Impacts of four northern-hemisphere teleconnection patterns on atmospheric circulations over Eurasia and the Pacific

Abstract

The impacts of four teleconnection patterns on atmospheric circulation components over Eurasia and the Pacific region, from low to high latitudes in the Northern Hemisphere (NH), were investigated comprehensively in this study. The patterns, as identified by the Climate Prediction Center (USA), were the East Atlantic (EA), East Atlantic/ Western Russia (EAWR), Polar/Eurasia (POLEUR), and Scandinavian (SCAND) teleconnections. Results indicate that the EA pattern is closely related to the intensity of the subtropical high over different sectors of the NH in all seasons, especially boreal winter. The wave train associated with this pattern serves as an atmospheric bridge that transfers Atlantic influence into the low-latitude region of the Pacific. In addition, the amplitudes of the EAWR, SCAND, and POLEUR patterns were found to have considerable control on the "Vangengeim-Girs" circulation that forms over the AtlanticEurasian region in winter or spring. The EA and EAWR mainly affect the westerlies in winter and spring and the POLEUR and SCAND, respectively, in summer and winter. Strong westerlies confine the extension of the North Polar vortex, which generally results in a small weak vortex and a shallow East Asian trough located in a position further east than normal. Furthermore, the North Polar vortex presents significant connections with the patterns during winter and summer. Analyses in this work suggest that the teleconnection patterns in summer could be driven, at least partly, by the Atlantic Multidecadal Oscillation, which to some degree might transmit the influence of the Atlantic Ocean to Eurasia and the Pacific region.

The changing influences of the AMO and PDO on the decadal variation of the Santa Ana winds

“…This study does not look into the physical processes that enable the AMO to influence the SLP variations over the Great Basin and the subtropical Pacific; however, prior studies have offered clues on the possible processes for the influence. For example, Zhang and Delworth (2007) suggested that the AMO can impact the North Pacific climate by altering the latitudinal location of the mid-latitude jetstream, while Yu et al (2015) and Gao et al (2016) noticed that the positive phase of the AMO can intensify the PSH. The mass redistribution associated with such a location shift and intensification may affect the strength of the SLP over the Great Basin and subtropical Pacific.…”

A comprehensive analysis of coherent rainfall patterns in China and potential drivers. Part I: Interannual variability

“…Other northern-hemisphere teleconnection patterns that are not zonally aligned but have arc-like shapes include the East Atlantic, East Atlantic/Western Russia, Polar/Eurasia, and Scandinavian patterns. Their influence on the atmospheric circulation over Eurasia and the Pacific was examined by Tao et al (2016). A wave train resembling the Scandinavian pattern was also identified by Wang and Feng (2011) who found that winter precipitation in south China is associated with a barotropic wave train originating over the Atlantic.…”

Characteristics of atmospheric circulation patterns over East Asia and their impacts on precipitation in summer

“…The im pacts of the EAWR pattern on the climate reach the mid-latitudes of East Asia as a planetary-scale stationary wave pattern (Krichak et al 2014), and the EAWR pattern is closely linked to summer precipitation over East Asia (Gao et al 2017, Tan & Shao 2017. Regarding the positive EWD pattern, an increase in its frequency leads to anomalous northerly flows prevailing in eastern China and significant anomalous easterly winds from the Bay of Bengal to the western Pacific, reducing the northward propagation of southerly water vapor transport from the tropics and leading to below-average precipitation in northern China (Figs.…”