Details:

Journal Title:
Journal of Climate
Personal Author:
Zhang, Liping ; Delworth, Thomas L.
Zhang, Liping ; Delworth, Thomas L. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; GFDL (Geophysical Fluid Dynamics Laboratory) ; CICSP (Cooperative Institute for Climate Science)
OAR (Oceanic and Atmospheric Research) ; GFDL (Geophysical Fluid Dynamics Laboratory) ; CICSP (Cooperative Institute for Climate Science) Less -
Description:
The impact of climate change on the Pacific decadal oscillation (PDO) is studied using a fully coupled climate model. The model results show that the PDO has a similar spatial pattern in altered climates, but its amplitude and time scale of variability change in response to global warming or cooling. In response to global warming the PDO amplitude is significantly reduced, with a maximum decrease over the Kuroshio–Oyashio Extension (KOE) region. This reduction appears to be associated with a weakened meridional temperature gradient in the KOE region. In addition, reduced variability of North Pacific wind stress, partially due to reduced air–sea feedback, also helps to weaken the PDO amplitude by reducing the meridional displacements of the subtropical and subpolar gyre boundaries. In contrast, the PDO amplitude increases in response to global cooling.

In the control simulations the model PDO has an approximately bidecadal peak. In a warmer climate the PDO time scale becomes shorter, changing from ~20 to ~12 yr. In a colder climate the time scale of the PDO increases to ~34 yr. Physically, global warming (cooling) enhances (weakens) ocean stratification. The increased (decreased) ocean stratification acts to increase (reduce) the phase speed of internal Rossby waves, thereby altering the time scale of the simulated PDO.


Keywords:
[+]
Decadal variability
Source:
Journal of Climate, 29(16), 5999-6018
DOI:
https://doi.org/10.1175/JCLI-D-15-0690.1
Document Type:
Journal Article
Rights Information:
Other
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:89d01f38e3f688ec24f7eec23b7ddf0d197951a5a381284bb879b0ea392d2f08
Download URL:
https://repository.library.noaa.gov/view/noaa/29868/noaa_29868_DS1.pdf
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