The CAMS reanalysis of atmospheric composition

Antje Inness,Melanie Ades,Anne-Marlene Blechschmidt,Zak Kipling,Martin Suttie,Vincent Huijnen,Jérôme Barré,Anna Benedictow,Mark Parrington,Johannes Flemming,Miha Razinger,Luke Jones,Richard Engelen,Henk Eskes,Samuel Rémy ,S Massart ,Mıchael Schulz ,Juan J Dominguez ,Anna Agustı́-Panareda ,Vincent‐Henri Peuch

doi:10.5194/acp-19-3515-2019

Abstract

Abstract. The Copernicus Atmosphere Monitoring Service (CAMS) reanalysis is the latest global reanalysis dataset of atmospheric composition produced by the European Centre for Medium-Range Weather Forecasts (ECMWF), consisting of three-dimensional time-consistent atmospheric composition fields, including aerosols and chemical species. The dataset currently covers the period 2003–2016 and will be extended in the future by adding 1 year each year. A reanalysis for greenhouse gases is being produced separately. The CAMS reanalysis builds on the experience gained during the production of the earlier Monitoring Atmospheric Composition and Climate (MACC) reanalysis and CAMS interim reanalysis. Satellite retrievals of total column CO; tropospheric column NO2; aerosol optical depth (AOD); and total column, partial column and profile ozone retrievals were assimilated for the CAMS reanalysis with ECMWF's Integrated Forecasting System. The new reanalysis has an increased horizontal resolution of about 80 km and provides more chemical species at a better temporal resolution (3-hourly analysis fields, 3-hourly forecast fields and hourly surface forecast fields) than the previously produced CAMS interim reanalysis. The CAMS reanalysis has smaller biases compared with most of the independent ozone, carbon monoxide, nitrogen dioxide and aerosol optical depth observations used for validation in this paper than the previous two reanalyses and is much improved and more consistent in time, especially compared to the MACC reanalysis. The CAMS reanalysis is a dataset that can be used to compute climatologies, study trends, evaluate models, benchmark other reanalyses or serve as boundary conditions for regional models for past periods.

Highlights

The European Centre for Medium-Range Weather Forecasts (ECMWF) has been producing atmospheric composition (AC) forecasts and analyses for over a decade
Analysis fields for O3, CO, NO2 and aerosol optical depth (AOD) from CAMS reanalysis (CAMSRA) are compared to fields from CAMS interim reanalysis” (CIRA) and MACC reanalysis (MACCRA) to highlight some of the improvements in CAMSRA and to point out some of the problems potential users should be aware of
We start by looking at total column O3 (TCO3), which is dominated by stratospheric O3, and look at tropospheric and surface O3, which are more relevant for air quality users

Summary

Introduction

The European Centre for Medium-Range Weather Forecasts (ECMWF) has been producing atmospheric composition (AC) forecasts and analyses for over a decade. In GEMS, ECMWF’s Integrated Forecast System (IFS) was extended to allow for the data assimilation and modelling of aerosols, chemically reactive gases and greenhouse gases, and the first daily forecasts of reactive gases such as carbon monoxide (CO) and tropospheric ozone (O3) were made public in May 2007 (Flemming et al, 2017a). This was followed a year later, in July 2008, by the real-time data assimilation of aerosol optical depth (AOD; Benedetti et al, 2009) and selected reactive gases (Inness et al, 2013) in the daily GEMS system. The AC system was further developed in the earlier Monitoring Atmospheric Composition and Climate (MACC) projects

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Conclusion