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Data and Services version history

The data files, and with that the Services, have been given a version number, in order to track changes in the different parts of the processing. Stricktly speaking that number only applies to the data files based on SCIAMACHY and GOME-2 measurements, not for OMI data as the production of OMI data is done by NASA/NOAA. This means that the addition of OMI data or changes therein does not change the version number. For that reason a separate 2-digit "service version number"   S-##   is used.

 
The version number of the processing looks like this:   A.B.C

where   A.B   represents the version of the slant column retrieval and the notification system, and   .C   the version of the AMF-based vertical columns; if   C   is zero or absent, no vertical columns (VCDs) are available. See further down for a list of VCD numbers.

The table below gives an overview of the version numbers and what was added/done for that version. Some additions to the website of the data record, which do not merit an increase of the version number, are added in the table for the benefit of the visitor who wants to track changes. Also additions of and changes to the OMI data are mentioned in the table.

version date history
1.0.3
S-08
February 2008 Near-real time images of GOME-2 based SO2 data are made available, using a preliminary background correction (compensating mainly for an offset). Once more experience is gained with GOME-2 data, the background correction has been improved, and the data are available.
1.0.3
S-07
January 2008 The colour scale of the SO2 vertical column plots in the archive and NRT services has been adapted: it now ends at 2 DU (was 3), so that large SO2 values are better visible.
1.0.3
S-06
November 2007 Near-real time images of OMI SO2 data are made available; the NRT data itself is not available for third parties.
1.0.3
S-05
August 2007 Introduction of a new, improved background correction in the processing, in particular to try to get rid of most of the of artifacts at high SZA, giving rise to "false notifications" due to the interference between the absorption signals of SO2 and ozone. At the same time VCDs are included in the processing, the data format of the files has been adapted and the presentation on the web site has been improved.

A separate page gives a full overview of the new features of version 1.0.3.

Initially, the archive covers the months January to June 2007; more data is added later.
The near-real time processing and notification service were started on 16 August; the preceeding days of that month were processed by hand as if in NRT.

===> History of previous versions

 

SCIAMACHY data version

The SCIAMACHY data, from which the SO2 concentrations are derived, comes in different versions, depending on improvements in the official data processor and reprocessing of older data. The following table lists the software versions of the SCIAMACHY data used for the SO2 retrieval available here. The cloud cover data used is FRESCO v5 and v5.1 (the latter starts in Dec. 2007).

version data period
5.04 2004 :   September -- December
2005 :   January -- December
2006 :   January -- 22 May
6.02 2006 :   22 May -- December
2007 :   January -- 19 July
6.03 2007 :   19 July -- present

 

OMI data version

The OMI data, from which the SO2 concentrations are derived by NASA/NOAA, comes in different versions, depending on improvements in the official data processor and reprocessing of older data. The following table lists the software versions of the OMI data used for the SO2 retrieval available here; see this page at the NASA website for details.

version data period
002 17 August 2004 -- present

 

GOME-2 data version

The GOME-2 data, from which the SO2 concentrations are derived by EUMETSAT/DLR/BIRA, comes in different versions, depending on improvements in the official data processor and reprocessing of older data. The following table lists the software versions of the GOME-2 data used for the SO2 retrieval and plots.

version data period
GDP_4.4 March 2010 -- present
GDP_4.3 January 2007 -- February 2010

 

AMF & VCD data version

The last figure (C) of the data version number listed above refers to the version of the AMF-based vertical columns (VCDs) for the SCIAMACHY data; if   C   is absent it has value zero. The following table gives an overview of the versions.

C date info
0 -- No AMF and VCD are computed.
1 Nov. 2005

was never
implemented

A preliminary version of AMF tables, using three different vertical SO2 profiles, based on yearly average SO2 data from anthropogenic activities ("air pollution profiles), for different SO2 concentration regimes. This was used for testing; results have not been made available.
2 May 2006

was never
implemented

Similar to version '1', but with an extra vertical SO2 profile for very weak SO2 concentrations (the "no pollution case"), and one AMF table for each season. These tables have not been used.
3 March 2007

implemented:
August 2007

AMF look-up tables with vertical profiles of an SO2 plume of 1 km thick at different altitudes for two types of SO2 concentrations: low (around 3 DU) and high (around 30 DU). For the processing three plume height are selected and used for computing the VCD, while one of these is used for the plots.

A separate page provides more information.

 
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