DEVELOPMENT OF THE ARID CLIMATE OF NORTHW ESTERN CHINA

The arid climate of Northwestern China has three developmental stages with different, geneses. The area was hot and arid during the Cretaceo us-Eocene due to its location on the subtropic high-pressure belt cont rolled by the planetary wind system. It was warm and arid during the N eocene, because the temperature had dropped after the Eocene and the p aleo-monsoon was very weak, affecting only the coastal areas in China. In the Neocene this area was influenced by the modified Westerlies co ming far from the Atlantic Ocean. In the Quaternary, it was cold and a rid during the ice ages or temperate and arid in the interglacial peri ods and the Postglacial.