SO2 data and alert service

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Product information

Introduction
 
Slant column density vs.
vertical column density
Geographic regions
Data presentation
and delivery
Solar Zenith Angle
What is the Dobson Unit?
 
Slant column retrieval
Background correction
Reference spectrum
Cloud cover fraction
 
Near-real time service
Criteria for exceptional
SO2 concentrations
 
Air-mass factor using
look-up tables
Air-mass factor using a
chemistry transport model
SO2 column from OMI
 
Time period of
available data
Data format specification
Data and Service
version history
Validation of the
data products
South Atlantic Anomaly
 
Downloading
data & image files
Documentation
References
Acronyms
Acknowledgments

 
NOTE:   This is the OLD product info. Some parts of it are no longer up to date, while other parts are missing -- see the remark on the main product info page.

Air Mass Factor using a Chemistry Transport Model

There are two approaches taken to convert the SO2 slant column density, retrieved with a DOAS technique, into a vertical column density. Both approaches use an Air-Mass Factor (AMF). This page describes the use of a chemistry transport model to obtain this air mass factor.

 
In this approach the retrieval of the VCD for SO2 will be based on a combined retrieval/modelling approach, similar to the approach for some other trace gases (such as formaldehyde, HCHO). The main motivation for this new approach is to improve the accuracy of the retrieval. A chemistry-transport model (TM4), driven by high-quality meteorological fields from ECMWF, will provide best-guess profiles of SO2, based on the latest emission inventories, atmospheric transport, photochemistry and wet/dry removal processes.

These model forecast fields will be collocated with the satellite (GOME, SCIAMACHY, OMI) observations, and the radiative transfer modelling in the retrieval will be performed based on the model trace gas profile and temperature profiles. The retrieval is coupled to cloud top height and cloud fraction retrievals derived from the satellite data, and the retrieval will be coupled to high quality albedo maps.
 

NOTE

This approach is currently not under evaluation.
Possibly it will be picked up again at a later stage.

 

 

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