Sensitivity of the Latitude of the Westerly Jet Stream to Climate Forcing
Abstract The latitude of the westerly jet stream is influenced by a variety of climate forcings, but their effects on the jet latitude often manifest as a tug of war between tropical forcing (e.g., tropical upper‐tropospheric warming) and polar forcing (e.g., Antarctic stratospheric cooling or Arcti...
| Published in: | Geophysical Research Letters |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2020
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| Subjects: | |
| Online Access: | https://doi.org/10.1029/2019GL086563 https://doaj.org/article/51f75b50716d425796b7561f9a45af00 |
| Summary: | Abstract The latitude of the westerly jet stream is influenced by a variety of climate forcings, but their effects on the jet latitude often manifest as a tug of war between tropical forcing (e.g., tropical upper‐tropospheric warming) and polar forcing (e.g., Antarctic stratospheric cooling or Arctic amplification). Here we present a unified forcing‐feedback framework relating different climate forcings to their forced jet changes, in which the interactions between the westerly jet and synoptic eddies are synthesized by a zonal advection feedback, analogous to the feedback framework for assessing climate sensitivity. This framework is supported by a prototype feedback analysis in the atmospheric dynamical core of a climate model with diverse thermal and mechanical forcings. Our analysis indicates that the latitude of a westerly jet is most sensitive to the climate change‐induced jet speed changes near the tropopause. The equatorward jet shift also displays a larger deviation from linearity than the poleward counterpart. |
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