TY - JOUR
T1 - Enhanced interactions of Kuroshio Extension with tropical Pacific in a changing climate
AU - Joh, Youngji
AU - Di Lorenzo, Emanuele
AU - Siqueira, Leo
AU - Kirtman, Benjamin P.
N1 - Funding Information:
Youngji Joh and Emanuele Di Lorenzo acknowledge the support of the DOE-RGMA grant. Leo Siqueira and Ben Kirtman acknowledge funding from the U.S. National Science Foundation (NSF; OCE 132022, OCE1419569), NOAA (NA18OAR4310293, NA15OAR4320064), and DOE (DE-SC0019418, DE-SC0019433). Model experiments were performed using computing resources provided by the University of Miami Center for Computational Science (UM-CCS) and by the Climate Simulation Laboratory (ark:/85065/d7wd3xhc) at NCAR’s Computational and Information Systems Laboratory (NCAR-CISL), sponsored by the National Science Foundation and other agencies. The source code for the model used in this study, the NCAR-CCSM4, is freely available at http://www. cesm.ucar.edu/models/ccsm4.0/. The model data are archived at the UM-CCS.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - Quasi-decadal climate of the Kuroshio Extension (KE) is pivotal to understanding the North Pacific coupled ocean–atmosphere dynamics and their predictability. Recent observational studies suggest that extratropical-tropical coupling between the KE and the central tropical Pacific El Niño Southern Oscillation (CP-ENSO) leads to the observed preferred decadal time-scale of Pacific climate variability. By combining reanalysis data with numerical simulations from a high-resolution climate model and a linear inverse model (LIM), we confirm that KE and CP-ENSO dynamics are linked through extratropical-tropical teleconnections. Specifically, the atmospheric response to the KE excites Meridional Modes that energize the CP-ENSO (extratropicstropics), and in turn, CP-ENSO teleconnections energize the extratropical atmospheric forcing of the KE (tropicsextratropics). However, both observations and the model show that the KE/CP-ENSO coupling is non-stationary and has intensified in recent decades after the mid-1980. Given the short length of the observational and climate model record, it is difficult to attribute this shift to anthropogenic forcing. However, using a large-ensemble of the LIM we show that the intensification in the KE/CP-ENSO coupling after the mid-1980 is significant and linked to changes in the KE atmospheric downstream response, which exhibit a stronger imprint on the subtropical winds that excite the Pacific Meridional modes and CP-ENSO.
AB - Quasi-decadal climate of the Kuroshio Extension (KE) is pivotal to understanding the North Pacific coupled ocean–atmosphere dynamics and their predictability. Recent observational studies suggest that extratropical-tropical coupling between the KE and the central tropical Pacific El Niño Southern Oscillation (CP-ENSO) leads to the observed preferred decadal time-scale of Pacific climate variability. By combining reanalysis data with numerical simulations from a high-resolution climate model and a linear inverse model (LIM), we confirm that KE and CP-ENSO dynamics are linked through extratropical-tropical teleconnections. Specifically, the atmospheric response to the KE excites Meridional Modes that energize the CP-ENSO (extratropicstropics), and in turn, CP-ENSO teleconnections energize the extratropical atmospheric forcing of the KE (tropicsextratropics). However, both observations and the model show that the KE/CP-ENSO coupling is non-stationary and has intensified in recent decades after the mid-1980. Given the short length of the observational and climate model record, it is difficult to attribute this shift to anthropogenic forcing. However, using a large-ensemble of the LIM we show that the intensification in the KE/CP-ENSO coupling after the mid-1980 is significant and linked to changes in the KE atmospheric downstream response, which exhibit a stronger imprint on the subtropical winds that excite the Pacific Meridional modes and CP-ENSO.
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U2 - 10.1038/s41598-021-85582-y
DO - 10.1038/s41598-021-85582-y
M3 - Article
C2 - 33737564
AN - SCOPUS:85102703100
VL - 11
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
IS - 1
M1 - 6247
ER -