Journal of Geographical Sciences ›› 2010, Vol. 20 ›› Issue (4): 581-598.doi: 10.1007/s11442-010-0581-3

• Climate Change • Previous Articles     Next Articles

Summertime temperature variations in the middle and lower reaches of Yangtze River and their related circulation anomalies in the past five decades

CAI Jiaxi1,2, GUAN Zhaoyong1,2, GAO Qingjiu1,2, LIN Xin3, QIAN Daili1,2   

  1. 1. Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of Information Science &|Technology (NUIST), Nanjing 210044, China;
    2. School of Atmospheric Sciences, NUIST, Nanjing 210044, China;
    3. Fujian Climate Center, Fuzhou 350001, China
  • Received:2009-07-07 Revised:2009-12-06 Online:2010-08-15 Published:2010-08-15
  • Contact: Guan Zhaoyong, Professor; E-mail: guanzy@nuist.edu.cn E-mail:guanzy@nuist.edu.cn
  • About author:Cai Jiaxi (1982–), Ph.D Candidate, specialized in climate dynamics. E-mail: caijx2004y@nuist.edu.cn
  • Supported by:

    The key technology R&D program of China, No.2007BAC29B02; Project of Jiangsu Key Laboratory of Meteorological Disaster, No.KLME060101

Abstract:

Using the daily data of temperature from China Meteorological Administration and the NCEP/NCAR reanalysis from 1960 to 2005, we have analyzed the relationships between the summertime high/low temperature events in the middle and lower reaches of the Yangtze River (MLRYR) and the related circulation anomalies in the Eastern Hemisphere. Our results have demonstrated that a significantly increasing trend is observed in daily minimum temperature in the past 50 years. And in some regions in the Northern Hemisphere, the opposite scenarios are observed in circulation anomalies in lower and upper parts of the troposphere in the years when the temperatures are higher than normal, as compared to those in the years when the temperatures are lower than normal in the middle and lower reaches of the Yangtze River (MLRYR). Additionally, the anomalous circulation structure in vertical direction in both the high and lower temperature years are barotropic. It is found that the emergence and maintenance of the aforementioned anomalous circulations are related to three kinds of wave train teleconnection patterns. Further more, influences of the long wave surface radiation on the air temperature are stronger in the nighttime than that in the daytime. While both the maximum and minimum temperatures have negative relationships with the sensible heat flux but positive relationships with the latent heat flux. To some extent, the anomalous dynamic heating (cooling) caused by the vertical thermal advection as well as the diabatic heating (cooling) caused by diabatic processes can explain the formation of the high (low) temperature events in the middle and lower reaches of the Yangtze River (MLRYR) in boreal summer.

Key words: the middle and lower reaches of the Yangtze River (MLRYR), summertime temperature variations, circulation anomalies