Along North America's West Coast, winter sea level pressure is a top-down driver of coastal upwelling, precipitation, and river discharge. Remarkable coherence among these geophysical parameters induces covariance of biological productivity across marine and terrestrial ecosystems, as evidenced by growth-increment chronologies of fish, clams, and trees. Robust paleoenvironmental records indicate that these biologically-relevant winter climate patterns are dominated by low-frequency, 40-60 year periodicities at higher latitudes.
