2014—2015年度黄河凌情特点分析

Analysis of Ice Flood Characteristics in the Yellow River During 2014-2015

2014—2015年度黄河凌期,黄河干流最大累计封河长度为707 km,较2000年以来均值偏短327 km。分析其凌情特点和主要影响因素,结果显示:流域冷空气势力整体偏弱,致宁蒙河段流凌日期推迟、封冻河段长度短、封冻断面冰层薄;海勃湾水库的运用,致其坝下内蒙古河段封冻长度减少30 km;流凌、封河期宁夏灌区退水和海勃湾水库集中泄流,致封河流量大,封河速度减慢;包头河段低水位首先封河,大量冰凌卡在其上河段,致内蒙古河段水位上高下低,槽蓄水增量上多下少;下游河段流凌和初封期利津站平均流量偏大、水温偏高、平均流速偏大,导致河口地区基本无凌。

During the ice period from year 2014 to 2015, the maximum accumulative length of freeze reached 707 km in the Yellow River mainstream, 327 km shorter than the average length since 2000. The paper analyzed the ice flood characteristics and the main impact factors. The results indicate that a) the weak cold air in the Yellow River basin results in the delay of ice-drift date, the short length of freeze mainstream and the thin ice cover in the Ningxia-Inner Mongolia reach;b) the operation of Haibowan Reservoir leads to 30 km decrease of freeze length downstream of the reservoir in the Inner Mongolia reach;c) the releases from both the irrigation area of Ningxia Province and the Haibowan Reservoir during ice-drift and freeze periods give rise to the discharge increase and the slow freeze rate during freeze period;d) the freeze occurred first in the Baotou reach with low water level, and a plenty of ice was blocked upstream of the river reach, resulting in the high water level and large amount of tank storage in the upstream and low water level and small amount of tank storage in the downstream in the Inner Mongolia reach;e) there was almost no ice in the estuary area, because both the average discharge and water temperature were high in the Lijin Hydrologic Station during ice-drift and early freeze periods in the lower river reach.