FinROSE — middle atmospheric chemistry transport model

In this paper we describe the development and performance of a three-dimensional global middle atmospheric chemistry transport model FinROSE. The FinROSE chemistry transport model includes a numerical scheme for stratospheric chemistry with parameterizations for heterogeneous processing on polar stratospheric clouds (PSC) and on liquid binary aerosols together with a parameterisation of large nitric acid trihydrate particles (i.e. NAT-rocks) and PSC sedimentation. The total number of trace species in the model is 34 and the total number of gas-phase reactions, photodissociation processes and heterogeneous reactions is about 150. The model is forced by external wind and temperature fields. The simulations are normally performed in a 5° x 10° (lat. x long.) grid from the surface up to around 0.1 hPa, with a vertical resolution of ca. 1.5 km in the stratosphere. Long-term simulations (40 to 50 years) have been done using winds and temperatures from ECMWF ERA40 analyses. The performance of the model in describing the stratospheric composition and chemistry is shown and evaluated in this paper. In general, the FinROSE results show a good comparison with measured total ozone. Also the timing, the depth and the deepening of the Antarctic ozone hole, and the responsible processes are captured well in the model simulations.