scholarly journals Modeling low‐frequency volume reverberation from fish for the February–March 1992 Gulf of Alaska surface scatter experiment

1992 ◽  
Vol 92 (4) ◽  
pp. 2479-2479 ◽  
Author(s):  
Redwood W. Nero
Keyword(s):  
Low Frequency ◽  
Gulf Of Alaska ◽  
Surface Scatter ◽  
Scatter Experiment

Low-Frequency Variations in Currents near the Shelf Break: Northeast Gulf of Alaska

1981 ◽  
Vol 11 (5) ◽  
pp. 627-638 ◽  
Author(s):  
Gary S. E. Lagerloef ◽  
Robin D. Muench ◽  
James D. Schumacher
Keyword(s):  
Low Frequency ◽  
Gulf Of Alaska ◽  
Shelf Break ◽  
Frequency Variations

scholarly journals SOURCE MECHANISM OF THE TSUNAMI OP MARCH 28, 1964 IN ALASKA

1964 ◽  
Vol 1 (9) ◽  
pp. 10 ◽  
Author(s):  
W.M. G. Van Dorn
Keyword(s):  
Low Frequency ◽  
Gulf Of Alaska ◽  
Prince William Sound ◽  
Early Effect ◽  
Negative Pole ◽  
The Pacific ◽  
The Times ◽  
The Trinity ◽  
Tsunami Record ◽  
Frequency Character

The distribution of permanent, vertical crustal dislocations, the times and directions of early water motion in and around the generation area, and the unusual low frequency character of the tsunami record obtained from Wake Island, all suggest that the tsunami associated with the great Alaskan earthquake of March 28, 1964 was produced by a dipolar movement of the earth's crust, centered along a line running from Hinchinbrook Island (Prince William Sound) southwesterly to the Trinity Islands. The positive pole of this disturbance encompassed most of the shallow shelf bordering the Gulf of Alaska, while the negative pole lay mostly under land. Thus, the early effect was the drainage of water from the shelf into the Gulf, thus generating a long solitary wave, which radiated out over the Pacific with very little dispersion. Tilting of Prince William Sound to the northwest produced strong seiching action in the deep, narrow adjacent fjords, thus inundating inhabited places already suffering from earth shock and slumping of the deltas on which they were situated. Preliminary calculations indicate that the initial positive phase of the tsunami contained about 2.3 x 102lergs of energy, as compared with 2.7 x 1022ergs computed for the tsunami of March 9, 1957 in the Andreanof Islands.

scholarly journals Low-frequency variability in the Gulf of Alaska from coarse and eddy-permitting ocean models

2009 ◽  
Vol 114 (C1) ◽  
Author(s):  
Antonietta Capotondi ◽  
Vincent Combes ◽  
Michael A. Alexander ◽  
Emanuele Di Lorenzo ◽  
Arthur J. Miller
Keyword(s):  
Low Frequency ◽  
Gulf Of Alaska ◽  
Low Frequency Variability ◽  
Ocean Models

Low-Frequency Pycnocline Variability in the Northeast Pacific

2005 ◽  
Vol 35 (8) ◽  
pp. 1403-1420 ◽  
Author(s):  
Antonietta Capotondi ◽  
Michael A. Alexander ◽  
Clara Deser ◽  
Arthur J. Miller
Keyword(s):  
Simple Model ◽  
General Circulation ◽  
Large Scale ◽  
Broad Band ◽  
Low Frequency ◽  
Circulation Model ◽  
Gulf Of Alaska ◽  
Ekman Pumping ◽  
Mean Flow ◽  
Northeast Pacific

Abstract The output from an ocean general circulation model (OGCM) driven by observed surface forcing is used in conjunction with simpler dynamical models to examine the physical mechanisms responsible for interannual to interdecadal pycnocline variability in the northeast Pacific Ocean during 1958–97, a period that includes the 1976–77 climate shift. After 1977 the pycnocline deepened in a broad band along the coast and shoaled in the central part of the Gulf of Alaska. The changes in pycnocline depth diagnosed from the model are in agreement with the pycnocline depth changes observed at two ocean stations in different areas of the Gulf of Alaska. A simple Ekman pumping model with linear damping explains a large fraction of pycnocline variability in the OGCM. The fit of the simple model to the OGCM is maximized in the central part of the Gulf of Alaska, where the pycnocline variability produced by the simple model can account for ∼70%–90% of the pycnocline depth variance in the OGCM. Evidence of westward-propagating Rossby waves is found in the OGCM, but they are not the dominant signal. On the contrary, large-scale pycnocline depth anomalies have primarily a standing character, thus explaining the success of the local Ekman pumping model. The agreement between the Ekman pumping model and OGCM deteriorates in a large band along the coast, where propagating disturbances within the pycnocline, due to either mean flow advection or boundary waves, appear to play an important role in pycnocline variability. Coastal propagation of pycnocline depth anomalies is especially relevant in the western part of the Gulf of Alaska, where local Ekman pumping-induced changes are anticorrelated with the OGCM pycnocline depth variations. The pycnocline depth changes associated with the 1976–77 climate regime shift do not seem to be consistent with Sverdrup dynamics, raising questions about the nature of the adjustment of the Alaska Gyre to low-frequency wind stress variability.

Low‐frequency distant surface/near‐surface reverberation measurements in the Gulf of Alaska

1992 ◽  
Vol 92 (4) ◽  
pp. 2479-2479
Author(s):  
Roger C. Gauss ◽  
Raymond J. Soukup ◽  
C. Scott Hayek
Keyword(s):  
Low Frequency ◽  
Gulf Of Alaska ◽  
Near Surface

scholarly journals Varied Expressions of the Hemispheric Circulation Observed in Association with Contrasting Polarities of Prescribed Patterns of Variability*

2004 ◽  
Vol 17 (21) ◽  
pp. 4245-4253 ◽  
Author(s):  
R. Quadrelli ◽  
J. M. Wallace
Keyword(s):  
Sea Level ◽  
Intraseasonal Variability ◽  
Low Frequency ◽  
Nonlinear Behavior ◽  
Zonal Flow ◽  
Gulf Of Alaska ◽  
Eastern United States ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
Teleconnection Patterns

Abstract The low-frequency (>5 day period) variability observed within four different subsets of the climatology (H1, L1, H2, and L2) as defined by the high and low index polarities of the two leading principal components (PCs) of the sea level pressure field is compared, with emphasis on distinctive flow configurations and teleconnection patterns. The analysis is based on wintertime 500-hPa height, sea level pressure, and 1000–500-hPa thickness fields derived from the NCEP–NCAR reanalyses for the period of record, 1958–99. “Spaghetti diagrams” display specified contours for ensembles of individual 10-day mean charts extracted from the four different subsets of the climatology. In L1, 10-day mean maps (weak zonal flow at latitudes ∼55°N) exhibit larger undulations in the barotropic component of the flow than those in H1, implying larger particle displacements and deeper penetration of Arctic air masses, particularly into Europe and the eastern United States. Maps in H2 and L2, separated in accordance with the Pacific–North American (PNA)-like second mode, exhibit quite different kinds of planetary wave patterns. The L2 subset (characterized by a retracted Pacific jet) exhibits greater variability over the Gulf of Alaska and over northern Europe. Cold air outbreaks in Europe occur more frequently in L1 than H1, and over western North America, they occur more frequently in L2 than H2. The cold anomalies associated with low polarities of both PCs are observed more frequently than expected based on linear correlation; within the individual subsets of the climatology there are suggestions of multiple circulation regimes; teleconnection patterns for the subsets of the climatology are also discernibly different. These results constitute evidence of nonnormal or nonlinear behavior of 5- and 10-day mean fields and provide indications of how the intraseasonal variability depends on the mean state of the flow in which it is embedded.

Low‐frequency volume scatter and accompanying bioacoustic measurements in the Gulf of Alaska

1992 ◽  
Vol 92 (4) ◽  
pp. 2479-2479
Author(s):  
Mark J. Vaccaro ◽  
Joseph M. Monti ◽  
Al Brooks
Keyword(s):  
Low Frequency ◽  
Gulf Of Alaska
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