Apr 2, 2016

The stratospheric pathway for Arctic impacts on midlatitude climate

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