This study investigates the concurrent location and intensity changes of the East Asian polar front jet (EAPJ) and subtropical jet (EASJ) on decadal time scale using NCEP/NCAR, ERA5 and JRA-55 reanalysis data, along with the relationship with the mid-high latitude circulation changes. Results show that EAPJ was intensified accompanied by the weakening of EASJ after 1985, and shifted equatorward in conjunction with the poleward migration of EASJ after 1999. The three-dimensional structures of the atmospheric circulation over East Asia exhibited distinct changes corresponding to the two regime shifts. Dipole anomalous sea level pressure (SLP) between the Arctic and the North Pacific, a NAM-like geopotential height anomalous pattern, and a deepened polar vortex occurred after 1985, accompanied with the out-of-phase intensity changes of the two jets. In comparison, dipole SLP anomalies between the mid-high latitudes and Tibetan Plateau, a zonal wave train over Eurasia accompanied with a meridional wave train over East Asia, and a polar vortex shifting toward the Siberia were observed after 1999, when the two jets approached each other. These circulation changes exerted pronounced effects on the East Asian climate anomalies. After the mid-1980s, the positive SLP anomaly over the northern North Pacific led to decreased land-sea SLP contrast, and the positive mid-tropospheric geopotential height center near Lake Baikal implied weakened East Asian trough (EAT). Such changes favored the warming of southern East Asia and the weakening of the southern mode of East Asian winter monsoon (EAWM). In contrast, the high latitude positive SLP anomalies denoted enhanced Siberian high (SH) and the East Asian meridional wave train resulted in tilted EAT after the late 1990s, benefitting the cold anomalies over northern Eurasia with the northern mode of EAWM intensified. Possible mechanisms for the decadal changes of the jets are discussed from the perspective of the dynamic forcing of the synoptic-scale transient eddy activities (STEA), and the thermal forcings from the East Asian landmass, the North Pacific sea surface and the Arctic sea ice cover.

这项研究使用NCEP / NCAR，ERA5和JRA-55再分析数据，以年代际尺度调查了东亚极地锋射流（EAPJ）和副热带高压射流（EASJ）的并发位置和强度变化，以及与中纬度的关系。高纬度环流变化。结果表明，东亚太平洋急流伴随着1985年后东亚急流的减弱而增强，并在1999年后随着东亚急流向极移向赤道移动。东亚地区大气环流的三维结构呈现出明显的变化，对应于两种体制转移。 。北极和北太平洋之间的偶极子异常海平面压力（SLP），类似于NAM的地势高度异常模式和加深的极地涡旋在1985年之后出现，并伴随着两​​个喷流的强度反相位变化。相比之下，在1999年之后，当两架喷气机接近时，观测到中高纬度与青藏高原之间的偶极子SLP异常，欧亚大陆上的纬向波列和东亚上的子午波列以及向西伯利亚的极地涡旋。彼此。这些环流变化对东亚气候异常产生了明显的影响。1980年代中期以后，北太平洋北部的SLP异常正值导致海陆SLP对比度下降，贝加尔湖附近的对流层中位势正高度中心暗示东亚海槽（EAT）减弱。这种变化有利于东亚南部的变暖和东亚冬季风（EAWM）的南部模式的减弱。相比之下，高纬度SLP异常表示西伯利亚高压（SH）增强，东亚子午线波列导致EAT在1990年代后期倾斜，这使欧亚大陆北部的寒冷异常受益于EAWM的北部模式。从天气尺度瞬态涡旋活动（STEA）的动态强迫以及东亚大陆，北太平洋海面和北极海冰的热强迫的角度讨论了喷射器年代际变化的可能机制。覆盖。