Acta Geographica Sinica ›› 2018, Vol. 73 ›› Issue (11): 2086-2104.doi: 10.11821/dlxb201811004

• Climate Change and Earth Surface Processes • Previous Articles     Next Articles

Effects of urbanization on spatio-temporal distribution of precipitations in Beijing and its related causes

ZHU Xiudi1,2,3(),ZHANG Qiang1,2,3(),SUN Peng4   

  1. 1. Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing Normal University, Beijing 100875, China
    2. Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China
    3. Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
    4. College of Territorial Resources and Tourism, Anhui Normal University, Wuhu 241002, Anhui, China
  • Received:2017-10-31 Online:2018-11-25 Published:2018-11-22
  • Supported by:
    Creative Research Groups of National Natural Science Foundation of China, No.41621061; National Science Foundation for Distinguished Young Scholars of China, No.51425903; National Natural Science Foundation of China, No.41771536, No.41601023

Abstract:

Due to rapid urbanization and relevant impacts on precipitation in both space and time, effects of urbanization processes on precipitation changes have been widely discussed in recent years. Based on hourly precipitation dataset from 20 stations covering the period of 2011-2015 across Beijing city, statistical methods such as circular statistical method were applied to examine spatio-temporal characteristics of precipitation with respect to precipitation types, extreme precipitation events and so on. The results indicated that: (1) regions in the central Beijing city are dominated by higher rainstorm precipitation amount, duration and precipitation intensity. Compared with rainstorm events in suburbs, precipitation processes in the central city are characterized by long duration and larger precipitation amount. Urban Rain Island effects could contribute to the above-mentioned rainstorm changes in the central city. (2) Uneven daily distribution of precipitation can be found across Beijing with remarkable regional difference. Rainstorm events mostly occurred after noon, accounting for 47.53% of the total precipitation type. Rainstorms in mountainous regions, northern and southern Beijing occurred mostly after noon, at noon and even at night. However, due to valley wind circulation and heat island circulation, precipitation patterns in central Beijing are relatively complicated and storms in western-central part of the city occurred mainly at nighttime. (3) Peak value of precipitation intensity of rainstorms occurred mainly during 12:00-19:00 and delayed occurrence of peak rainstorm values was observed in central city when compared to that in suburbs. Meanwhile, altitude can further induce uncertainty in occurrence time of peak precipitation amount. (4) The extreme precipitation index and the continuous drought as well as moisture index showed the high value in the urban area. The high value of the frequency of extreme precipitation index was found in the downwind direction of the urban area. Urbanization may indirectly increase the risk of extreme precipitation by population growth and land-use change.

Key words: urbanization, precipitation process, spatio-temporal distribution, extreme precipittion, rain type, circular statistical method