GOMOS Level2 algorithm evolution studies

Abstract : The GOMOS (Global Ozone Monitoring by Occultation of Stars) spectrometer on Envisat measured more than 860 000 ozone profiles during its ten years of life. These measurements cover all latitudes and extent from the troposphere up to the mesosphere. The best data quality is obtained from the nighttime measurements and these measurements have been used to create ozone climatologies and times series. In addition to ozone, also NO2, NO3, H2O, O2, and aerosol extinction profiles are retrieved from GOMOS spectrometer data. High resolution temperature profiles are determined from the time delay of signals from two fast photometers. GOMOS measurements of NO2 and NO3 have provided first night climatologies of these strongly diurnally varying constituents. In the polar areas NO2 observationshave shown how energetic particle precipitation interacts with the middle atmosphere. Aerosol extinction data and photometer signals have been used to monitor polar stratospheric clouds and mesospheric noctilucent clouds. In the ESA’s GOMOS Level 2 algorithm evolution studies-project we aim at improving the quality of GOMOS products and increase their value in the following way: 1) Improve the GOMOS ozone retrieval in the upper­ troposphere-lower stratosphere region where a large bias between ozone from GOMOS and ground based instruments is evident. The methods tested are a further development of the operational algorithm and a new one-step retrieval algorithm. 2) The retrieval of H2O and O2 from IR-bands has turned out to be challenging. With the change of the retrieval algorithm and developing the wavelength assignment we try to improve the quality of H2O and O2 results. 3) Light emitted by stars and transmitted through the Earth’s atmosphere to GOMOS UV-visible and IR wavelength detectors include fingerprints from additional minor gases not found in the operational GOMOS products. The poor signal-to-noise ratio does not allow retrieval of these gases from individual occultations, but averaging several occultations these fingerprints become visible. A new GOMOS product of averaged transmissions will be generated. 4) We aim to facilitate the use of GOMOS products by creating user-friendly data sets from original GOMOS Level 2 profile data and by generating new altitude gridded products for ozone, NO2, NO3 aerosols, H2O and O2.
Document type :
Poster communications
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Submitted on : Friday, May 6, 2016 - 8:42:20 PM
Last modification on : Tuesday, May 14, 2019 - 11:09:00 AM

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  • HAL Id : insu-01312529, version 1

Citation

Erkki Kyrölä, Janne Hakkarainen, Viktoria Sofieva, Johanna Tamminen, Iolanda Ialongo, et al.. GOMOS Level2 algorithm evolution studies. Living Planet Symposium 2016, May 2016, Prague, Czech Republic. ⟨insu-01312529⟩

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