黄河宁夏段凌汛期气温变化特征

利用宁夏1991~2010年20 a凌汛期水文和气温序列资料,研究了宁夏凌汛期特征、凌汛灾害发生主要时段,黄河封河、开河集中期与日平均气温之间的关系。结果表明:宁夏凌汛特征为封开河时序相反,小流量、高水位行洪,受强冷空气影响较大;凌汛灾害主要发生在封河和开河期间;日平均气温正负转化日期与封、开河期有对应关系,宁夏封河集中期在12月20日至1月19日;开河集中日期在2月13~20日。在凌汛关键期结合MODIS遥感数据对凌汛灾害监测防范有一定指导意义。

Analysis of Characteristics of Temperature Change in the Ice Flooding Season in Ningxia Section of the Yellow River

Based on the hydrological data and temperature series in the ice flooding seasons from 1991 to 2010,the variation of daily temperature in ice flooding seasons,the main occurring period of ice flooding disaster,and the relationship between the freezing-up/breaking-up periods of the Yellow River in Ningxia section and daily mean temperature were studied.The results show that time se-quence of the freezing-up and the breaking-up of the river was reversed.When a ice flooding occurred,the flow of the Yellow River in Ningxia was small and the water level was high.The ice flooding was affected by the strong cold air.Ice flooding disasters occurred mainly during the periods of freezing-up and breaking-up of the river.The date when daily mean temperature transfered from positive to negative or negative to positive was corresponding to the periods of freezing-up and breaking-up of the river.The concentrated date was from December 20 to January 19 for freezing-up,and for breaking-up,it was from February 13 to 20.Using MODIS remote sensing data to monitor and prevent ice flooding disaster had some guiding significance in the critical period of ice flooding.