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.
Impact of using a new ultraviolet ozone absorption cross-section dataset on OMI ozone profile retrievals
