| Study on the variation characteristics of reference crop evapotranspiration in recent 40 years in source region of Yellow River |
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| DOI：10.7606/j.issn.1000-7601.2013.06.030 |
| Key Words: reference crop evapotranspiration(ET0) spatial distribution annual and seasonal change variation within the year source region of Yellow River |
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| Abstract: |
| Based on the measured data of 10 meteorological stations from 1971 to 2010 in source region of Yellow River, utilized the Penman-Monteith Formula to calculate the reference crop vapotranspiration(ET0）for each station. Through several methods as mathematical statistic， correlation analysis and wavelet analysis to do the characteristic analysis by s
patial distribution， variation within the year and annual change respectively, for the ET0 values in source region of Yellow River, the results showed that: The ET0 in source region of Yellow River were space uneven distributed, appeared the northwest region more than the southeast region. The monthly variation of showed a typical single peak，also the distribution of ET0 in four seasons appeared big difference. The ET0 in summer was maximum and minimum in winter, secondary in spring and autumn. The ET0 in each season presented a positive correlation with th temperature and sunshine hours, but significent negative correlation with the precipitation and relative humidity. The annual ET0 presented an increasing trend year by year, the yearly ET0 was average increased 6.1 mm·10a-1 in whole source region. During t
he 40 years, the ET0 has appeared two times significent cyclic change as in middle of seventy to metaphase of eighty, almost the cycle was 8 years, but after the 1990, it was basiclly expressed the changing cycle of 5 years. |
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