近56年来内蒙古东胜矿区潜在蒸散发的时程变化

Temporal Changes of Potential Evapotranspiration in Dongsheng Mining Area in Inner Mongolia During Recent 56 Years

采用Penman-Monteith公式计算潜在蒸散发量（ET0）,研究东胜矿区1957-2012年潜在蒸散发量的演变趋势,并就其时间变化序列进行频率分析和小波分析。结果表明：该区ET0年均值为1 128.1mm,线性变化趋势为0.9mm/（10年）,经Mann-Kendall检验增加趋势不明显,但2003年可认为是突变点。ET0的多年月均值为94.0mm,12月份最小,5月份最大。ET0存在明显的季节变化特征,冬季最小,春秋次之,夏季最大;频率分析得出该区56年来的最大值（1 284.9mm）属于300年一遇,而50年一遇的ET0为1 243.2mm,10年一遇的ET0为1 197.1mm;小波分析发现,该区ET0在25~30年较大尺度上的周期最明显,经历了7个升高-降低的循环交替,震荡主周期为28年,平均周期为11.5年左右。

Based on the daily meteorological data of Dongsheng station in Inner Mongolia from 1957 to 2012, the potential evapotranspiration（ET0 ） was calculated using the Penman-Monteith Method which was recommended by FAO and the trend of ET0 was also investigated. Moreover, the frequency analysis and wavelet analysis of the time series variation of ET0 was conducted. The results showed that： （1）The mean annual ET0 in the mining area was 1 128.1 mm and the linear changing trend of ET0 was 0.9 mm/（10 a）. The increasing trend was not apparent from the Mann-Kendall test. However the year 2003 could be considered as an abrupt point. The monthly mean ET0 was 94.0 mm. The value in May was maximum and in December as minimum. ET0 had a distinct seasonal variation, in which winter ET0 was maximum, spring and autumn ones occupy the second place, and summer ET0 was minimum. （2）The frequency-analysis showed that the largest ET0 of this area during latest 56 years was 1 284.9 mm, which was 300 years frequency. Besides, ET0 on a 50-year cycle and a 10-year-cycle in this area were 1 243.2 mm and 1 197.1 mm respectively. （3）The wavelet analysis indicated that there were obvious periodic oscillation of 25-30 year for the annual ET0, which experienced 7 rising-dropping alternation circulation. The dominant period of ET0 oscillation was 28 years and the average period was about 11.5 years.