The Winter Concurrent Meridional Shift of the East Asian Jet Streams and the Associated Thermal Conditions

Abstract

In this study, the concurrent meridional shift of the East Asian polar-front jet (EAPJ) and the East Asian subtropical jet (EASJ) and the associated thermal conditions have been investigated. The concurrent meridional shift is dominantly characterized by an out-of-phase shift of the two jets, as an equatorward shift of the EAPJ and a poleward shift of the EASJ, and vice versa. This shift is linked with the dipole surface air temperature (SAT) anomaly over the Eurasian continent and a La Niña–like sea surface temperature (SST) anomaly. Associated with the dipole SAT anomaly, the meridional temperature gradient (MTG) anomaly exhibits a tripole pattern from low to high latitudes over the Eurasian continent, as well as an enhanced maximum eddy growth rate and an anomalous divergence of Eliassen–Palm flux (E-P flux) over the regions between the EAPJ and EASJ. Additionally, the synoptic-scale transient eddy activities (STEA) significantly decrease over the high latitudes and enhance between the EAPJ and EASJ. All the anomalies would benefit the equatorward and poleward shift of the EAPJ and EASJ, respectively. The MTG, E-P flux and STEA anomalies are also indicated in that associated with the Niña-like SST anomaly. Particularly, the variations are evident in low latitudes. The pathway of the stationary Rossby wave activity flux anomalies shows an eastward Rossby wave packet propagation along the southern portion of the EAPJ is associated with the SAT anomaly and that along the northern portion of the EASJ is associated with the SST anomaly. The relative contributions of the two thermal conditions have emphasized the role of the dipole SAT anomaly, based on multilinear regression.

Synergistic Effects of Midlatitude Atmospheric Upstream Disturbances and Oceanic Subtropical Front Intensity Variability on Western Pacific Jet Stream in Winter

“…The shift of EASJ and EAPJ can reflect the interactions among different circulation systems (Schiemann et al, 2009;Y. C. Zhang & Huang, 2011) and therefore impact the local weather and climate as well as downstream regions (Guan et al, 2019;Y. Z. Zhang, Yan, et al, 2019;Zhou & Yu, 2005;Zhou & Zou, 2010;Zhu & Li, 2016).…”

“…The shift of EASJ and EAPJ can reflect the interactions among different circulation systems (Schiemann et al, 2009; Y. C. Zhang & Huang, 2011) and therefore impact the local weather and climate as well as downstream regions (Guan et al, 2019; Y. Z. Zhang, Yan, et al, 2019; Zhou & Yu, 2005; Zhou & Zou, 2010; Zhu & Li, 2016). Branstator (2002) proved that the winter Asian jet could provide a waveguide for stationary Rossby waves and thus enhance the amplitude of low‐frequency disturbance.…”

“…In cool seasons, EASJ and EAPJ converge over the East Asian coastal waters, and a jet generates and extends eastward into the oceanic region (Koch et al, 2006;Newton, 2004), which is known as WPJS. The shift of EASJ and EAPJ can reflect the interactions among different circulation systems (Schiemann et al, 2009; Y. C. Zhang & Huang, 2011) and therefore impact the local weather and climate as well as downstream regions (Guan et al, 2019;Y. Z. Zhang, Yan, et al, 2019;Zhou & Yu, 2005;Zhou & Zou, 2010;Zhu & Li, 2016).…”

The 10–30‐day oscillation of winter rainfall in southern China and its relationship with circulation patterns in different latitudes

“…Rainfall is determined by both the circulation and the moisture conditions. Subtropical highs, westerlies, and other planetary-scale systems also have intraseasonal, seasonal, interannual, even interdecadal differences (e.g., Chen and Weng, 1999;Teng and Wang, 2003;Yang and Li, 2016;Huang et al, 2017;Huang et al, 2019;Yan et al, 2019;Zhang et al, 2019). According to the quantitative diagnosis method of multiscale interactions , some studies indicated that the rainfall ISO could be affected not only by intraseasonal activities but also by higher frequency disturbances (e.g., Maloney and Dickinson, 2003;Ren et al, 2011;.…”

The decadal shift of the long persistent rainfall over the northern part of China and the associated ocean conditions

“…These SST anomalies affect the precipitation variations via triggering the change of some typical circulations, such as the Silk Road pattern (SRP; Ding et al, 2011 ;He et al, 2017b), the East Asia jet stream (EAJS; Ren et al, 2008;Zhu et al, 2013;Huang et al, 2014;Huang et al, 2019;Zhang et al, 2019), etc. The SST anomalies over the eastern Pacific, particularly the El Niño-Southern Oscillation (ENSO), influenced the precipitation over East Asia by changing the structure of the SRP (Ding et al, 2011;He et al, 2017b).…”