Diversity of the Wintertime Arctic Oscillation Pattern among CMIP5 Models : Role of the Stratospheric Polar Vortex

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review

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Author(s)

  • Hainan GONG
  • Lin WANG
  • Wen CHEN
  • Renguang WU
  • Lin LIU
  • Debashis NATH
  • Xiaoqing LAN

Detail(s)

Original languageEnglish
Pages (from-to)5235-5250
Journal / PublicationJournal of Climate
Volume32
Issue number16
Early online date24 Jul 2019
Publication statusPublished - Aug 2019

Abstract

The wintertime Arctic Oscillation (AO) pattern in phase 5 of the Coupled Model Intercomparison Project (CMIP5) climate models displays notable differences from the reanalysis. The North Pacific center of the AO pattern is larger in the ensemble mean of 27 models than in the reanalysis, and the magnitude of the North Pacific center of the AO pattern varies largely among the models. This study investigates the plausible sources of the diversity of the AO pattern in the models. Analysis indicates that the amplitude of the North Pacific center is associated with the coupling between the North Pacific and North Atlantic, which in turn is primarily modulated by the strength of the stratospheric polar vortex. A comparative analysis is conducted for the strong polar vortex (SPV) and weak polar vortex (WPV) models. It reveals that a stronger stratospheric polar vortex induces more planetary waves to reflect from the North Pacific to the North Atlantic and more wave activity fluxes to propagate from the North Pacific to the North Atlantic in the SPV models than in the WPV models. Thus, the coupling of atmospheric circulation between the North Pacific and North Atlantic is stronger in the SPV models, which facilitates more North Pacific variability to be involved in the AO variability and induces a stronger North Pacific center in the AO pattern. The increase in vertical resolution may improve the simulation of the stratospheric polar vortex and thereby reduces the model biases in the North Pacific-North Atlantic coupling and thereby the amplitude of the North Pacific center of the AO pattern in models.

Research Area(s)

  • Pacific-North American pattern, oscillation, Stratosphere, Model evaluation, performance, Arctic Oscillation, Interannual variability, NORTH-ATLANTIC OSCILLATION, ANNULAR MODE, EXTRATROPICAL CIRCULATION, INTERANNUAL VARIABILITY, PART II, CLIMATE, REPRESENTATION, TROPOSPHERE, SIMULATIONS, TEMPERATURE

Citation Format(s)

Diversity of the Wintertime Arctic Oscillation Pattern among CMIP5 Models : Role of the Stratospheric Polar Vortex. / GONG, Hainan; WANG, Lin; CHEN, Wen; WU, Renguang; ZHOU, Wen; LIU, Lin; NATH, Debashis; LAN, Xiaoqing.

In: Journal of Climate, Vol. 32, No. 16, 08.2019, p. 5235-5250.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review