内蒙古东部夏季降水特征分析

Summer Precipitation Characteristics in the Eastern of Inner Mongolia

利用内蒙古东部48个国家气象观测站1961—2017年逐日降水量资料,对内蒙古东部夏季降水变化特征进行分析。结果表明,57a来内蒙古东部平均夏季降水量增减趋势并不显著,1998年之后降水量处于偏少时期;88%的站点降水减少,其中仅兴安盟高力板和赤峰市翁牛特旗减少趋势显著;夏季降水量空间分布不均匀,特别是呼伦贝尔市降水量等值线受大兴安岭山脉影响呈径向分布;雨季结束日期提前的变化趋势显著,雨季雨量在1998年之后明显减小;降水量历史极值和极端降水阈值呼伦贝尔市西部最小,大值区在通辽市南部、赤峰市东南部;大部分单站超阈值极端降水事件日数较少,仅通辽市东部及赤峰市中部较多;超阈值极端降水事件总日数增减趋势不显著,1998年之前呈显著的增加趋势,1998年之后明显减小。

By using daily precipition data from 48 observation stations in eastern of Inner Mongolia during the period of 1961 to 2016, the characteristics of summer precipitation is analyzed. The results show that over the past 57 years, the average summer precipitation trend in eastern Inner Mongolia was not signifcant but had been less than normal since 1998 obviously. 88 percent of the site’s summer precipitation was reduced, with only the decreasing tendency of Gaoliban in Xing ‘an league and Wengniute in Chifeng were significantly.The spatial distribution of summer precipitation in the eastern of Inner Mongolia was uneven, especially in hulunbuir was decaying from east to west. The end date in east had a signifcant advance trend. And the rainy season precipitation was decreased signifcantly after 1998. The historical extremes of precipitation and extreme precipitation threshold were minimum in the west of Hulunbuir and maximum in the south of Tongliao and the southeast of Chifeng. The superthreshold extreme precipitation days of most sites were less, only in the south of Tongliao and the southeast of Chifeng were more. The change trend of superthreshold extreme precipitation total days was not signifcant but obviously increased before 1998 and then signifcantly reduced.