Sea level variations in eastern Canadian waterbodies

Abstract

Sea level records from nine stations in eastern Canada have been analyzed in order to investigate the seasonal trends and other long‐term changes that have occurred since the beginning of this century. The four stations situated in riverine or estuarine regions are significantly affected by freshwater flow in their annual cycle of sea level changes and exhibit a definite maximum in spring and minimum in autumnwinter. Other stations situated in the eastern half of the Gulf of St. Lawrence or near the open Atlantic coast follow the general cycle of subarctic regions, with a low in spring‐summer and a high in autumn‐winter. Such seasonal variations appear to be related to the atmospheric pressure and baroclinic current variations. Secular trends in mean sea level show a mean rise of about 25.6 cm/century along the Atlantic coast of Canada. The monthly mean sea level series are subjected to Fourier spectral analysis in an attempt to identify the major long‐period cycles present in the records. The spectrum displays a major peak corresponding to the yearly cycle. In addition, evidence is found at different stations for the nodal tide (18.6 years), the sunspot cycle (10.8 years), the lunar perigee (8.47 years), and the pole tide (14.5 months).

Keywords:

• sea‐level
• seasonal variations
• nodal tide
• sunspot cycle
• lunar perigee
• pole tide
• Gulf of St. Lawrence
• Atlantic coast
• Canada