A review of research on boundary convergence lines triggering of deep and moist convection

Boundary layer convergence lines (BLCLs), an important type of weather system that can trigger deep moist convection, correspond to quasi-linearly extending airflow confluence zones in the boundary layer. Multiple types of BLCLs exist, and mechanisms for their triggering of convection are complicated. This paper summarizes the existing studies on the climatological statistics of BLCLs (excluding cold fronts) and mechanisms for their triggering of convection, and the effects of local temperature and moisture disturbances on the convection triggering. These studies have presented that the triggering probability, the storm location and time correlation are all affected by different synoptic systems and BLCL types in different regions. Under certain favorable conditions, local temperature and moisture can not only affect BLCL intensity, but also affect the distribution of atmospheric stratification near BLCLs, and thus convection initiation can occur. Moreover, the dynamical and thermal interactions between local temperature and moisture disturbances and the environment make the convection triggering mechanisms more complicated. The paper also discusses some convection triggering issues that need to be further studied. Based on fine observations and numerical simulation, it is also suggested to carry out more systematic studies on the characteristics and mechanisms of convection triggering for different regions and different types of BLCLs in the future.