Stratospheric NO2 data from SCIAMACHY
For validation purposes, a time series of all daily SCIAMACHY NO2 columns (August 2002 - April 2012) 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. There also is a similar page based on GOME-2 stratospheric data which provides much better spatial coverage and continues after April 8, 2012 when ENVISAT ceased operation.
Existing data have been updated to V2.1 on June 7, 2007. The differences to version 2.0 are
The old version 1.5 data have been replaced by a new data release V2.0 on November 20, 2006.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
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.
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.
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)
If you have any questions, comments or data requests, please contact Andreas Richter.
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