JOURNAL OF NATURAL RESOURCES ›› 2016, Vol. 31 ›› Issue (2): 343-353.doi: 10.11849/zrzyxb.20141350

• Resource Evaluation • Previous Articles     Next Articles

Analysis on the Climatic Characteristics of the Precipitation Variations at “Ya'an Sky-leakage”

ZHOU Qiu-xue1, 2, 3, LI Yue-qing1, JIANG Xing-wen1, ZHANG Jing1, 4   

  1. 1. Institute of Plateau Meteorology, China Meteorological Administration, Chengdu 610072, China;
    2. Sichuan Provincial Meteorological Observatory, Chengdu 610072, China;
    3. Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province, Chengdu 610072, China;
    4. Xinjin Flight College, Civil Aviation Flight University of China, Xinjin 611431, China
  • Received:2014-10-15 Online:2016-02-25 Published:2016-02-25
  • Supported by:
    National Key Basic Research Program of China, No.2012CB417202; National Public Welfare Industry (Meteorological) Special Funds Scientific Research Program of China, No.GYHY201006053 and GYHY201106003; Major Business Program of Southwest Regional Meteorological Center, No.2010-1; Heavy Rain Forecast Innovation Team of Southwest Regional; Major Business Program of Southwest Region, No.2014-3; Science and Technology Research and Development Project of Sichuan Provincial Meteorological Bureau, No.2015-Youth-03

Abstract: Based on the daily precipitation data during 1951-2008 and hourly precipitation data during 1969-2000 at Ya'an station, multiple time scale variations of precipitation amount and precipitation frequency at “Ya'an sky-leakage” which locates at the eastern edge of the Tibetan Plateau are investigated. The result of conventional statistical diagnostic method shows that the annual precipitation and annual rain days are reducing during the last 58 years at “Ya'an sky-leakage”, and the decrease of rain days is more obvious than that of precipitation. Particularly, the annual precipitation sharply declined after the 1990s due to the decreased of both rain days and rainfall intensity. Except in winter, the trends of precipitation in other three seasons are all downward. Among all seasons, the reductions of precipitation and rain days in autumn are the most obvious. The precipitation reduction in flood season accounts for 92.7% of the annual precipitation reduction. The decrease of rain days in flood season is more obvious than that of precipitation, which account for 62.9% of the annual rain days' reduction. After the beginning of the 21st century, the strong precipitation months decreased, and the aggregated period of rain days shortened significantly. The night rainfall is the most prominent characteristic at “Ya'an sky-leakage”. Both the amount and frequency of rainfall in the night are much more than in the daytime. There is a peak of the rainfall in the night, and the increase rate from valley to peak is twice as much as the decrease rate from peak to valley, so it is easy to form heavy rain at night, and it is obviously lasting. However, further analysis found that not only the amount and frequency of night rainfall reduced at “Ya'an sky-leakage”, but also the precipitation peak occurred earlier than before.

CLC Number: 

  • P467