SCIENTIA GEOGRAPHICA SINICA ›› 2017, Vol. 37 ›› Issue (2): 274-282.doi: 10.13249/j.cnki.sgs.2017.02.014

• Orginal Article • Previous Articles     Next Articles

Spatiotemporal Characteristics of Evapotranspiration Based on MOD16 in the Hanjiang River Basin

Jing Zhang1,2(), Zhiyuan Ren1()   

  1. 1. College of Tourism and Environment, Shaanxi Normal University, Xi'an 710119, Shaanxi,China
    2. School of History and Tourism, Shaanxi University of Technology, Hanzhong 723001, Shaanxi,China
  • Received:2016-03-07 Revised:2016-09-26 Online:2017-02-25 Published:2017-02-25
  • Supported by:
    National Natural Science Foundation of China(41371523);Project of Key Research Base for Humanities and Social Sciences of Ministry of Education(14JJD840004)

Abstract:

Based on MOD16 products from remote sensing and its precision verification, this article analyzed the spatiotemporal characteristics of interannual and annual evapotranspiration and variation characteristics of evapotranspiration under different land cover types from 2000 to 2014, using statistical analysis of GIS, linear trend method and variation coefficient method et al. The results showed as follows: 1) In 2000-2014, the 15-year averaged PET was 1 476 mm and the spatial distribution of PET was decreasing trend from southeast to northwest while the 15-year averaged ET was 654 mm and the spatial distribution of ET in the west and south was higher than in the east and north. The averaged PET and ET are in the opposite order under different land cover types. 2) The interannual variability of PET was 13.63 mm/a and showed a weak increasing trend while ET was -2.3 mm/a and showed a weak decreasing trend. The gap of PET and ET showed an increasing trend, which indicated that water resources in the Hanjiang River Basin was decreasing. Spatial variation trend of PET was “the increasing in the East and the decreasing in the West” while ET was “the decreasing in the East and the increasing in the West”. There was the tendency of drought in the northeast. 3) Interannual PET and ET was a single peak. PET was the largest in June and ET was the largest in July. Both of them were the smallest in December. The maximum gap between PET and ET was the spring drought from April to June. Monthly averages of PET and ET showed a single peak type under different land cover types. The difference of monthly ET for different land cover types was obvious in the vegetation growing season when monthly ET in forestland was the fastest growth rate. 4) Seasonal averages of PET and ET had obvious differences among the four seasons. Spatial distribution of seasonal ET was very significant which greatly attributed to the transpiration of forestland because it was greatest contribution to the annual ET. In 2000-2014, spatial change of seasonal ET was significantly increasing in mountainous western region of the Hanjiang River Basin, while decreasing in eastern region. On the whole, the annual change of seasonal ET was the most obvious in winter, and the weakest in spring.

Key words: evapotranspiration, MOD16, land cover type, the Hanjiang River Basin

CLC Number: 

  • P426.2