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Stratospheric NO2 data from SCIAMACHY
Introduction Station Data Disclaimer Climatology Contact Links
Introduction:
For validation purposes, a time series of daily SCIAMACHY NO2 columns (August 2002 - July 2010) within a 200 km radius has been created which can be downloaded in ASCII format for all SCIAMACHY validation stations.
For data before SCIAMACHY operations please have a look at our GOME pages or go directly to the GOME NO2 data page.
SCIAMACHY
stratospheric NO2 columns over stations Version 2.1:
Existing data have been updated to V2.1 on June 7, 2007. The differences to version 2.0 are
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fix of a bug in the time stamp close to the date change (affects only few stations and only the time stamp, not the columns)
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limitation to lv1 data which improves consistency but reduces the coverage slightly
The old version 1.5 data have been replaced by a new data release V2.0 on November 20, 2006. The differences to version 1.5 are
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much more data in 2002 and 2003 as consolidated SCIAMACHY lv1 files were used
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less effects of drift as daily solar spectra have been used
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no offset is applied to the slant columns any more leading to significant improvement compared to ground-based measurements
Please also read the disclaimer.
The data format is plain ASCII with 26 header lines starting with a '*' character followed by the lines with the data organized in 10 columns separated by blanks:
column 1: fractional day of year 1993 UT
column 2: fractional day of year UT
column 3: solar zenith angle [°]
column 4: daily average slant column of NO2 [molec cm-2] in 200 km radius
column 5: daily average vertical column of NO2 [molec cm-2] in 200 km radius
column 6: daily minimum slant column of NO2 [molec cm-2] in 200 km radius
column 7: daily minimum vertical column of NO2 [molec cm-2] in 200 km radius
column 8: daily maximum slant column of NO2 [molec cm-2] in 200 km radius
column 9: daily maximum vertical column of NO2 [molec cm-2] in 200 km radius
column 10: average chisquare of retrieval
The full data set with all individual overpasses can be downloaded as a zip-file (> 170 MBytes) here.
Disclaimer:
SCIAMACHY NO2 columns provided on this page are a scientific product created at the University of Bremen and based on the operational lv0 and uncalibrated lv1-spectra provided by DFD/DLR Oberpfaffenhofen and ESRIN/ESA. They are not related to the operational SCIAMACHY lv2-products distributed by DFD/DLR that also contain NO2 columns. Although the two SCIAMACHY NO2 data products agree qualitatively, the differences are significant, and thorough validation will have to be performed of both products.
The NO2 columns in the files provided on this page are total columns assuming a stratospheric profile (US standard atmosphere with the troposphere set to 0). Wherever there is substantial NO2 in the troposphere (for example in polluted regions such as Germany), the columns will exceed the real stratospheric ones and are not very accurate.
As only part of the SCIAMACHY measurements is available to us at this time, all time series have substantial gaps that will be filled as more data is delivered by ESA. At the same time, some data are received several times and therefore have too much weight in the averages. As stratospheric NO2 fields are relatively smooth, this should usually not impact the results very much. In the next data version, duplicates will be removed.
To decontaminate the SCIAMACHY IR detectors, the instrument is heated on a regular basis. During these periods, data quality is reduced and larger errors are to be expected.
Total
NO2 climatology:
SCIAMACHY data from 2003 to 2007 have been averaged on a monthly basis to create a NO2 total column climatology on a 0.125° x 0.125° grid. The data are a combination of the tropospheric columns (see SCIAMACHY tropospheric NO2 page) and the estimate of the stratospheric column derived over the Pacific. More details are given in the readme file included in the archive file with the climatology.
Download: SCIAMACHY total NO2 column climatology (70 MBytes)
Links:
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More on stratospheric NO2 from SCIAMACHY can be found here.
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You might want to check our GOME NO2 page.
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There also are tropospheric NO2 columns from SCIAMACHY available.
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More information on SCIAMACHY can be found here.
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More SCIAMACHY scientific products can be found at the IUP Bremen data archive.
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Many SCIAMACHY related links can be found on the German SCIAMACHY page.
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For information on the satellite and other ENVISAT instruments check the ESA ENVISAT page.
Contact
If you have any questions, comments or data requests, please contact Andreas Richter.