新疆额尔齐斯河南湾水文站开河规律探讨及武开河成因分析

1997年3月29日额尔齐斯河南湾水文站发生了有记录资料（1985年12月至今）以来唯一一次特殊“武开河”解冻冰情现象，冰情极其特殊且影响后果严重，有必要全面分析其特殊冰情现象、特征及其影响因素。利用“1997·3·29”推冰前后的实测冰情、气温、水位等资料，对特殊“武开河”推冰现象、特征及其主要影响因素进行分析，结果显示：相较于其他年份解冻期气温缓慢稳定上升，这次“武开河”推冰现象发生前气温偏低；受气温转正时间短，气温偏低和冰厚较厚因素制约，“武开河”冰情发生前整个河流断面无推冰迹象，岸边无融冰，只有冰上流水现象；上游开河略早，来水量增加迅猛。“武开河”发生与最大冰厚间无必然因果关系，但上游来水量的急剧增加，水位快速上涨对于“武开河”解冻冰情现象的发生起了决定性作用。新疆阿勒泰地区发生冰凌溃坝型洪水的风险较低，对冰凌灾害的研究与预防方面应主要加强对推冰现象及过程的研究与预警方面。

Discussion on the River Break Law and Mechanical Break-Up of Nan Wan station at Irtysh River in Xinjiang

The only mechanical break-up event of river ice cover in lrtysh River occurred on March 29,1997 in historial recorded data since December 1985.The river ice conditions of mechanical break-up event is incredibly special,and its effect is serious.Hence,it is necessary to comprehensively analyze its phenomenon,character istics and influencing factors of this break event of river ice.Based on the observed data sets of river ice conditions,air temperatures,and water levels before and after the March 29,1997,this paper analyzed the phenomenon,character istics and main influencing factors of the mechanical break-up event of river ice cover.The rapid temperaturerising might have been the main meteorological control factor for the event.Compared with the steady rise of the temperature during the breakup period in other years,the air temperature was relativeely low before March 29 and there was no melting ice along the bank,only the phenomenon of running water on river ice.With the rapid rise of temperature,large amounts of upstream river ice breakup led to mechanical break-up event of river ice cover.Although the risk of ice jam flooding in the lrtysh River Basin is low,the ice jam and snowmelt flood and its cascade disasters caused by rapidly warming events in spring and winter should be prevented.