Fisheries and Oceans Canada

The Atmospheric Forcing Index (AFI) utilizes standardized scores of the first component from a principal components analysis on the Aleutian Low Pressure Index (ALPI), Pacific Interdecadal Oscillation Index, and the northwesterly atmospheric circulation anomalies for the North Pacific (December...

This index measures the relative intensity of the Aleutian Low pressure system of the north Pacific (December through March). It is calculated as the mean area (km²) with sea level pressure <= 100.5 kPa and expressed as an anomaly from the 1950-1997 mean. A positive index value reflects a...

This index is the cumulative summation of negative northwesterly atmospheric circulation frequency anomalies: Z (westerly), M1, (northwesterly), and M2 (southwesterly) for December through March. An increasing trend in Pacific Circulation Index (PCI) reflects increased westerly and southwesterly...