内蒙古50余年降水量分布演变特征及趋势

Analysis on Temporal Characteristics and Trend of Precipitation over the Past 50 Years in Inner Mongolia

为研究内蒙古自治区降水量随时间分布演变特征及趋势,利用内蒙古50个测站1960—2011年共52a的年平均降水量,通过线性倾向估计、滑动平均、累积距平、谐波分析、Mann-Kendall法、滑动t检验法等方法,按东、中、西部分区及全区平均,分析了降水量随时间的演变特征及趋势。结果表明：1）52a来内蒙古降水量没有显著的变化趋势。但区域、东中部地区年降水量在1998年前39a为显著上升趋势,之后13a为下降趋势。2）内蒙古全区的降水主要集中在夏季,占全年的60%~70%。降水量从东到西逐渐减少,但季节分配规律相似。3）内蒙古降水量年代际和年际分量都存在减少趋势,区域和东中部共经历了3个比较明显的年代际变化;西部存在15a左右的旱涝交替周期。4）内蒙古区域和东部地区平均降水量突变点在1999年,降水量由增加趋势变为减少趋势。中部和西部变化不显著,没有发生突变。

Annual precipitation data of Inner Mongolia from 46 meteorological stations through 1960 to 2011 were used to analyze the temporal distribution characteristics of precipitation. The trend of the precipitation was analyzed using linear trend calculation, moving average, cumulative anomaly, harmonic analysis, Mann- Kendall method, slide t test. The results showed that： 1） it was no significant for the trend of precipitation in 52 years in Inner Mongolia. Precipitations presented observably increasing trend before 1998, and declined after 13 years in east, central and regional area; 2） precipitation mainly concentrated in the summer, ac- counting for 60~70~//0, precipitation gradually reduced from the east to the west, but followed the similar seasonal distribution rule; 3） interdecadal and interannual precipitations presented the decreasing trend, there were obvious interdecadal changes in eastern, central and regional areas, drought and flood alternative cycle was 15 years or so in the western area; 4） abrupt change year of average precipitation in east and re- gional area in Inner Mongolia was the year of 1999, the trend of precipitation shifted from increase to de- crease, no abrupt change was found and no significant change was observed in the west, there was no abrupt change in the western and central areas.