Better SF₆ global distributions

The figures above show the retrieved SF₆ altitude/latitude cross sections, average over the year 2011, for the same spectral data version (version 5), but applying different spectroscopic absorption cross sections in the retrieval procedure. The left, older data version shows the retrieval results based on absorption cross sections measured in the laboratory by Varanasi and co-workers in 1994. The new data version on the right shows the retrieval results obtained with novel measurements of SF₆ absorption cross-sections by J.J. Harrison (to be published).

Besides new data on SF₆, Harrison provided also absorption cross sections of CFC-11 (Harrison, 2018) measured for the band in the vicinity of the SF₆ signature for the first time in his lab. Besides the absorption cross sections of SF₆ and CFC-11, all other details of the retrieval settings have been kept the same. The new retrieval results, transformed into stratospheric age of air data, agree much better with reference measurements not depending on spectroscopic information than the previous data version. The comparison demonstrates how strongly remote sensing data depend on laboratory measurements of high accuracy.

For more information see: https://meetingorganizer.copernicus.org/EGU2020/EGU2020-2660.html