Cyclonic activity in high latitudes as simulated by a regional atmospheric climate model: added value and uncertainties

Decadal long simulations of atmospheric circulation in the high latitudes have been carried out using a multiscale atmospheric modeling system that consists of MGO global and regional atmospheric models with respective resolutions of 200, 50 and 25 km in the horizontal. The detailed analysis of extratropical cyclone activity including activity of polar mesocyclones has been conducted for the winter season using an advanced cyclone identification and tracking scheme. To enhance the applicability of high-resolution regional atmospheric modeling in the context of detailed general atmospheric circulation analysis, an end-to-end approach for cyclone trajectory calculation on a unified global and regional grid has been proposed. It has been shown that increasing modeling resolution in the high latitudes allows one to more realistically simulate the activity of baroclinic waves and the thermal regime of the Arctic troposphere. The statistical structure of cyclonic activity has been investigated depending on the spatial resolution of the modeling system and compared with that in the reanalyses and satellite-derived analyses. The performance of the atmospheric models in the simulation of extreme cyclones is evaluated.