2017年夏季海洋天气评述

2017年夏季（6—8月）大气环流特征为：北半球极涡仍呈单极型位于北极上空，但强度较春季明显减弱。6月，我国近海北部有弱冷空气活动。7—8月，中高纬度槽脊活动进一步减弱，副热带高压西伸北抬，热带气旋活动频繁。我国近海海域主要有15次8级以上大风过程，其中热带气旋大风过程有8次，入海温带气旋过程有5次，强对流导致雷暴大风过程2次。有11次范围较大的2 m以上的大浪过程。仅出现1次范围较大的海雾过程。西北太平洋和南海共生成15个台风，其他各大洋共有热带气旋18个，分别为：大西洋7个、东太平洋11个。海表温度整体呈上升趋势。

Summer 2017 marine weather review

The general atmospheric circulation in summer (June-August) 2017 is characterized by the one center polar vortex, which is still located over the Arctic Ocean, but with much weaker intensity than it was in spring. In June, there are weak cold airs over the northern part of China Sea. From July to August, the trough and ridge are weaker, and the subtropical high pressure belt extends to the west and north. Tropical cyclone activity is frequent. In summer 2017, there are fifteen gale wind processes inshore, among of which, eight gale wind processes are generated by tropical cyclones, five gale wind processes are generated by extratropical cyclones, and two gale wind processes by severe thunderstorms. There are eleven rough wave processes (above two meter) in summer. There is only one sea fog process in summer 2017. There are fifteen typhoons over Western North Pacific and South China Sea. In addition, there are eighteen tropical cyclones (TC): seven TCs over the Atlantic, and eleven TCs over East Pacific. The sea surface temperature (SST) is on the rise in general.