An updated version of a gap-free monthly mean zonal mean ozone database

Abstract

Abstract. An updated and improved version of a global, vertically resolved, monthly mean zonal mean ozone database has been calculated -hereafter referred to as the BSVertOzone (Bodeker Scientific Vertical Ozone) database. Like its predecessor, it combines measurements from several satellite-based instruments and ozone profile measurements from the global ozonesonde network. Monthly mean zonal mean ozone concentrations in mixing ratio and number density are provided in 5 • latitude bins, spanning 70 altitude levels (1 to 70 km), or 70 pressure levels that are approximately 1 km apart (878.4 to 0.046 hPa). Different data sets or "tiers" are provided: Tier 0 is based only on the available measurements and therefore does not completely cover the whole globe or the full vertical range uniformly; the Tier 0.5 monthly mean zonal means are calculated as a filled version of the Tier 0 database where missing monthly mean zonal mean values are estimated from correlations against a total column ozone (TCO) database. The Tier 0.5 data set includes the full range of measurement variability and is created as an intermediate step for the calculation of the Tier 1 data where a least squares regression model is used to attribute variability to various known forcing factors for ozone. Regression model fit coefficients are expanded in Fourier series and Legendre polynomials (to account for seasonality and latitudinal structure, respectively). Four different combinations of contributions from selected regression model basis functions result in four different Tier 1 data sets that can be used for comparisons with chemistry-climate model (CCM) simulations that do not exhibit the same unforced variability as reality (unless they are nudged towards reanalyses). Compared to previous versions of the database, this update includes additional satellite data sources and ozonesonde measurements to extend the database period to 2016. Additional improvements over the previous version of the database include the following: (i) adjustments of measurements to account for biases and drifts between different data sources (using a chemistry-transport model, CTM, simulation as a transfer standard), (ii) a more objective way to determine the optimum number of Fourier and Legendre expansions for the basis function fit coefficients, and (iii) the derivation of methodological and measurement uncertainties on each database value are traced through all data modification steps. Comparisons with the ozone database from SWOOSH (Stratospheric Water and OzOne Satellite Homogenized data set) show good agreement in many regions of the globe. Minor differences are caused by different bias adjustment procedures for the two databases. However, compared to SWOOSH, BSVertOzone additionally covers the troposphere. Version 1.0 of BSVertOzone is publicly available at https://doi.org/http://doi.org/10

Simplified SAGE II ozone data usage rules

“…CC BY 4.0 License. were applied to the SAGE II ozone data set before being used to generate a homogenized satellite record of vertically resolved ozone data sets (Davis et al, 2016;Hassler et al, 2008Hassler et al, , 2018. A long-term, latitudinally and vertically resolved ozone database is required as input to climate models that do not have the ability to include a fully coupled stratospheric chemistry scheme (Hassler et al, 2018).…”

“…were applied to the SAGE II ozone data set before being used to generate a homogenized satellite record of vertically resolved ozone data sets (Davis et al, 2016;Hassler et al, 2008Hassler et al, , 2018. A long-term, latitudinally and vertically resolved ozone database is required as input to climate models that do not have the ability to include a fully coupled stratospheric chemistry scheme (Hassler et al, 2018). Both Davis et al (2016) and Hassler et al (2018) applied around seven rules that are mainly based on previous studies by Wang et al (2002) with the modifications outlined in the SAGE II version 7.0 release notes.…”

“…trends that are derived from the SAGE II observations. Here we will discuss data usage rules that have been applied in screening SAGE II ozone data before their use in the generation of homogeneous long-term ozone data sets as described in Froidevaux et al (2015); Hassler et al (2008Hassler et al ( , 2018 and Davis et al (2016). The data rules outlined below were derived by others and are the most predominately rules found in the literature and are commonly applied usage rules.…”

“…Wang et al (2002) suggested to remove all data if error is greater than 300 %. This rule was later adapted to only exclude ozone values above 35 km if error is bigger than 300 % (Froidevaux et al (2015); Davis et al (2016); Hassler et al (2018), SAGE II v7 release notes).…”

Climate feedbacks in the Earth system and prospects for their evaluation

“…An important point is that radiative feedbacks strongly depend on details in the three-dimensional patterns, in particular its vertical structure, because the crucial longwave radiative feedback component is dominated by ozone changes in the vicinity of the tropopause (Dietmuller et al, 2014;Marsh et al, 2016;Nowack et al, 2015). The first attempts to derive trends in the latitudinal and vertical distribution of observed ozone change have been made from aircraft and radiosonde data (Poberaj et al, 2009) and by combining satellite data with a regression model (Cionni et al, 2011;Hassler et al, 2018;Hassler et al, 2013). As the number and the length of these observed time series increase, the combination of analysis methods will become more appealing (Ball et al, 2017) and advanced analysis methods (e.g.…”