TY - JOUR
T1 - A comparison of remote vs. local influence of El Niño on the coastal circulation of the northeast Pacific
AU - Hermann, Albert J.
AU - Curchitser, Enrique N.
AU - Haidvogel, Dale B.
AU - Dobbins, Elizabeth L.
N1 - Funding Information:
We gratefully acknowledge the expertise of Kate Hedstrom, who was instrumental in creating the NEP grid used here. We further thank all the reviewers for their thorough analysis of an earlier draft of the manuscript. The Forecast Systems Laboratory of NOAA provided computing resources. Main funding for this work was provided by the National Science Foundation Grants OCE00-02893, OCE-0113461 and OCE-0435592. This is contribution 628 from the U.S. Global Ecosystems Dynamics (GLOBEC) Program jointly funded by the National Science Foundation and National Oceanic and Atmospheric Administration, 3129 from the NOAA/Pacific Marine Environmental Laboratory, 1748 from the Joint Institute for the Study of the Atmosphere and Oceans, University of Washington and Eco-FOCI-G713 from the Fisheries Oceanography Coordinated Investigations (FOCI).
PY - 2009/11/15
Y1 - 2009/11/15
N2 - A set of spatially nested circulation models is used to explore interannual change in the northeast Pacific (NEP) during 1997-2002, and remote vs. local influence of the 1997-1998 El Niño on this region. Our nested set is based on the primitive equations of motion, and includes a basin-scale model of the north Pacific at ∼40-km resolution (NPac), and a regional model of the Northeast Pacific at ∼10-km resolution. The NEP model spans an area from Baja California through the Bering Sea, from the coast to ∼2000-km offshore. In this context, "remote influence" refers to effects driven by changes in ocean velocity and temperature outside of the NEP domain; "local influence" refers to direct forcing by winds and runoff within the NEP domain. A base run of this model using hindcast winds and runoff for 1996-2002 replicates the dominant spatial modes of sea-surface height anomalies from satellite data, and coastal sea level from tide gauges. We have performed a series of sensitivity runs with the NEP model for 1997-1998, which analyze the response of coastal sea level to: (1) hindcast winds and coastal runoff, as compared to their monthly climatologies and (2) hindcast boundary conditions (from the NPac model), as compared to their monthly climatologies. Results indicate penetration of sea-surface height (SSH) from the basin-scale model into the NEP domain (e.g., remote influence), with propagation as coastal trapped waves from Baja up through Alaska. Most of the coastal sea-level anomaly off Alaska in El Niño years appears due to direct forcing by local winds and runoff (local influence), and such anomalies are much stronger than those produced off California. We quantify these effects as a function of distance along the coastline, and consider how they might impact the coastal ecosystems of the NEP.
AB - A set of spatially nested circulation models is used to explore interannual change in the northeast Pacific (NEP) during 1997-2002, and remote vs. local influence of the 1997-1998 El Niño on this region. Our nested set is based on the primitive equations of motion, and includes a basin-scale model of the north Pacific at ∼40-km resolution (NPac), and a regional model of the Northeast Pacific at ∼10-km resolution. The NEP model spans an area from Baja California through the Bering Sea, from the coast to ∼2000-km offshore. In this context, "remote influence" refers to effects driven by changes in ocean velocity and temperature outside of the NEP domain; "local influence" refers to direct forcing by winds and runoff within the NEP domain. A base run of this model using hindcast winds and runoff for 1996-2002 replicates the dominant spatial modes of sea-surface height anomalies from satellite data, and coastal sea level from tide gauges. We have performed a series of sensitivity runs with the NEP model for 1997-1998, which analyze the response of coastal sea level to: (1) hindcast winds and coastal runoff, as compared to their monthly climatologies and (2) hindcast boundary conditions (from the NPac model), as compared to their monthly climatologies. Results indicate penetration of sea-surface height (SSH) from the basin-scale model into the NEP domain (e.g., remote influence), with propagation as coastal trapped waves from Baja up through Alaska. Most of the coastal sea-level anomaly off Alaska in El Niño years appears due to direct forcing by local winds and runoff (local influence), and such anomalies are much stronger than those produced off California. We quantify these effects as a function of distance along the coastline, and consider how they might impact the coastal ecosystems of the NEP.
KW - Coastal currents
KW - Coastal oceanography
KW - El Niño phenomena
KW - Mathematical models
KW - Northeast Pacific
KW - Physical oceanography
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U2 - 10.1016/j.dsr2.2009.02.005
DO - 10.1016/j.dsr2.2009.02.005
M3 - Article
AN - SCOPUS:71749113190
SN - 0967-0645
VL - 56
SP - 2427
EP - 2443
JO - Deep-Sea Research Part II: Topical Studies in Oceanography
JF - Deep-Sea Research Part II: Topical Studies in Oceanography
IS - 24
ER -