北太平洋中尺度涡时空特征分析

Spatial-Temporal features of eddies in the North Pacific

利用1993~2011年19 a的AVISO卫星高度计资料研究了北太平洋(10°~60°N,120°E^100°W)中尺度涡的时空分布特征,结果表明:北太平洋每年约产生1 800余个涡旋,其中气旋涡稍多。北太平洋东部沿岸、西北沿岸、黑潮延伸体北侧、副热带逆流区是中尺度涡的高发区,春、冬季是涡旋的高发季节。涡极性分布以35°N为界,北部多反气旋涡,南部多气旋涡。涡旋半径以100 km左右为主,并且基本随纬度升高而减小,涡旋数量随着周期增长而急剧下降。反气旋涡的平均半径和周期均大于气旋涡。利用Argo浮标剖面资料分析的6个个例涡旋的垂直结构显示,每个涡旋都有其独特的冷暖核结构,深度不同。研究结果对于分析北太平洋涡动能分布及传输具有一定的参考价值。

The spatial-temporal features of eddies in the North Pacific （NP） were analyzed based on the AVISO satellite altimetry data obtained during 19 years （1993-2011）. The vertical structure of six eddies was also studied using the Argo floats data. Averagely, about 1810 eddies emerge annually in the NP and the cyclonic eddies are preferred. The eastern coast and northwest of the NP, Kuroshio extension and subtropical area are high incidence areas for eddies. Furthermore, there are more eddies emerging in spring and winter. 35±N can be used as the dividing line on eddy polarity with more cyclonic eddies than anti-cyclonic eddies in the north of it. The eddy scale and lifetime decrease as altitude increases, but the average scale and lifetime of anti-cyclonic eddies are longer than cyclonic eddies. The vertical structure of six eddies shows different warm （cold） cores for structure and depth.