The influence of merging and individual storm splitting on mesoscale convective system formation

Abstract

The aim of present study is to simulate the formation of mesoscale convective system (MCS) through splitting and merging of two single convective storms that is characteristic for mountainous regions by help of cloud-resolving mesoscale model. Features of simulated storms are as follows: they are aligned along leading flow at different stages of life cycle under sharp-sheared condition. The storm in upwind direction (denoted as primary) is initialized earlier as it is a common feature in reality. Formation of MCS passes by several phases as follows: - Primary storm moves faster along leading flow direction than secondary one that is initialized later. Both storms split into right- and left-moving storms in such a manner that primary storm splits at first; - Boundaries of cold air outflows associated by single storms collide. At their intersection air is forced lifted upward, possibly forming a new convection; - As a result the merging process produces the MCS in which the single storms are distributed along curved line. Above results encourage modelers to use more frequently the cloud-resolving models in simulations of great variety of MCS.