Wintertime sea surface temperature front around the Kuroshio Extension and its impact on North Pacific blocking
Wintertime sea surface temperature front around the Kuroshio Extension and its impact on North Pacific blocking
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DOI：
10.1002/joc.6937
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发表时间：
2020-11
期刊：
影响因子：
--
通讯作者：
Zhihui Che;Yao Yao-Yao;Linhao Zhong
中科院分区：
文献类型：
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作者：
Zhihui Che;Yao Yao-Yao;Linhao Zhong
利用观测资料和再分析资料，分析了冬季黑潮延伸体（KE）附近海表温度（SST）锋对北太平洋阻塞的影响。KE海面高度异常的偶极型导致黑潮和Oyashio延伸区SST锋（KOEF）和KE SST锋的相反变化。综合分析表明，KOEF可能影响冬季北太平洋阻塞的频率、持续时间、位置、强度和移动。强（弱）KOEF倾向于抑制（促进）大气阻塞的发生，这可能是由于加强（减弱）背景中纬度纬向风。在弱KOEF年份，阻塞往往具有较长的生命周期、准静止状态和较强的振幅。当KOEF较强时，阻塞高压有继续向西移的趋势，但幅度减弱。强的KOEF有利于加强锋面区域的异常湍流热通量释放，截断低气压的局部锚定，以及阻塞偶极子强度和移动的强迫变化。还调查了与KOEF联系的北太平洋阻塞对北美寒流的贡献。
The influence of the wintertime sea surface temperature (SST) fronts around the Kuroshio Extension (KE) on North Pacific blocking is analysed using observational and reanalysis data. The dipole pattern of sea surface height anomalies in the KE induces opposite changes in the Kuroshio and Oyashio Extension SST front (KOEF) and the KE SST front. Composite analysis shows that the KOEF may affect the frequency, duration, location, intensity and movement of wintertime North Pacific blocking. A strong (weak) KOEF tends to inhibit (promote) the genesis of atmospheric blocking, which might be due to intensified (weakening) background mid‐latitude zonal wind. In weak‐KOEF years, blocking tends to have a long life cycle, quasi‐stationary state and intensified amplitude. However, when the KOEF is strong, the blocking high tends to move continuously westward with a weakened amplitude. A strong KOEF is conducive to a strengthened anomalous turbulent heat flux release over the front region, localized anchoring of the cut‐off low, and the forcing of a change in the intensity and movement of the blocking dipole. Also investigated are the contributions to cold spells over North America attributable to the North Pacific blockings link with the KOEF.