| CUI Wei,YANG Jungang,MA Yi. 2016. A statistical analysis of mesoscale eddies in the Bay of Bengal from 22-year altimetry data. Acta Oceanologica Sinica, 35(11):16－27 |
| A statistical analysis of mesoscale eddies in the Bay of Bengal from 22-year altimetry data |
| 基于22年高度计数据的孟加拉湾中尺度涡分析研究 |
| Received:October 08, 2015 Revised:December 31, 2015 |
| DOI：10.1007/s13131-016-0945-3 |
| Key words:mesoscale eddy altimetry data Bay of Bengal eddy characteristics seasonal variability interannual variability |
| 中文关键词: 中尺度涡 高度计 孟加拉湾 涡旋属性 季节变化 年际变化 |
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| Abstract: |
| Eddy properties in the Bay of Bengal are studied from 22 a archiving, validation and interpretation of satellite oceanographic (AVISO) data using a sea level anomaly (SLA)-based eddy identification. A geographical distribution and an eddy polarity, an eddy lifetime and propagation distances, eddy origins and terminations, eddy propagation directions and trajectories, eddy kinetic properties, the evolution of eddy properties, seasonal and interannual variabilities of eddy activities are analyzed in this area. Eddies exist principally in the western Bay of Bengal and most of them propagate westward. The polarity distribution of eddies shows cyclones prefer to occur in the northwest and south of the Bay of Bengal, while anticyclones mainly occur in the east of the bay. Five hundred and sixty-five cyclones and 389 anticyclones with the lifetime that exceeds 30 d are detected during the 22 a period, and there is a preference for the cyclones for all lifetime and propagation distances. The kinetic properties of all observed eddies show the average amplitude of the cyclones is larger than that of the anticyclones, whereas that is opposite for average radius, and their average velocities are basically the same. Moreover, the evolution of eddies properties reveals that the eddies with a long lifetime that exceeds 90 d have a significant double-stage feature of the former 50 d growth period and the dying period after 50 d. For the seasonal variability of the eddies, the cyclones occur more often in spring while the anticyclones occur more often in summer. The analysis of long-lived eddy seasonal distributions shows that there is the obvious seasonal variation of the eddy activities in the Bay of Bengal. The interannual variability of an eddy number shows an obvious negative correlation with the EKE variation. |
| 中文摘要: |
| 本文使用一种基于SLA数据的涡旋识别方法，通过22年的AVISO高度计测高数据对孟加拉湾的中尺度涡特征进行了研究。本文主要分析了孟加拉湾涡旋的地理分布、涡旋极性、涡旋生命周期和传播距离、涡旋产生和消失位置、涡旋传播方向和移动轨迹、涡旋运动特征、涡旋属性的演化以及涡旋活动的季节和年际变化等特性。涡旋主要分布在孟加拉湾西部海域，并且大部分涡旋向西移动。涡旋极性分布显示气旋涡更经常出现在湾的西北部和南部，而反气旋涡主要出现在湾的东部。在22年间，共追踪探测到生命周期超过30天的气旋涡565个、反气旋涡389个；对所有生命周期和传播距离而言都是气旋涡数量居多。所有观测到的涡旋的运动属性分析显示气旋涡的涡旋平均振幅大于反气旋涡；对平均半径和平均移动速度而言，气旋涡和反气旋涡相差不大。而且，涡旋属性演化显示生命周期超过90天的涡旋具有明显的双阶段演化特征，包括一个前50天的涡旋成长阶段和一个50天之后的涡旋消亡阶段。针对涡旋活动的季节变化，气旋涡在春季居多而反气旋涡在夏季较多；长生命周期的涡旋季节分布显示在孟加拉湾涡旋活动具有明显的季节分布特征。涡旋数量的年际变化与EKE变化有一个明显的负相关。 |
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