Large–scale Ocean and Atmospheric Indicators

Local and Regional Physical Indicators

Local Biological Indicators

Indicators Under Development

Introduction to Pacific Northwest Oceanography

Ocean Sampling Methods

Glossary^*

Aleutian Low
A semi–permanent, subpolar area of low pressure located in the Gulf of Alaska near the Aleutian Islands.  It is a generating area for storms, and migratory lows often reach maximum instensity in this area.  It is most active during the late fall to late spring.  During the summer, it is weaker, retreating toward the North Pole and becoming almost nonexistent.   During this time, the North Pacific High pressure system dominates (NOAA National Weather Service).  Courtesy of NOAA National Weather Service. 

CPUE
Catch per unit effort (CPUE) is a relative and indirect measure of fishing effectiveness or species abundance.  "Catch" can mean weight of a total catch, weight of a particular species caught, or numbers of total fish or particular species. "Units of effort" can be defined as individual cruises, number of sets of a fishing net (or casts of a line), or a measure of time or distance.  Here we define CPUE as the number of a particular species caught per number of kilometers traveled with the trawl under tow.

Geostrophic Wind
A wind that is affected by coriolis force, blows parallel to isobars and whose strength is related to the pressure gradient (i.e., spacing of the isobars).  Courtesy of NOAA National Weather Service. 

Jack
A "Jack" is a male Chinook or coho salmon that returns to spawn prematurely, before growing to the size of a normal adult.  Jacks stay in the ocean from a few months to a year, returning to the natal stream 1–2 years before normal adults of their age class.  Thus numbers of returning jacks are sometimes used as a basis to predict run size the following year. 

Oblique Tow
An oblique tow is made by pulling the net at a slow tow speed from the sea floor to the surface.  Under this configuration, the angle between the net and sea floor is maintained at 45 degrees. 

OPIH
Oregon Production Index, Hatchery

Secchi Disk
A device to measure the turbidity (transparency) of the upper water column.  A 30–cm diameter white disc is lowered slowly through the upper water column to the point at which the pattern is no longer visible.  The depth of the disk is then taken as a measure of transparency or turbidity. 

Teleconnection
The term "teleconnection pattern" refers to a recurring and persistent, large–scale pattern of pressure and circulation anomalies that spans vast geographical areas. Teleconnection patterns are also referred to as preferred modes of low–frequency (or long time–scale) variability.  Courtesy of the NOAA National Weather Service Climate Prediction Center. 

Transmissometer
A device for measuring beam attenuation, which can be used as a measure of turbidity in water.  A beam of light is cast through the water and the transmissometer records the measure of light at a given point past the source of the beam.