Generating Mechanism and Type of Gust Front and Its Subjective Identification Methods
This paper summarizes the research results about gust fronts in China in recent years, illustrates their spatial structures, types and characteristics, discusses formation mechanisms for narrowband echoes of gust fronts, proposes the subjective recognition methods to gust fronts. The results show that based on the radar data analysis, gust fronts can be divided into two types: The static gust front and the sport gust front of the original thunderstorm, and the former can be divided further into two subtypes. The feedback effect of gust fronts for the original thunderstorm is completely different because of their different types. The formation mechanism for narrowband echoes of gust fronts can be briefed as two categories: The first is Bragg Scattering caused by the pulsation of atmospheric refraction index gradient, and the second is Particle Scattering caused by insects. Using the characteristics of reflectivity factor and radial velocity, we can identify the location and scope of gust fronts and can forecast their extrapolation. Because gust fronts are close to the ground in the lower atmosphere, we should use a lower elevation of radar data to identify them. Using the radar echo characteristics of gust fronts, the formation, development and dissipation can be comprehensively identified, matching up the variation of mesoscale convective clouds and arcus cloud lines of the high resolution satellite visible cloud images and combined with surface mesoscale observation data.