy
Tel: +39 862 433075
Fax: + 39 862 433089

Objective 1

We intend to use data analysis from GOME to retrieve formaldehyde (HCHO) data. Formaldehyde is a very important intermediate oxidation product of VOC of anthropogenic and biogenic origin. Preliminary results suggest that the formaldehyde column over Europe is underestimated by the state-of-the-art chemistry and transport model GEOS-CHEM with respect to GOME column (Figure 1), possibly indicating biases in model VOC emissions.

The HCHO column could be also used to estimate the sources of isoprene (a major biogenic VOC) in the European continent, at least in Eastern Europe where the isoprene contribution to the HCHO column seem to be predominant from model results
(Figure 2 ). These sources could be compared with existing inventories and with those obtained during measurement campaign.

Objective 2

We intend to develop new method to validate Chemical Transport Models and to assess their capability to reproduce natural variability. Following a technique outlined for the thermal Earth radiation we propose to compare the radiative covariance from synthetic spectra from models with covariance obtained from observed spectra. For a spectra the covariance is calculated between the different spectral channels and from that EOFs are obtained. The principal EOF components will give a quantitative estimation of the variability. Chemical fields from CTM will be used to calculate synthetic spectra and then EOF. These will be compared with real spectra obtained in the same condition. In particular we have in mind in data from SCIAMACHY.

Acknowledgement for GOME data: P. Palmer and M. Fu (Harvard University), K. Chance and T.P. Korosu (Harvard-Smithsonian Center for Astrophysics).

 

Figure 1. Upper panel: monthly mean formaldehyde column over Europe as retrieved from the GOME instrument onboard the ERS-2 satellite during July 1997. Middle panel: same as above but from model results (GEOS-CHEM). Bottom panel: monthly mean isoprene emission in the model for July 1997. Isoprene is the most important biogenic VOC and a major precursor of HCHO.

Figure 2. Formaldehyde column ratio between two model runs: the first with isoprene emissions switched off (no ISOP Emiss.), the second with anthropogenic emissions switched off (no ANTHRO Emiss.). Blue colours indicate a prevalence of isoprene emissions in controlling the HCHO column, dark red a prevalence of anthropogenic emissions, yellow-orange an intermediate condition.

Time Schedule

 

2004

2005

2006

2007

2008

2009

Objective 1

***

***

***

**

**

 

Objective 2

***

***

**

**

**

**

Approximate manpower and cost

 

2004

2005

2006

2007

2008

2009

Personnel/man-years

3

3

3

3

2

1

Yearly cost (kEuro)

90

90

90

90

60

30

Likely Funding Agencies

Italian Space Agency, European Community

Co-workers

Gabriele Curci

Center of Excellence Integration of remote sensing techniques and numerical techniques to forecast severe weather, Università degli Studi L'Aquila, 67010 Coppito, Italy

Gianluca Redaelli

Department of Physics, Università degli Studi L'Aquila, 67010 Coppito, Italy

Barbara Grassi

Department of Physics, Università degli Studi L'Aquila, 67010 Coppito, Italy

 


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