2021—2022年度黄河宁蒙河段凌情特性分析

Analysis on characteristics of ice conditions in Ningxia-Inner Mongolia Reach of the Yellow River from 2021 to 2022

2021—2022年度凌汛期,黄河宁蒙河段凌情形势总体平稳,主要呈现出流凌期持续时间长、首封日期偏晚、封河流量偏大、封河长度偏短、槽蓄水增量偏少、开河时间偏早、开河凌峰较小等特点。从热力因素、水流动力因素、河道边界条件和水利工程调度4个方面分析了形成上述特点的主要原因。结果表明,气温整体较常年偏高,且偏高程度呈西高东低分布,是造成流凌期持续时间长、首封日期偏晚、封河长度偏短、开河时间偏早的主要原因;较大的封河流量和河道条件的持续改善,使凌汛期河道过流能力增强,在一定程度上抑制了槽蓄水增量的增加,造成槽蓄水增量偏少;科学合理的水利工程调度,为平稳封河、开河创造了有利条件,是做好防凌工作的重要措施。

During the ice-flood season from 2021 to 2022,the ice conditions in Ningxia and Inner Mongolia reach of the Yellow River is generally stable,mainly characterized as follows:long duration of ice-run,late appearance of the first freezing-up date,large discharge of freezing-up,short length of freezing-up,small increment water storage,early break-up date and small ice flood peak.The main influencing factors of the above characteristics are analyzed from four aspects:thermaland hydrodynamicfactors,river boundary conditions and water regulation.The results show that:the main reason for long duration of ice-run,late appearance of the first freezing-up date,short length of freezing-up and early break-up date is that the overall temperature is higher than normal,and the distribution higher in the west and lower in the east;large discharge of freezing-up and continuous improvement of river channel conditions have enhanced the flow capacity during the ice flood season,which inhibited the increase of increment water storage in river channel to a certain extent,resulting in less increment water storage in river channel;the scientific and reasonable regulation of water projects has created favorable conditions for the steady freezingup and break-up,which is an important measure in ice prevention.