Tropospheric chemistry in the Integrated Forecasting System of ECMWF

摘要

A representation of atmospheric chemistry has been included in the IntegratedForecasting System (IFS) of the European Centre for Medium-Range WeatherForecasts (ECMWF). The new chemistry modules complement the aerosol modulesof the IFS for atmospheric composition, which is named C-IFS. C-IFS forchemistry supersedes a coupled system in which chemical transport model (CTM)Model for OZone and Related chemical Tracers 3 was two-way coupled to the IFS(IFS-MOZART). This paper contains a description of the new on-lineimplementation, an evaluation with observations and a comparison of theperformance of C-IFS with MOZART and with a re-analysis of atmosphericcomposition produced by IFS-MOZART within the Monitoring AtmosphericComposition and Climate (MACC) project. The chemical mechanism of C-IFS is anextended version of the Carbon Bond 2005 (CB05) chemical mechanism asimplemented in CTM Transport Model 5 (TM5). CB05 describes troposphericchemistry with 54 species and 126 reactions. Wet deposition and lightningnitrogen monoxide (NO) emissions are modelled in C-IFS using the detailedinput of the IFS physics package. A 1 year simulation by C-IFS, MOZART andthe MACC re-analysis is evaluated against ozonesondes, carbon monoxide (CO)aircraft profiles, European surface observations of ozone (O₃), CO,sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) as well assatellite retrievals of CO, tropospheric NO₂ and formaldehyde.Anthropogenic emissions from the MACC/CityZen (MACCity) inventory and biomassburning emissions from the Global Fire Assimilation System (GFAS) data setwere used in the simulations by both C-IFS and MOZART. C-IFS (CB05) showed animproved performance with respect to MOZART for CO, upper troposphericO₃, and wintertime SO₂, and was of a similar accuracy for otherevaluated species. C-IFS (CB05) is about 10 times more computationallyefficient than IFS-MOZART.