Resources Science ›› 2017, Vol. 39 ›› Issue (5): 964-977.doi: 10.18402/resci.2017.05.16

• Orginal Article • Previous Articles     Next Articles

Spatio-temporal distribution characteristics of potential evapotranspiration and impact factors in China from 1961 to 2015

Xia WU(), Peijuan WANG(), Zhiguo HUO, Yueming BAI   

  1. Chinese Academy of Meteorological Sciences,Beijing 100081,China
  • Received:2017-01-03 Revised:2017-03-15 Online:2017-05-20 Published:2017-05-20

Abstract:

The spatio-temporal distribution characteristics of ETo regarding national and four climatic regional scales were analyzed at annual,seasonal and decadal scales to obtain the spatio-temporal pattern for ETo. Results show that the average annual ETo is 620-1729mm in China. The regions with the highest ETo are mainly distributed in arid regions,while areas with lower ETo are concentrates in semi-arid,humid and semi-humid regions at both 55-year average and different decadal scales. At a seasonal scale,the spatial distributions of ETo show a clear pattern:ETo is the highest in summer,followed by spring and autumn,and the lowest in winter,accounting for 39%,30%,21% and 10% of average annual ETo respectively. Temporally,the average annual ETo decreased at a rate of 0.52mm/a from 1961 to 2015,and the decreasing trend has a mutation phenomenon in 1972. Although there is an increasing trend since the last decade of the 20th century,it did not detect the mutation year using Mann-Kendall methods. Trends of ETo in different climate regions are distinctive. ETo in most sites decreased in arid region and humid regions,and the meteorological stations tended to decrease in arid regions more than in humid regions. In semi-arid and semi-humid regions,the number of sites is roughly equivalent regarding those that increased or decreased for ETo. More than 85% of the sites in our country have ETo mainly affected by wind speed and sunshine time. The decreasing trend of ETo in recent 55 years was mainly caused by a decrease in wind speed,reduced sunshine time and a slight increase in vapor pressure. The major reason of ETo increase was vapor pressure, and the second were sunshine time and the lowest air temperature.

Key words: potential evapotranspiration, wet and dry climatic regions, spatio-temporal distribution characteristics, reason for change, China