Recent shifts in the state of the North Pacific

The winters of 1999–2002 for the North Pacific were characterized by spatial patterns in sea level pressure anomaly (SLPA) and sea surface temperature anomaly (SSTA) with little resemblance to those of the leading pattern of North Pacific climate variability, the Pacific Decadal Oscillation (PDO). In essence, the southeastern (northern) portion of the North Pacific was subject to atmospheric forcing characteristic of that before (after) the major regime shift of 1976–77. Recent major changes in the ecosystems off the west coast of the United States and continued conditions similar to those of the early 1990s in the Gulf of Alaska, Bering Sea, and Sea of Okhotsk are consistent with these SLPA and SSTA patterns. Our result illustrates that a single indicator such as the PDO is incomplete in characterizing North Pacific climate.