The CAMS reanalysis of atmospheric composition

Abstract

Abstract. The Copernicus Atmosphere Monitoring Service (CAMS)\nreanalysis is the latest global reanalysis dataset of atmospheric\ncomposition produced by the European Centre for Medium-Range Weather\nForecasts (ECMWF), consisting of three-dimensional time-consistent atmospheric\ncomposition fields, including aerosols and chemical species. The dataset\ncurrently covers the period 2003–2016 and will be extended in the future by\nadding 1\xa0year each year. A reanalysis for greenhouse gases is being\nproduced separately. The CAMS reanalysis builds on the experience gained\nduring the production of the earlier Monitoring Atmospheric Composition and\nClimate (MACC) reanalysis and CAMS interim reanalysis. Satellite retrievals\nof total column CO; tropospheric column NO2 ; aerosol optical depth (AOD); and\ntotal column, partial column and profile ozone retrievals were assimilated\nfor the CAMS reanalysis with ECMWF s Integrated Forecasting System. The new\nreanalysis has an increased horizontal resolution of about 80\u2009km and\nprovides more chemical species at a better temporal resolution (3-hourly\nanalysis fields, 3-hourly forecast fields and hourly surface forecast\nfields) than the previously produced CAMS interim reanalysis. The CAMS\nreanalysis has smaller biases compared with most of the independent ozone,\ncarbon monoxide, nitrogen dioxide and aerosol optical depth observations\nused for validation in this paper than the previous two reanalyses and is\nmuch improved and more consistent in time, especially compared to the MACC\nreanalysis. The CAMS reanalysis is a dataset that can be used to compute\nclimatologies, study trends, evaluate models, benchmark other reanalyses or\nserve as boundary conditions for regional models for past periods.