Sea level changes at Port Stanley, Falkland Islands

Time series of sea level change at Port Stanley present a rich spectrum of variability from seiches, tides, and storm surges through to the seasonal, interannual, and secular changes of interest to ocean circulation and climate change studies. This paper emphasizes the strategic importance of the Port Stanley sea level station within a global sea level network through analysis of the decade-length tide gauge records from Port Stanley itself, together with sets of data from a series of temporary tide gauge deployments at several other locations in East Falkland. The characteristics of seiches and of tidal, storm surge, and mean sea level variability are described, and the frequency of extreme sea level events is determined. Port Stanley sea level variability is shown to be "inverse barometer like'' over a wide range of frequencies, although with a significant dependence on the local wind field and an intriguing association with the distant tropical Pacific wind field. Altimeter and tide gauge data in combination demonstrate that the sea level variability is representative of much of the Patagonian shelf and neighboring deep ocean. Consequently, Port Stanley is an ideal site to include within a global network for the purpose of altimeter calibration. The utility of Port Stanley data for monitoring variability in the Falkland-Malvinas Current and Antarctic Circumpolar Current is explored. Port Stanley possesses one of the longest records from a Southern Hemisphere island which indicates an upward sea level secular trend (adjusted for station air pressure) of 0.70 +/- 0.18 ( statistical) +/- 0.25 ( systematic) mm/yr since 1964.