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基于黄河上游38个站点近50年的资料,分析了降水、气温的时空变化特征,采用线性回归法和非参数Mann-Kendall方法,检验了兰州上游各子区间降水和典型站点气温的变化趋势。结果表明:1)20世纪90年代以来,兰州以上各区间降水量均少于多年均值,呈现出减少趋势,其中洮河流域最显著,其平均递减率为19.9mm/10a;2)各代表站年均气温呈显著上升趋势,平均升幅在0.09~0.374℃/10a之间;3)就季节而言,冬季升温最明显,其次为秋季,其平均递升率分别为0.199~0.763℃/10a和0.067~0.338℃/10a。
Based on the data of 38 stations in the upper reaches of the Yellow River for nearly 50 years, the temporal and spatial variations of precipitation and temperature were analyzed. The linear regression method and non-parametric Mann-Kendall method were used to test the trend of precipitation and temperature at each sub-interval in the upper reaches of Lanzhou. The results show that: 1) Precipitation in each interval above Lanzhou is less than the annual average since the 1990s, showing a decreasing trend, of which the most significant is in the Bahe River basin, with an average decreasing rate of 19.9mm / 10a; 2) The average annual temperature showed a significant upward trend, with an average increase of 0.09 ~ 0.374 ℃ / 10a. 3) In terms of seasons, the temperature was the most obvious in winter, followed by the autumn with the average rate of increase of 0.199 ~ 0.763 ℃ / 10a and 0.067 ~ 0.338 ° C / 10a.