Abstract
Abstract. We evaluate different sets of high-resolution ozone absorption cross-section data for use in atmospheric ozone profile measurements in the Hartley and Huggins bands with a particular focus on BDM 1995 (Daumont et al. 1992; Brion et al., 1993; Malicet et al., 1995), currently used in our retrievals, and a new laboratory dataset by Birk and Wagner (2018) (BW). The BDM cross-section data have been recommended to use for retrieval of ozone profiles using spaceborne nadir-viewing backscattered ultraviolet (BUV) measurements since its improved performance was demonstrated against other cross-sections including Bass and Paur (1985) (BP) and those of Serdyuchenko et al. (2014) and Gorshelev et al. (2014) (SER) by the “Absorption Cross-Sections of Ozone” (ACSO) activity. The BW laboratory data were recently measured within the framework of the European Space Agency (ESA) project SEOM-IAS (Scientific Exploitation of Operational Missions – Improved Atmospheric Spectroscopy Databases) to provide an advanced absorption cross-section database. The BW cross-sections are made from measurements at more temperatures and in a wider temperature range than BDM, especially for low temperatures. Relative differences of cross-sections between BW and BDM range from ∼2 % at shorter UV wavelengths to ∼5 % at longer UV wavelengths at warm temperatures. Furthermore, these differences dynamically increase by up to ±40 % at cold temperatures due to no BDM measurements having been made below 218 K. We evaluate the impact of using different cross-sections on ozone profile retrievals from Ozone Monitoring Instrument (OMI) measurements. Correspondingly, this impact leads to significant differences in individual ozone retrievals by up to 50 % in the tropopause where the coldest atmospheric temperatures are observed. Bottom atmospheric layers illustrate the significant change of the retrieved ozone values, with differences of 20 % in low latitudes, which is not the case in high latitudes because the ozone retrievals are mainly controlled by a priori ozone information in high latitudes due to less photon penetration down to the lower troposphere. Validation with ozonesonde observations demonstrates that BW and BDM retrievals show altitude-dependent bias oscillations of similar magnitude relative to ozonesonde measurements, much smaller than those of both BP and SER retrievals. However, compared to BDM, BW retrievals show significant reduction in standard deviation, by up to 15 %, especially at the coldest atmospheric temperatures. Such improvement is achieved mainly by the better characterization of the temperature dependence of ozone absorption.
Highlights
Accurate knowledge of the absorption cross-sections of ozone and their temperature dependence is essential for highly accurate measurements of atmospheric ozone (Orphal et al, 2016) as well as other trace gases affected by the strong ozone absorption such as BrO, NO2, SO2 and CH2O (e.g., Seo et al, 2019; Theys et al, 2017)
The BP dataset is no longer recommended for any atmospheric ozone measurements (Orphal et al, 2016) but still used to keep the long-term consistency of ground-based Dobson– Brewer total ozone records and spaceborne Total Ozone Mapping Spectrometer (TOMS)/Ozone Monitoring Instrument (OMI) total ozone records (McPeters et al, 2015)
This paper evaluates the recently measured laboratory highresolution BW 2018 ozone cross-section data within the framework of the European Space Agency (ESA) SEOM-IAS project to see whether or not the current recommendation should be changed for improving ozone profile retrievals from UV measurements
Summary
Accurate knowledge of the absorption cross-sections of ozone and their temperature dependence is essential for highly accurate measurements of atmospheric ozone (Orphal et al, 2016) as well as other trace gases affected by the strong ozone absorption such as BrO, NO2, SO2 and CH2O (e.g., Seo et al, 2019; Theys et al, 2017). The BP dataset is no longer recommended for any atmospheric ozone measurements (Orphal et al, 2016) but still used to keep the long-term consistency of ground-based Dobson– Brewer total ozone records and spaceborne Total Ozone Mapping Spectrometer (TOMS)/Ozone Monitoring Instrument (OMI) total ozone records (McPeters et al, 2015) These cross-sections were included in the 2004 edition of the high-resolution transmission molecular absorption database (HITRAN) (Rothman et al, 2005) and remained unchanged in subsequent editions including HITRAN2016 (Gordon et al, 2017). In Liu et al (2007), these three datasets were thoroughly assessed to find the most suitable cross-sections for GOME ozone profile retrievals (290–307 and 325–340 nm) As a result, they recommended using the BDM for ozone profile retrievals due to much smaller fitting residuals and better agreement with ozonesonde measurements.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
