1. Introduction

The Tropospheric Ozone Assessment Report (TOAR) activity of the International Global Atmospheric Chemistry (IGAC) organisation (see https://igacproject.org/activities/TOAR) is collecting surface ozone measurements and related data from all over the world in a central database at Forschungszentrum Jülich, Germany. It currently runs in its second phase, TOAR-II 2020-2024, https://igacproject.org/activities/TOAR/TOAR-II (in our context denoted as TOAR V2, 1). The purpose of collecting this data is to provide globally consistent metrics for analyses of health, vegetation, and climate impacts from ozone air pollution. The database is exposed via a REST API and graphical web services which allow users to visualise data and compare them with other data sets and model observations. We collect data from cooperating data centres, harmonise it, and check its quality before adding it to the TOAR database.

This data submission guide is intended for individual data providers who wish their measurements to be added to the TOAR database. In general, the TOAR data team is always willing to discuss the modalities of data submission. If you are planning to deliver a large amount of data to TOAR, please get in contact with the data centre team before preparing any data files as we may be able to accommodate other formats than the one described in this guide and can thus save you unnecessary work. Specifically, if you have your data already formatted as netcdf files or in NASA AMES format, we can easily accept these as well and would then only ask you to provide us with the additional metadata in a stations.csv file. If your data consists of a small number of files, we ask you to adhere to the guidelines described here as closely as possible. The more your data format differs from our template, the more likely we will not be able to process your data and it will thus be lost to the TOAR effort. In case of doubts or ambiguities we will get back to you to sort out any metadata or data issues.

The ASCII format described in this document is meant to facilitate processing of the submitted atmospheric data for inclusion in the TOAR surface station database at Jülich. But it is also designed to make the data submission as easy as possible for you as the data provider. The header will contain all necessary metadata information, and the data format shall make it easy for us to interpret your data with respect to the time of measurement and the measurand values (usually these will be ozone mixing ratios or concentrations). Please note that the scope of TOAR-II has been expanded to also include the analysis of a small set of ozone precursors and related variables (PM2.5 and meteorological information). If you have problems adhering to the TOAR data format, please contact the TOAR data team to find a solution.

The data can be submitted online at https://toar-data.org/contribute/#timeseries or you can send us suitably formatted data files as email attachment or deposit them in a shared folder. Note that we can also store additional documentation about the station(s) at which you perform your measurements in the TOAR database. If you wish to provide URLs, PDF documents or images which further document your measurement site(s), please let us know.

Please make sure to give us your explicit consent that you agree with publication of your data under the CC-BY 4.0 license (see section 2 for details) and that you allow us to curate your data as described in detail in processing-workflow.



TOAR phase I ran 2014-2019; in our context it is TOAR V1