Dynamic topography (ERS-1/2 and seatruth) of subtropical ring (STORM 0) in the storm corridor (32-34°N, eastern basin, north Atlantic ocean)

Hydrographic measurements were made on RRS 'Charles Darwin' Cruise CD97 of the structure of a Subtropical Ring called STORM discovered south-west of the Azores in October 1995 which moved westward along a latitude near 32.5 degrees N. The results showed an elliptical ring structure with a ratio of minor to major axis of 0.6. The external Ring structure extended across a scale of similar to 400 km in an east-west direction along the major axis of the structure. The internal structure showed isotherms (isopycnals) that were domed upwards by similar to 200 m. The swirl transport in the Ring was 44 Sv with a negligible barotropic component and the cyclonic flow extended throughout the water column from the surface (maximum similar to 50 cm s(-1), at a radial distance of similar to 100 km) with reduced intensity to the sea-floor similar to 4km depth where the flow was effectively zero. The surface currents and dynamic height data showed that the STORM centre was associated with a similar to 38cm lowering of sea level. The ERS-1 and ERS-2 altimeter surface signature of STORM revealed a similar structure (similar to 42cm sea level depression) but with a larger scale of influence similar to 500 km. The remote sensing surface elevation structure derived from altimetry also maps (similar to-600X) changes in the deeper ocean temperature structure and transport (1 cm change equivalent similar to 1 Sv) in the general region. A similar to 500 d record from a current meter mooring deployed in the region showed three STORM signatures, each separated by a mean of similar to 180 days. in June 1996, HMS 'Hecla' crossed the North Atlantic at a latitude near 33 degrees N and found three STORM temperature signatures. The mean spacing between STORMs was estimated as similar to 540km. STORMs, separated by 540km, move westward at 3 km d(-1) along a latitude near 33 degrees N in the Eastern Basin of the North Atlantic.