Science Meetings

Ocean Eddy Freshwater Flux
Gordon, A.L. and Giulivi, C.F. (17-Apr-13)

Improved in situ and remote sensing observational tools, along with high resolution models, allow us to ask the question (which we have a chance to answer): What role does the ocean mesoscale play in compensating the air-sea flux of heat and freshwater? In situ ocean observations suggest that the answer might be 'substantial', at least in the salty subtropical regimes, where conventional wisdom looks to the Ekman transport driven shallow meridional overturn circulation for compensation of net evaporation. Within the salty North Atlantic subtropics regime the annual evaporation minus precipitation (E-P) is over 1 m/year. While E-P is always positive, greater in January-July, minimum in October, the SSS cycle is out-of-phase, with a maximum in October, minimum occurs in April. It is hypothesized that the lower SSS of the winter/spring period marks increased winter freshwater flux. Using the in situ database as assimilated in the SODA model, we find that the eddy field can accomplish ~50% of the required freshwater compensation. The combination of Aquarius ocean surface salinity with mesoscale sea level from satellite altimeter offers an opportunity for more of complete spatial/temporal evaluation of the role of the mesoscale in compensating for the regional subtropical E-P.