Climate change shifts the North Pacific storm track polewards

Area of Science:

• Climatology
• Oceanography
• Atmospheric Science

Background:

• The mid-latitude storm track in the North Pacific is crucial for heat and moisture transport.
• Projected poleward shifts by century's end have significant implications for Arctic and North American climate, ecosystems, and water resources.
• Previous studies indicated a poleward shift, but observational data was lacking.

Purpose of the Study:

• To derive an observational constraint for mid-latitude storm tracks.
• To determine if the North Pacific storm track has shifted poleward in recent decades.
• To assess the role of climate change in storm track positioning and project future impacts.

Main Methods:

• Developed an observational constraint for mid-latitude storm tracks.
• Analyzed atmospheric reanalyses and wind records.
• Compared observed shifts with climate model projections.

Main Results:

• The winter North Pacific storm track has demonstrably shifted poleward, exceeding natural variability.
• A poleward shift in storm track-induced heat and moisture flux is observed over western North America.
• Climate models underestimate the recent poleward storm track shift.

Conclusions:

• The observed poleward shift has significant implications for regional precipitation and temperature patterns.
• Future human-induced impacts on the North Pacific ecosystem and western North America may be underestimated by current climate models.