Temperature and salinity variability on the eastern Newfoundland shelf: The residual field

Open Access
Publisher Website
Google Scholar
Abstract
Time series of temperature, salinity and ice area from the Newfoundland and Labrador Shelves during 1951–86 are examined to determine the temporal and spatial scales of variability outside of the annual band. Significant interannual (periods of 1.8–18 a) variability of temperature (root‐mean‐square amplitude ≈ 0.5°C) and salinity (≈ 0.1) is found at all depths and, for depths greater than about 100 m, is exceeded or matched only by the annual component. Vertical scales of the low‐frequency variability for the depth range 0–75 m are estimated to be twice as large for salinity (60 m) as for temperature (30 m); whereas, for the depth range of 75–175 m, they are the same (90 m) and exceed the scales for the 0–75 m interval. The dominance of low‐frequency energy and the size of the vertical scales at depths ≥ 100 m suggest that the irregular‐temporal and widely spaced vertical sampling of the hydrographic time series would not affect a study of interannual variability in this region. The analysis also suggests that the subsurface low‐frequency variability is correlated over horizontal distances of about 1000 km, though the time series are too short to establish statistical confidence.