| YU Peilong,ZHANG Lifeng,LIU Hu,LIU Xing,ZHU Juan. 2017. A dual-period response of the Kuroshio Extension SST to Aleutian Low activity in the winter season. Acta Oceanologica Sinica, 36(9):1－9 |
| A dual-period response of the Kuroshio Extension SST to Aleutian Low activity in the winter season |
| 冬季黑潮延伸体海表温度对阿留申低压活动的双周期响应 |
| Received:October 12, 2016 |
| DOI：10.1007/s13131-017-1104-1 |
| Key words:sea surface temperature Kuroshio Extension Aleutian Low activity dual-period variability |
| 中文关键词: 海表温度(SST) 黑潮延伸体(KE) 阿留申低压(AL)活动 双周期变率 |
| 基金项目:The National Basic Research Program (973 Program) of China under contract No. 2013CB956203; the National Natural Science Foundation of China under contract No. 41375063; the Junior Fellowships for CAST Advanced Innovation Think-tank Program under contract No. DXB-ZKQN-2016-019. |
| Author Name | Affiliation | E-mail | | YU Peilong | College of Meteorology and Oceanography, National University of Defense Technology, Nanjing 211101, China | | | ZHANG Lifeng | College of Meteorology and Oceanography, National University of Defense Technology, Nanjing 211101, China | zhanglif_qxxy@sina.cn | | LIU Hu | No. 61741 Troops of PLA, Beijing 100025, China | | | LIU Xing | Maritime Environment Project Office, Beijing 100081, China | | | ZHU Juan | Maritime Environment Project Office, Beijing 100081, China | |
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| Abstract: |
| Based on our previous work, the winter sea surface temperature (SST) in the Kuroshio Extension (KE) region showed significant variability over the past century with periods of ~6 a between 1930 and 1950 and ~10 a between 1980 and 2009. How the activity of the Aleutian Low (AL) induces this dual-period variability over the two different timespans is further investigated here. For the ~6 a periodicity during 1930-1950, negative wind stress curl (WSC) anomalies in the central subtropical Pacific associated with an intensified AL generate positive sea surface height (SSH) anomalies. When these wind-induced SSH anomalies propagate westwards to the east of Taiwan, China two years later, positive velocity anomalies appear around the Kuroshio to the east of Taiwan and then the mean advection via this current of velocity anomalies leads to a strengthened KE jet and thus an increase in the KE SST one year later. For the ~10 a periodicity during 1980-2009, a negative North Pacific Oscillation-like dipole takes 2-3 a to develop into a significant positive North Pacific Oscillation-like dipole, and this process corresponds to the northward shift of the AL. Negative WSC anomalies associated with this AL activity in the central North Pacific are able to induce the positive SSH anomalies. These oceanic signals then propagate westward into the KE region after 2-3 a, favoring a northward shift of the KE jet, thus leading to the warming of the KE SST. The feedbacks of the KE SST anomaly on the AL forcing are both negative for these two periodicities. These results suggest that the dual-period KE SST variability can be generated by the two-way KE-SST-AL coupling. |
| 中文摘要: |
| Yu et al.(2016)的研究表明在过去一个世纪里，冬季黑潮延伸体(KE)海表温度(SST)在1930-1950年间呈现出显著的准6年周期变化，而在1980-2009年间呈现出显著的准10年周期变化。本文在该研究的基础上进一步研究了阿留申低压(AL)活动影响KE SST双周期变化的物理过程。对于1930-1950年间的KE SST准6年变化，与AL增强有关的风应力旋度(WSC)异常在副热带中太平洋激发出正的海表高度(SSH)异常。这些海洋信号在2年后西传至台湾以东黑潮导致该区域出现正的速度异常，随后黑潮平均流将这些速度异常在一年后平流至下游KE区，引起KE射流的变强以及KE SST的增暖。对于1980-2009年间的KE SST准10年变化，负的北太平洋涛动偶极分布型在2-3年后演变发展成正的显著北太平洋涛动偶极分布型，该过程对应于AL的北移。与这种AL活动有关的WSC异常在中北太平洋激发出正的SSH异常，随后这些SSH异常在2-3年后西传至KE区，引起KE射流的北移进而导致KE SST的升高。在两个周期上，KE SST异常对AL强迫都呈现出负反馈。这些结果表明KE SST和AL活动间的双向耦合是引起KE SST双周期变率的可能原因。 |
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