Sea-level Variation in Hudson Bay, Canada, from Tide-Gauge Data

Abstract

Sea-level variation in Hudson Bay is examined using tide-gauge data from Churchill, Manitoba. Statistical analysis shows that 43% of the variation in this record is the result of variation in the local Churchill River discharge. Evidence is also found for the delayed effect of advective lag of discharge from James Bay on Churchill sea level. Increase in the seasonal amplitude of sea level after 1975 is the result of anthropogenically induced river diversion. Long-term changes, particularly an increase in the rate of sea-level drop from 1970 to 1985, is not likely the result of changes in local discharge, but is possibly the result of thermal contraction of the world ocean due to short-term cooling from 1960 to 1975. We speculate that changes in atmospheric conditions related to the North Atlantic Oscillation since 1970 may also affect sea-level changes in Hudson Bay.