Why are the cloud maps of Ulaanbaatar always round?

The cloud image of Ulaanbaatar is always round and related to radar failure. There is a big circle in the satellite cloud image, which is related to radar failure. Satellite cloud image, a top-down image of cloud cover and surface features on the Earth observed by meteorological satellites. The cloud images received mainly include infrared cloud images, visible light cloud images and water vapor images. Satellite cloud images can be used to identify different weather systems, determine their locations, estimate their intensity and development trends, and provide a basis for weather analysis and weather forecasting. In areas such as oceans, deserts, and plateaus that lack meteorological observation stations, the data provided by satellite cloud images make up for the lack of conventional detection data and play an important role in improving forecast accuracy.