Abstract:
Although previous studies have analyzed the unique structural characteristics of the polar vortices on Earth, Venus, Mars, and Titan, the understanding of the polar vortices on Venus and Titan is primarily based on small-scale case studies due to the limited resolution and coverage of observational data. Conducting a detailed comparison of the polar vortex characteristics between the major terrestrial planets and Titan in the solar system is more challenging. In order to more finely compare the polar vortex characteristics of the main terrestrial planets in the solar system with Titan, we have achieved the optimal estimation of the polar vortices of Venus and Titan under existing conditions based on the advanced VCD2.3 and TitanWRF model. At the same time, combining ERA5 and EMARS databases, a detailed spatiotemporal comparison of polar vortex characteristics between terrestrial planets with atmospheres in the solar system and the most Earth-like Titan satellite was conducted for the first time. Here, we demonstrate that: (1) The circulation characteristics of Mars above the 1 mbar level are very similar to those at
1000 mbar in the lower layers of Titan, with seasonal variations of the same height. (2) In contrast to the vortex structure that is stably maintained in the lead direction in the polar regions of Mars and Earth during the winter, the time of occurrence of the peak vortex intensity at Titan and Venus is gradually shifted forward with increasing altitude. (3) When Venus undergoes vortex instability drift, the polar vortex at an altitude of 1 mbar breaks up into banded structures, a phenomenon that closely resembles the twisting deformation of PV structures during weak stratospheric polar vortex events on Earth.