The western boundary currents are characterized by narrow, intense ocean jets and are among the most energetic phenomena in the world ocean. The importance of the western boundary currents to the mean climate is well established: they transport vast quantities of heat from the subtropics to the midlatitudes¹, and they govern the structure of the climatological mean surface winds^2,3,4,5,6, precipitation^4,5,6 and extratropical storm tracks^{7,8,9,10,11,12,13}. Their importance to climate variability is much less clear, as the tropospheric response to extratropical sea surface temperature (SST) variability is generally modest relative to the internal variability in the midlatitude atmosphere^12,13,14. Here we exploit novel local analyses based on high-spatial-resolution data to demonstrate that SST variability in the western boundary currents has a more robust signature in climate variability than has been indicated in previous work. Our results indicate that warm SST anomalies in the major boundary currents of both hemispheres are associated with a distinct signature of locally enhanced precipitation and rising motion anomalies that extend throughout the depth of the troposphere. The tropospheric signature closely mirrors that of ocean dynamical processes in the boundary currents. Thus, the findings indicate a distinct and robust pathway through which extratropical ocean dynamical processes influence local climate variability. The observational relationships are also reproducible in Earth system model simulations but only when the simulations are run at high spatial resolution.

西部边界流的特点是狭窄而强烈的海洋喷射，是世界海洋中能量最强的现象之一。西部边界流对平均气候的重要性是公认的：它们将大量热量从亚热带输送到中纬度¹，它们控制着气候平均地表风^{2、3、4、5、6}、降水^4、5、6 和温带风暴路径^{7、8、9、10、11、12、13} 的结构.它们对气候变率的重要性则不太清楚，因为相对于中纬度大气的内部变率，对流层对温带海面温度 （SST） 变率的响应通常是适度的^12,13,14。在这里，我们利用基于高空间分辨率数据的新型局部分析来证明西部边界流中的 SST 变率比以前的工作中表明的具有更强大的气候变率特征。我们的结果表明，两个半球主要边界流中的暖海温异常与局部增强的降水和延伸到整个对流层深度的上升运动异常的明显特征有关。对流层特征与边界流中的海洋动力学过程密切相关。因此，研究结果表明温带海洋动力学过程影响局部气候变率的途径是独特而稳健的。观测关系在地球系统模型模拟中也是可重现的，但前提是模拟以高空间分辨率运行。