The north edge of this region is the remarkable transition of the climate from middle subtropics to north subtropics and topography from the west plateau land to the east plain and hilly land.

• 其北部边缘区处于我国中部地区，气候由中亚热带向北亚热带过渡，地貌由西部高山高原向东部丘陵平原过渡。