Volume transport and modes of variations of the Malvinas Current at 44.7°S from satellite altimetry and current-meter velocities
Event: 2019 Ocean Surface Topography Science Team Meeting
Session: Science II: Large Scale Ocean Circulation Variability and Change
Presentation type: Type Oral
The southern portion of the Malvinas Current (MC) circulation is exanimated using satellite altimetry data and in-situ velocity time series gathered at three mooring sites (from March 2015 to May 2017) along the Patagonian Shelf break at 44.7°S. The in-situ data provided the first opportunity to compare altimetry-derived velocities with high temporal resolution near-surface current meter velocities in this tract of MC. Globally, altimetry-derived velocities correlate rather well (r>0.8) with the in-situ velocities at 300 m depth both in strength and direction. The quality of the altimetric surface geostrophic velocities being assessed, altimetry was used to further interpret the observations at the isolated mooring sites and to put them in context of the 24-year-long altimetric time series. Leading modes and temporal scales of variability were analyzed. During the in-situ measurement period, the spatial structure of the two-dominant modes of Mean Sea Level Anomaly that explain more than 50% of the variance were associated to the presence a westward meander of high ADT close to 44.7° S, which affect the MC flow beyond that latitude. The 24-year-long altimetry time series revealed that these patterns are robust. Moreover, we combined altimetric and the in-situ data to compute a volume transport time series of the MC at 44.7°S. The variability of the transport time series is analyzed and compared with estimates obtained of further north in previous studies.