Science Meetings

A Subtropical North Atlantic Regional Atmospheric Moisture Budget
D'Addezio, J.M. and Bingham, F.M. (26-Feb-14)

The subtropical surface salinity maximum region of the North Atlantic Ocean is a complex feature created by air-sea interactions and while the SPURS (Salinity Processes in the Upper Ocean Regional Study) research group has extensively studied how the ocean itself creates this feature, less is known about how the atmosphere above the region is driving it. Atmospheric variables such as evaporation (E), precipitation (P), and moisture flux divergence were evaluated using the reanalysis products MERRA and ERA-Interim. Moisture flux divergence calculations show that the atmosphere is extremely dry which causes freshwater to leave the ocean surface and rise into the atmosphere through evaporation at a mean rate of 4.87 mm/day. Moisture flux divergence has a strong seasonal cycle, with a minimum around October. Moisture flux divergence has similar characteristics as E-P, only with a higher typical value. The mean E-P is 3.50 mm/day. Ekman transport over the high E-P region at 15-20°N is responsible for the northward motion of high salinity waters to the salinity maximum region at 25°N. The balance between Ekman advection and E-P is discussed.