Bermuda’s tale of two time series : Hydrostation S and BATS

• Published in: Journal of Physical Oceanography
• Main Authors: Phillips, Helen E., Joyce, Terrence M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Meteorological Society 2007
• Subjects: Ocean variability; Climate variability; Seasonal cycle; Labrador Sea
• Online Access: https://hdl.handle.net/1912/4140

Author Posting. © American Meteorological Society, 2007. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 37 (2007): 554–571, doi:10.1175/JPO2997.1. This paper describes the oceanic variability at Bermuda between 1989 and 1999, recorded in two overlapping hydrographic time series. Station S and Bermuda Atlantic Time Series Study (BATS), which are 60 km apart, both show that a multidecadal trend of deep warming has reversed, likely as a result of the increased production of Labrador Sea Water since the early 1980s. In addition to recording similar changes in watermass properties, the two time series show similar mean vertical structure and variance as a function of pressure for temperature, salinity, and density above 1500 dbar. The seasonal cycles of these water properties at the two sites are statistically indistinguishable. The time series differ in the individual eddy events they record and in their variability below 1500 dbar. The two time series are used to investigate the propagation of eddy features. Coherence and phase calculated from the low-mode variability of density show westward propagation at 3 cm s−1 of wavelengths around 300–500 km. Satellite altimeter data are used to provide a broader spatial view of the eddy (or wave) field near Bermuda. We acknowledge support from NSF Grant OCE-0219644, the Australian Greenhouse Office, and CSIRO.