Abstract: The rapid development of civil aviation has increased the demand for higher take-off and landing capabilities at airports. Wake vortices generated during aircraft take-off and landing can impact the safety of trailing aircraft, necessitating a certain safety interval, known as wake vortex separation. Shortening this separation is crucial for improving airport capacity. This paper employs large eddy simulation (LES) and adaptive mesh technology to study the evolution of wake vortices at various altitudes in an unstable atmosphere, taking into account the effects of gusts and stability on vortex dissipation, and finds that vortices dissipate more quickly in strong headwinds and highly unstable atmospheric conditions. Based on this, an LES database for near-ground vortex evolution is established, indexed by wind speed and stability. Existing high-altitude models are tested and extended to include unstable atmospheric conditions, with turbulent kinetic energy incorporated to enhance prediction accuracy. A prediction method for the transition region is proposed, where the evolution of wake vortex circulation can be directly referenced from the near-ground database, while the evolution of wake vortex height requires additional corrections.