An Investigation of Salinity Variability in the Sargasso Sea Using Land Based Meteorological Observations, Radar Precipitation Estimates and an Atmospheric GCM
[26-Feb-2014] Monk, S.A., Johnson, R.J., Bates, N.R., and Risi, C.
Presented at the 2014 Ocean Sciences Meeting
Variations in surface ocean salinity provide evidence of changing patterns in the global hydrological cycle, and the extensive time-series data collected at the Hydrostation S and Bermuda Atlantic Time-series Study (BATS) sites in the North Atlantic Ocean provides an excellent data source for investigating these changes. Since 1954 the upper ocean at Hydrostation S has increased in salinity by 0.002 year-1, indicative of either a change in the local evaporation minus precipitation (EMP) or large-scale advection. Direct comparison between the open ocean surface salinity and land based radar precipitation estimates at Hydrostation S and BATS can be made due to their unique location. Encouragingly, radar estimates of precipitation in Bermuda show good correlation with direct land based measurements. To assess net salinity change, hourly radar data provided by the Bermuda Weather Service, were combined with standard meteorological observations to determine EMP fluxes at Hydrostation S and BATS for 2013. Additionally, the longer-term changes in freshwater fluxes at these time-series sites were compared to model predictions from the Laboratoire de Météorologie Dynamique (LMDZ) atmospheric general circulation model.