2018年夏季海洋天气评述

2018年夏季（6—8月）大气环流特征为：北半球极涡呈单极型分布，主体位于北冰洋上空，中高纬西风带呈4波型分布。受大尺度环流影响，6—7月，我国南方海域多热带气旋活动，北方海域多海雾；7—8月副热带高压位置较常年偏北，影响华东的台风明显偏多。2018年夏季，共有18个台风命名，比常年平均偏多7个。我国近海夏季的大风、大浪与台风活动关系密切。有20次8级以上大风过程：其中热带气旋过程大风有13次，两次伴随冷空气活动；温带气旋、准静止锋引发大风5次；另外，有2次过程主要由季风引起。有7次比较明显的海雾过程出现，其中6月出现4次，7月3次。发生13次2 m以上的大浪过程，其中，6月3次，7月和8月各5次。其他各大洋共有18个命名热带气旋生成，分别为：大西洋4个、东太平洋14个。

Summer 2018 marine weather review

The main characteristics of the general atmospheric circulation in summer (from June to August) 2018 are as follows. The polar vortex was characterized by a monopole pattern in the Northern Hemisphere, which centered over the Arctic Ocean. The westerlies in middle and high latitudes presented a four-wave mode. Affected by the large-scale circulation, in June and July there were more tropical cyclone activities than perennial average in the southern sea areas of China and more sea fog activities in the northern sea areas of China. In July and August, the subtropical high lay more northward than ordinary yeas, therefore a remarkable number of typhoons hit East China. There were 18 typhoons nominated over western North Pacific and the South China Sea in this summer, which was 7 more than the previous average. Tropical cyclone activities are closely related with summer gale events and big waves in offshore areas of China. There were 20 gale events stronger than 8 grade this summer, including 13 produced by tropical cyclones (two processes accompanied with cold air activities), 5 by extratropical cyclones and quasi-stationary fronts, and two mainly by monsoon. There were 7 massive sea fog events over offshore areas in this summer, including 4 in June and three in July. Thirteen rough sea wave events above two meters occurred, including three in June, 5 in July, and 5 in August. There were 18 tropical cyclones over global oceans except western North Pacific, including 4 over the North Atlantic and 14 over the East Pacific.