Product information
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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.
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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 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
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February 2008
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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
will be improved, and the data will also be made available.
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1.0.3
S-07
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January 2008
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The colour scale of the SO2 vertical column plots in the archive
has been adapted: it now ends at 2 DU (was 3), so that large
SO2 values are better visible (the SO2 slant column values are
usualy larger and their colour scale ends at 3 DU). The colour
scale of the NRT processing is adapted on 07 Jan.
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1.0.3
S-06
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November 2007
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Near-real time images of OMI SO2 data are made available; the NRT data
itself is not available for third parties. An archive of the OMI data will
follow later.
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1.0.3
S-05
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August 2007
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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 alerts" 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 alert service were started on 16 August;
the preceeding days of that month were processed by hand as if in NRT.
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===> History of previous versions
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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
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| 6.02 |
2006 : 22 May -- December
2007 : January -- 19 July
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| 6.03 |
2007 : 19 July -- present
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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
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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.
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| 1 |
Nov. 2005
was never
implemented
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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.
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| 2 |
May 2006
was never
implemented
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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.
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| 3 |
March 2007
implemented:
August 2007
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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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