CONICET | Buscador de Institutos y Recursos Humanos

A multicellular storm (Torres Brizuela and Nicolini, 2006) developed over the area of Resistencia (27°27S, 59°03W), Province of Chaco, Argentina during the morning of 19 October 2000. A previous paper concluded that this storm had strong evidences of the typical conditions leading to bow-echo development and the numerical simulations performed in this study also evidenced the genesis of this system in the area. The satellite images of this system displayed the evolution with a pattern and time length similar to the expected for bow-echoes. A descending rear-inflow jet (RIJ) is frequently responsible for observed wind damage swaths preferably poleward of the bow apex. This convective structure more frequently evolves within an environment associated with elevated moisture (surface dew-point greater than 20C),moderate to strong CAPE values and with a moderate to strong vertical wind-shear in the lowest 2.5km AGL.The aim of this work is to study the role of the Coriolis force on the evolution structure of a bow echo produced over northeastern Argentina. Two different numerical experiments have been performed aimed to understand the role of the Coriolis force in organizing the convective structure of this particular event. The first one (E1) was run without Coriolis force, a second one with the Coriolis force included (E2). Numerical simulations of the 19 October 2000 convection using ARPS reproduced correctly the significant features and arrangement of a bow-echo structure. This bow convective line comes up more clearly in the E2 experiment. In terms of vertical vorticity, related with descending motion the southern apex of the system becomes dominant for both experiments. The rotation in this apex is defined in a smaller area for E2 experiment. In terms of a stronger magnitude of the RIJ, E1 reproduces it better, but in terms of characteristical lenghts of a typical bow-echo E2 shows a better representation. A remarkable pattern of E2 simulation is that mesovortices are insinuated, result already found by different authors.