El ano 2006 representa en dos sentidos una fecha critica para la cuenca del Rio Columbia y para los esfuerzos de recuperacion del salmon y la trucha arcoiris en la region Pacifico Noroeste: el 25 aniversario de la creacion del Consejo para la Conservacion y Poder del Noroeste y el...
We examined variability in growth rate during the larval stage of northern anchovy (Engraulis mordax) in response to physical and biological environmental factors in 2005 and 2006. The onset of spring upwelling was anomalously delayed by 2–3 months until mid-July in 2005; in contrast, spring upwelling in 2006 began as...
Submersible belt-transect surveys along a rocky bottom were combined with acoustic surveys of the water column to estimate depth distribution and density of fishes at Stonewall Bank, Oregon in the northeastern Pacific Ocean from September through October 1991. The objectives of the study were to determine the proportion of fish...
Microstructure observations near upwelled fronts indicate considerable variation in the structure of
vertical mixing across the frontal region. Observations of cool filaments off northern California
indicate that within the cool (dense) core of filaments the raised pycnocline inhibits the penetration to
middepths of surface-generated mixing. The microstructure profiles are used...
Kelvin-Helmholtz (KH) instability, characterized by the distinctive finite-amplitude billows it generates, is an important mechanism in the development of turbulence in the stratified interior of the ocean. In particular, it is often assumed that the onset of turbulence in internal waves begins in this way. Clear recognition of the importance...
Turbulence resulting from Kelvin–Helmholtz instability in layers of localized stratification and shear is studied by means of direct numerical simulation. Our objective is to present a comprehensive description of the turbulence evolution in terms of simple, conceptual pictures of shear–buoyancy interaction that have been developed previously based on assumptions of...
Direct numerical simulations of turbulence resulting from Kelvin–Helmholtz instability in stably
stratified shear flow are used to study sources of anisotropy in various spectral ranges. The set of
simulations includes various values of the initial Richardson and Reynolds numbers, as well as
Prandtl numbers ranging from 1 to 7. We...
The Columbia Basin once supported a diversity of native fishes and large runs of anadromous salmonids that sustained substantial fisheries and cultural values. Extensive land conversion, watershed disruptions, and subsequent fishery declines have led to one of the most ambitious restoration programs in the world. Progress has been made, but...
The life cycles of three Madden–Julian oscillation (MJO) events were observed over the Indian Ocean as part of the Dynamics of the MJO (DYNAMO) experiment. During November 2011 near 0°, 80°E, the site of the research vessel Roger Revelle, the authors observed intense multiscale interactions within an MJO convective envelope,...
Understanding groundwater conditions in the upland parts of volcanic island aquifers is critical for sustainable groundwater development in these resource-limited environments. Yet groundwater conditions in such settings are generally difficult to characterize because of sparse well drilling (high cost and/or limited access). Information needed for resource evaluation includes upland depth...