The present study identifies a close linkage between spring (MAM) sea ice concentration (SIC) anomalies in the Greenland-Barents (GB) Seas and the tropical cyclone (TC) genesis frequency over the eastern North Pacific (ENP) in the subsequent summer and fall (JJASON) during 1979–2022. An increase in MAM GB SIC anomalies results in a decrease in subsequent JJASON ENP TC genesis frequency. The physical process for the influence of Arctic sea ice anomalies on TC formation is further examined. Detailed dynamical diagnosis reveals that a higher GB SIC during MAM results in an increase in upward shortwave radiation, leading to sea surface temperature (SST) cooling. This SST cooling triggers a teleconnection atmospheric wave train, traversing Eurasia, the northern Pacific and the northern America and reaching the northern Atlantic. The associated anomalous cyclone over mid-latitude northern Atlantic is accompanied by anomalous southwesterly winds over the subtropics, leading to SST warming in the subtropical northern Atlantic through weakening total wind speed and upward surface latent heat flux. SST warming in the subtropical northern Atlantic extends southward into the tropical Atlantic via wind-evaporation-SST feedback during the subsequent summer and autumn, which induces an anomalous zonal-vertical circulation with descending motion over the ENP. This descending motion reduces relative humidity and weakens local convection over the ENP, and thus is unfavorable for TC genesis there. This study suggests that the spring GB SIC could serve as a potential predictor of JJASON ENP TC genesis.

中文翻译：

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北极海冰异常对北太平洋东部热带气旋形成的影响：北大西洋海表层温度异常的作用


本研究确定了格陵兰-巴伦支海 （GB） 海的春季 （MAM） 海冰浓度 （SIC） 异常与 1979-2022 年夏季和秋季北太平洋东部 （ENP） 的热带气旋 （TC） 生成频率 （JJASON） 之间的密切联系。MAM GB SIC 异常的增加导致随后的 JJASON ENP TC 发生频率降低。进一步研究了北极海冰异常对 TC 形成影响的物理过程。详细的动力学诊断表明，MAM 期间较高的 GB SIC 导致向上短波辐射增加，从而导致海面温度 （SST） 冷却。这种 SST 冷却触发了遥相关大气波列车，穿越欧亚大陆、北太平洋和北美洲，到达北大西洋。相关的北大西洋中纬度异常气旋伴随着亚热带异常的西南风，通过减弱总风速和向上的表面潜热通量，导致北大西洋副热带海温变暖。在随后的夏季和秋季，副热带北大西洋的 SST 变暖通过风-蒸发-SST 反馈向南延伸到热带大西洋，这引起了在 ENP 上空下降运动的异常纬向垂直环流。这种下降运动降低了相对湿度并削弱了 ENP 上的局部对流，因此不利于 TC 在那里的发生。本研究表明，春季 GB SIC 可作为 JJASON ENP TC 发生的潜在预测因子。