Mesoscale processes associated to deep moist convection in central Argentina

RUIZ JUAN JOSÉ; SALIO PAOLA; ALVAREZ IMAZ MARÍA DE LOS MILAGROS; SCHNEIDER JULIAN

Tarquinia

Workshop; Third International Training School on Convective and Volcanic clouds detection, monitoring and modeling; 2016

The continental region to the east of the Andes that is includes North and center of Argentina, South Brazil, Paraguay and Uruguay (SESA) is well known for deep convection where many mesoscale processes are involved. Whereas large scale processes set the favorable environment for the development of deep moist convection, mesoscale processes affects in the initiation of the storm and its evolution. The characteristics of the topography on the central area of Argentina, mainly associated with the Sierras de Córdoba, show a strong initiating convection zone in the afternoon for systems which can acquire extreme characteristics. There are still large uncertainties in the interaction of the processes of initiation and growth of convection in this region strongly influenced by high impact events (hail, gusts, tornadoes). Also there is a strong gradient of vegetation type which indicates that existence of different concentration of soil moisture in a small area. Simulations were performed with the WRF model considering an event of deep moist convection that occurred at 15Z on January 22, 2014 to the east of Sierras de Córdoba. In order to study the processes involved in the initiation of convection for this case, 5 simulations coupled with the control simulation are performed. In the experiments, the topography is modified and changes are also made regarding soil moisture. To change the height of the Sierras de Córdoba, smoothing the height thereof is done with and without retaining the fluctuations of the field and changes in soil moisture. Thus, the 5 simulations are a product of various combinations of modifications to the ground. To study the results of the 5 experiments, several charts of variables associated primarily mesoscale movements are made in order to compare and see whether the presence of topography and/or the soil moisture are relevant for starting convection for this situation. From the graphs made, it attempts to analyze the evolution of the planetary boundary layer to determine the influence of the fluxes of sensible and latent heat in the formation of mesoscale circulations and understand the impact of these circulations at the beginning of the convection.