Uncertainty in Future Projections of the North Pacific Subtropical High and its Implication for California Winter Precipitation Change

TitleUncertainty in Future Projections of the North Pacific Subtropical High and its Implication for California Winter Precipitation Change
Publication TypeJournal Article
Year of Publication2016
JournalJournal of Geophysical Research: Atmospheres
Volume121
Number2
Pages795-806
Date Published02/2016
Abstract / Summary

This study examines future projections of sea level pressure change in the North Pacific and its impact on winter precipitation changes in California. The multimodel analysis, based on the Coupled Model Intercomparison Project phase 5 models under the Representative Concentration Pathway 8.5 scenario, shows a robust sea level pressure change in the late 21st century over the western North Pacific in which both the Aleutian Low and the North Pacific subtropical high (NPSH) shift poleward in concert with a widening of the Hadley cell. This change is partly explained by a systematic increase of static stability in the subtropics. Despite its robustness, the projected NPSH changes over the eastern North Pacific exhibit a substantial intermodel spread, contributing as a cause for uncertain projections of precipitation changes in California. This intermodel spread in the eastern North Pacific is associated with a Pacific Decadal Oscillation-like surface temperature change in the western North Pacific and the resulting meridional temperature gradient change. This study points to a major source of uncertainty for the response of winter precipitation to global warming over the West Coast of North America: atmosphere-ocean coupling in the North Pacific.

URLhttp://onlinelibrary.wiley.com/wol1/doi/10.1002/2015JD023858/full
DOI10.1002/2015JD023858
Journal: Journal of Geophysical Research: Atmospheres
Year of Publication: 2016
Volume: 121
Number: 2
Pages: 795-806
Date Published: 02/2016

This study examines future projections of sea level pressure change in the North Pacific and its impact on winter precipitation changes in California. The multimodel analysis, based on the Coupled Model Intercomparison Project phase 5 models under the Representative Concentration Pathway 8.5 scenario, shows a robust sea level pressure change in the late 21st century over the western North Pacific in which both the Aleutian Low and the North Pacific subtropical high (NPSH) shift poleward in concert with a widening of the Hadley cell. This change is partly explained by a systematic increase of static stability in the subtropics. Despite its robustness, the projected NPSH changes over the eastern North Pacific exhibit a substantial intermodel spread, contributing as a cause for uncertain projections of precipitation changes in California. This intermodel spread in the eastern North Pacific is associated with a Pacific Decadal Oscillation-like surface temperature change in the western North Pacific and the resulting meridional temperature gradient change. This study points to a major source of uncertainty for the response of winter precipitation to global warming over the West Coast of North America: atmosphere-ocean coupling in the North Pacific.

DOI: 10.1002/2015JD023858
Citation:
Choi, J, J Lu, S Son, DM Frierson, and J Yoon.  2016.  "Uncertainty in Future Projections of the North Pacific Subtropical High and its Implication for California Winter Precipitation Change."  Journal of Geophysical Research: Atmospheres 121(2): 795-806.  https://doi.org/10.1002/2015JD023858.