Acta Geographica Sinica ›› 2010, Vol. 65 ›› Issue (9): 1079-1088.doi: 10.11821/xb201009005

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Trends of Estimated and Simulated Actual Evapotranspiration in the Yangtze River Basin

WANG Yanjun1, JIANG Tong2, LIU Bo3   

  1. 1. School of Remote Sensing, Nanjing University of Information Science and Technology, Nanjing 210044, China;
    2. National Climate Center, China Meteorological Administration, Beijing 100081, China;
    3. School of Hydrology and Water Resources, Hohai University, Nanjing 210098, China
  • Received:2010-03-23 Revised:2010-06-10 Online:2010-09-20 Published:2010-09-20
  • Supported by:

    Foundation: National Natural Science Foundation of China, No.40701028; The Basic Research Development Program of China, No.2010CB428401; Foundation of Nanjing University of Information Science and Technology, No.20070134

Abstract:

In this paper, the actual evapotranspiration in the Yangtze River Basin is calculated by the advection-aridity (AA) model with parameters validation during 1961-2007 and simulated by the general circulation model (ECHAM5/MPI-OM) from 1961 to 2000. The linear regression method and nonparametric Mann-Kendall test are used to examine the trends of annual, inter-decadal and seasonal estimated actual evapotranspiration. The results show that the annual actual evapotanspiration estimated by the above two methods presents the same decreasing trends in the upper and the mid-lower reaches of the Yangtze River, and this decrease is more significant in the mid-lower than in the upper Yangtze. The significance of decreasing annual actual evapotranspiration calculated by AA model is higher than that simulated by ECHAM5/MPI-OM, and the decreasing rate is about -9.3 mm/10a and -3.6 mm/ 10a respectively. The former is attributed to the significant decreasing trend in summer actual evapotranspiration, while the latter is caused by a significant decreasing trend in autumn and spring actual evapotranspiration. In the mid-lower Yangtze River, the seasonal actual evapotranspiration estimated by the two methods displays consistent changing trends, i.e. decreasing actual evapotranspiration in spring, summer, autumn, and increasing in winter. In the upper Yangtze River, the seasonal actual evapotranspiration estimated by the two methods shows similar downward trends in spring and autumn; the summer and winter actual evapotranpiration estimated by the two methods shows upward changing trends.

Key words: actual evapotranspiration, AA model, ECHAM5/MPI-OM model, Yangtze River Basin