ИСТИНА

Mesocyclones in high latitudes are important maritime atmospheric phenomena, characterized by strong wind speeds and surface heat fluxes. The lack of assimilated observational data in Southern Hemisphere in the global ocean and atmospheric models and also the rough resolution of the latter does not allow realistic representation of mesocyclones in these datasets. Most of modern studies of the mesocyclone activity in Southern Hemisphere are using tracking algorithms based on reanalyses data, significantly underestimating number of mesocyclones and their intensity (Irving et al., 2010; Pezza et al., 2015). Thus, dynamical characterization of mesocyclones, developed in these studies covers only a fraction of mesocyclone population. In this study, we present thermodynamical and lifecycle characteristics of polar mesocyclones in SH, basing on the high-resolution (10 km) Weather Research and Forecasting model regional hindcast for winter 2004. The model configuration is chosen using the previous experience of mesoscale modelling in polar regions (such as ASR, AMPS) and additionally includes SST assimilation from OSTIA reanalysis and spectral nudging for synoptic scale phenomena (>1000 km). The hindcast is validated involving the following observational data: satellite-derived integral water vapor and cloud liquid water content (AMSR-E), QuikSCAT surface winds, AMRC Antarctic Automated Weather Station Program weather stations data. The WRF reproduced 95% of polar mesocyclones of satellite-based dataset of the Southern Ocean mesocyclone tracks (Verezemskaya et al., 2017). Dynamical characteristics of polar mesocycones from satellite database such as surface fluxes, CAPE/CIN, existence of cold/warm core, Eady rate, potential vorticity anomalies are calculated for different types of mesocyclones according to their cloudiness pattern type and large-scale background conditions. For each parameter, we built composite mesocyclone and statistics of its distribution over all mesocyclones of this type. Mesocyclones’ clustering is investigated in the dynamical characteristics space.