Apr 2, 2016

The stratospheric pathway for Arctic impacts on midlatitude climate

by
Nakamura, Tetsu, Yamazaki, Koji, Iwamoto, Katsushi, Honda, Meiji, Miyoshi, Yasunobu, Ogawa, Yasunobu, Tomikawa, Yoshihiro, Ukita, Jinro
,
Geophysical Research Letters
  • States that recent evidence from both observations and model simulations suggests that an Arctic sea ice reduction tends to cause a negative Arctic Oscillation (AO) phase with severe winter weather in the Northern Hemisphere, which is often preceded by weakening of the stratospheric polar vortex
  • States that although this evidence hints at a stratospheric involvement in the Arctic-midlatitude climate linkage, the exact role of the stratosphere remains elusive
  • Shows that tropospheric AO response to the Arctic sea ice reduction largely disappears when suppressing the stratospheric wave mean flow interactions in numerical experiments
  • Results confirm a crucial role of the stratosphere in the sea ice impacts on the midlatitudes by coupling between the stratospheric polar vortex and planetary-scale waves
  • The results and consistency with observation-based evidence suggest that a recent Arctic sea ice loss is linked to midlatitudes extreme weather events associated with the negative AO phase