Variations of Mid-Pacific Trough and Their Relations to the Asian-Pacific-North American Climate: Roles of Tropical Sea Surface Temperature and Arctic Sea Ice

The mid-Pacific trough (MPT), occurring in the upper troposphere during boreal summer, acts as an atmospheric bridge connecting the climate variations over Asia, the Pacific, and North America. The first (second) mode of empirical orthogonal function analysis of the MPT, which accounts for 20.3 (13....

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Bibliographic Details
Main Authors: Deng, Kaiqiang, Yang, S., Ting, Mingfang, Hu, Chundi, Lu, Mengmeng
Format: Text
Language:unknown
Published: Columbia University 2017
Subjects:
Climatic changes
Ocean temperature
Ocean-atmosphere interaction
Arctic
Bering Strait
Pacific
North Atlantic
Sea ice
Online Access:https://dx.doi.org/10.7916/d8698fzz
https://academiccommons.columbia.edu/doi/10.7916/D8698FZZ
Description
Summary:The mid-Pacific trough (MPT), occurring in the upper troposphere during boreal summer, acts as an atmospheric bridge connecting the climate variations over Asia, the Pacific, and North America. The first (second) mode of empirical orthogonal function analysis of the MPT, which accounts for 20.3 (13.4) percent of the total variance, reflects a change in its intensity on the southwestern (northeastern) portion of the trough. Both modes are significantly correlated with the variability of tropical Pacific sea surface temperature (SST). Moreover, the first mode is affected by Atlantic SST via planetary waves that originate from the North Atlantic and propagate eastward across the Eurasian continent, and the second mode is influenced by the Arctic sea ice near the Bering Strait by triggering an equatorward wave train over the Northeast Pacific. A stronger MPT shown in the first mode is significantly linked to drier and warmer conditions in the Yangtze Basin, southern Japan, and northern U.S. and a wetter condition in South Asia and northern China, while a stronger MPT shown in the second mode is associated with drier and warmer southwestern U.S. In addition, an intensified MPT (no matter in the southwestern or the northeastern portion) corresponds to more tropical cyclones (TCs) over the western North Pacific (WNP) and less TCs over the eastern Pacific (EP) in summer, which is associated with MPT-induced ascending and descending motions over the WNP and the EP, respectively.

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