短生命周期海洋涡旋的时空分布特征

中尺度涡旋在海洋中分布广泛,是海洋动力、营养物质等混合和输运的重要途径。统计发现海洋中超过80%的涡旋生命周期不超过1个月,属于本文定义的短生命周期涡旋。本研究采用统计、对比等方法,对全球尺度,较短生命周期涡旋的时空分布特征进行了分析。研究表明,短生命周期涡旋与大洋中环流系统密切相关,其最易发生在暖流和寒流的交汇处以及运动方向相反的两种环流的交汇处,且在除30°S～30°N的热带地区外均表现为气旋式略多于反气旋式。低纬地区,短生命周期涡旋在每年的冷季数量较多,而高纬地区与之相反。除存在大规模东向环流的海域,短生命周期涡旋一般向西迁移,同时气旋式涡旋略倾向于赤道偏转,反气旋式略倾向于极地偏转。短生命周期涡旋的平均位移和平均迁移速率呈相似的赤道对称分布规律。

Temporal and spatial properties of short-life oceanic eddies

Mesoscale eddies are widely distributed in the ocean and play a significant role in the mixing and transporting of momentum and nutrients. Statistics suggest that more than 80% eddies'' lifetime are less than 1 month, belonging to the defined "short-life eddies" in this paper. This design adopt statistics and comparison, commit to having a earlier reasearch of global scale, short-life eddies. Results show that short-life eddies have a close correlation with ocean current. The most productive places for short-life eddies are those where warm and cold currents or two currents with opposite directions meet, and except in tropical areas of 30°S-30°N, the short-life eddies in other areas have a slight preference for cyclonic. Seasons with low temperature are favorable for short-life eddies in low latitudes, while seasons with high temperature are favorable in high latitudes. Short-life eddies tend to propagate westward in most of areas, however, they notable propagate eastward in eastward currents areas. Meridional deflection is quite messy, but with a tiny preference for equatorward and poleward deflections of cyclones and anticyclones, respectively. The distribution of average displacement and propagation velocity have similar regulation.