一、引言 渤海及黄海北部处在中纬度地带,每年冬季都有不同程度的结冰现象。以辽东湾结冰时间最长,全部结冰日数平均为100多天,约占全年的三分之一。从全海区看,建国后冰情较重的有1957、1968、1969、1977年的1、2月份,尤其是1969年,渤海海面发生了该海区历史上罕见的冰封,整个海面几乎全部被海冰所覆盖,严重阻碍了海上的航运交通 I. INTRODUCTION The Bohai Sea and northern Yellow Sea are located in the mid-latitudes. There are different degrees of icing each winter. Liaodong Bay to freeze the longest time, the average number of days all frozen more than 100 days, accounting for about one-third of the year. Judging from the whole sea area, after the founding of the PRC, the heavier ice conditions were 1957, 1968 and 1969 respectively. In January and February of 1977, especially in 1969, rare sea ice in the history of the sea occurred in the Bohai Sea. Almost all of the sea surface was covered Sea ice coverage, a serious impediment to maritime shipping traffic