Chinese Journal of Agrometeorology ›› 2015, Vol. 36 ›› Issue (06): 692-698.doi: 10.3969/j.issn.1000-6362.2015.06.005

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Temporal and Spatial Variation of Reference Crop Evapotranspiration and Contribution of Main Factors in the Middle Area of Shandong Province

HUAN Hai-jun,YANG Zai-qiang, LIU Yan, XIA Fu-hua   

  1. 1.Zibo Meteorological Bureau of Shandong Province, Zibo 255048, China;2.Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing 210044
  • Received:2015-03-30 Online:2015-12-20 Published:2015-12-17

Abstract: Based on the meteorological data in the middle areas of Shandong Province from 1980 to 2014, the reference crop evapotranspiration(ET0) was calculated by Penman-Monteith model, the spatial and temporal distribution characteristics of the main meteorological factors and ET0 of different time scales were analyzed, and the contribution to ET0 changes of different time scales made by main meteorological factors was also discussed with a method based on sensitivity coefficient. The results showed that annual average ET0 of the plain was 1165.8mm, and the mountainous area was 1144 6mm in the past 35 years,which had an extremely significant reduction trend in the plain, at the rate of 22.2mm·10y-1(P<0.01).The seasonal average ET0 from high to low was summer, spring, autumn and winter, which had an increasing trend in spring and a reduction trend in other seasons. The maximum monthly average ET0 appeared at June, the minimum value appeared at January, and annual distribution presented parabolic shape.The main space distribution of all time scales was basic synchronization. Annual and seasonal average ET0 was sensitive to the changes of relative humidity and it tended to increase. The sensitivity of monthly average ET0 to main meteorological factors had different changing rules by the month. The most sensitive factor which affected monthly average ET0 was relative humidity from March to June, September and October, wind speed in January, February, November and December, percentage of sunshine in July and August. According to the main contribution rate, wind speed had the largest contribution to the annual average ET0, seasonal and monthly average ET0 was different between main contribution factors while the main contribution factors at the time scale in plain and mountain was basically the same. The total contribution rate of four main meteorological factors could basically explain the reasons of ET0 changing of different scales.

Key words: The middle area of Shandong Province, Reference crop evapotranspiration, Relative changing rate, Sensitive coefficient, Contribution rate