Which ocean does Lanzhou precipitation come from?

The precipitation in Lanzhou does not come from the ocean. Lanzhou is located in the inland area of China, far from the ocean. Therefore, the precipitation in Lanzhou mainly comes from the water vapor in the atmosphere and the influence of the surrounding mountains. In summer, Lanzhou is often affected by the updraft of the Qinghai-Tibet Plateau, forming a weather phenomenon called "Loess Plateau Vortex". This climate model will bring more precipitation, making Lanzhou often have thunderstorms and short and strong precipitation in summer. In addition, the cold air activity in the northwest may also bring precipitation to Lanzhou in winter, especially when the cold wave is active, there may be snowfall or freezing rain in Lanzhou. Therefore, the precipitation in Lanzhou is mainly influenced by local climate and geographical conditions, not directly from the ocean. Lanzhou is an inland city in China, located on the Loess Plateau in the southeast of Qinghai-Tibet Plateau.