Simulation of the Mediterranean Cyclone ‘IANOS’ using non-hydrostatic Weather Research and Forecasting model: Sensitivity to Convection Parameterizations and Microphysics

Abstract

<p>The Mediterranean Sea’s distinctive and complicated terrain and the surrounding high mountain systems create a favorable environment for cyclogenesis. Despite Mediterranean cyclones being relatively weaker in intensities, smaller sizes, shorter lifetimes, and rarer than mid-latitude cyclones that develop over open oceans, they strongly influence the Mediterranean climate, including extremes. Despite notable improvements in the fine-scale processes, regional models still have considerable uncertainty. They are related to various constraints such as physical parameterization (convection schemes and microphysics), boundary conditions, and horizontal/vertical resolution. This study is focused on the sensitivity to microphysics schemes and convective parametrization using the non-hydrostatic Weather Research and Forecasting (WRF) numerical weather prediction model for a recent intense Medicane, ‘IANOS’, which was formed over the central Mediterranean Sea during 15-21 September. IANOS attained its mature stage on days 17–18 September and landed over the coast of Greece on 18 September. The horizontal grid spacing of 3 km × 3 km and 39 sigma levels up to 25 hPa were taken on one single domain covering most of the Mediterranean Sea, part of Europe, northern Africa, and part of the eastern North Atlantic Ocean. The simulation of IANOS shows strong sensitivity to the initial conditions, and the simulations initialized on 15 September or later show reasonable skill. All the microphysics schemes, ‘with and without’ enabling the convection scheme, reproduce the IANOS characteristics reasonably well with notable inter-simulation differences in magnitude and location. The large discrepancy and inter-simulation difference is noticed in the track and intensity on 18 September before hitting the coast.</p> <p>Keywords: IANOS, WRF, convection parametrization, microphysics</p>