摘要
基于黄河内蒙古段1961—2009年气象与水文观测资料,选取黄河内蒙古段上游磴口站和下游托克托县作为研究对象,利用数理统计等方法,分析凌汛最危险地段上下游气候变化与凌汛期的关系。得出:①黄河内蒙古段的凌汛灾害是黄河上游的河道气温比下段高以及地形比降小等,形成黄河内蒙古段下游先封河、上游先开河的局面,导致磴口到托克托县段成为凌险最严重的地段。②随着气候变暖,近50a黄河内蒙古段开河期提早、封河期推后,凌汛期缩短。尤其在1987年气温发生突变之后,开河期提早和推后趋势更为明显。同时气温突变之后,凌汛期平均温度变异系数增大,封、开河期冷暖变化剧烈,致使封开河期的波动性增大。③影响黄河内蒙古河段开、封河的关键因素是日平均气温小于-5℃的积温、日平均气温小于-5℃持续时间和封、开河期温度以及封、开河期流量大小等。极端温度事件如寒冷日数、冷夜指数和冷日指数的减少,以及暖夜指数和暖日指数的显著增加也是影响黄河内蒙古段凌汛期缩短的原因之一。
Based on meteorological and hydrological data observed at Inner Mongolia section of Yellow River during 1961-2009,we selected the DengKou and TuoKe Tuo stations,which are located in the upstream and downstream of the Inner Mongolia section respectively,to study the relationship between climate change and ice slush period using mathematical statistics method.Results are drawn as follows：（1） The air temperature in upstream is higher than that in downstream and the terrain gradient is small at Inner Mongolia section of the Yellow River,which lead to break-up in the upstream while freeze-up in downstream of the Inner Mongolia section.So ice slush motion is the most serious in this section.（2） Along with the climate warming,the break-up date of the Yellow River become early and freeze-up date become late,thereupon the ice slush period became short over the past 50 years.Especially after temperature occurring mutation in 1987,these changes became more obvious.Meanwhile the average temperature variation coefficient increases and temperature has dramatic change during the freeze-up period through the break-up period,which leads to acute fluctuation of ice slush period.（3） The key elements influencing the ice slush period at Inner Mongolia section of the Yellow River include-5 ℃ accumulative temperature,-5 ℃ lasting duration,air temperature and river runoff during the ice slush period,etc.Besides,the extreme temperature factors such as decrease of the number of coldness days,cold night index and cold day index,and increase of the warm night index and warm day index are also the reasons of the ice slush period shortening at Inner Mongolia section of Yellow River.
出处
《中国沙漠》
CSCD
北大核心
2012年第6期1751-1756,共6页
Journal of Desert Research
基金
国家自然科学基金项目(40765001)
国家科技支撑计划项目(2007BAC29B04)共同资助
关键词
凌汛期
变化趋势
气候变化
黄河内蒙古段
ice slush period
variation trend
climate change
Yellow River
Inner Mongolia section
