Seasonal Phase Relationships between Sea Surface Salinity, Surface Freshwater Forcing, and Ocean Surface Processes
Year: 2024
Type: article
Abstract: Sea Surface Salinity (SSS) can change as a result of surface freshwater forcing (FWF), or internal ocean processes such as upwelling or advection. At the seasonal scale, SSS should follow FWF by ¼ cycle, or 3 months, if FWF is the primary process controlling it at the seasonal scale. In this paper we compare the phase relationship between SSS and FWF (i.e. evaporation minus precipitation over mixed layer depth) over the global (non-Arctic) ocean using in situ SSS and satellite evaporation and precipitation. We find that instead of the expected 3 month delay between SSS and FWF, the delay is mostly closer to 1-2 months, with SSS peaking too soon relative to FWF. We then compute monthly vertical entrainment and horizontal advection terms of the upper ocean salinity balance equation and add their contributions to the phase of the FWF. The addition of these processes to the seasonal upper ocean salinity balance brings the phase difference between SSS and the forcing processes closer to the expected value. We do a similar computation with the amplitude of the seasonal SSS and the forcing terms, with less definitive results. The results of this study highlight the important role that ocean processes play in the global freshwater cycle at the seasonal scale.
DOI: 10.3390/jmse12091639
Authors: Frederick M Bingham, Susannah Brodnitz
Institution: University of North Carolina Wilmington
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $2,955
Awards: G1361256077, THE WORK PROPOSED HERE WILL ENCOMPASS TWO SEPARATE BUT RELATED ITEMS 1) THE SPATIAL AND TEMPORAL STRUCTURE AND VARIABILITY OF THE TAILS OF THE PROBABILITY DISTRIBUTION OF SEA SURFACE SALINITY (SSS) AND 2) THE IMPORTANCE OF SUBFOOTPRINT VARIABILITY (SFV). THE GOAL OF PART 1 IS AS FOLLOWS: BY EXAMINING THE PROBABILITY DISTRIBUTION OF SSS AND PARTICULARLY THE LOWER AND UPPER TAILS OF THAT DISTRIBUTION WE CAN COME TO BETTER UNDERSTAND THE ALL-IMPORTANT CONNECTION OF SSS TO THE PROCESSES EXTERNAL TO THE OCEAN THAT CONTROL IT AND TO THE GLOBAL WATER CYCLE. IN SHORT WE CAN MOVE TOWARDS THE ORIGINAL GOAL OF THE AQUARIUS PROGRAM TO USE SSS AS AN OCEANIC RAIN GAUGE. THE GOAL OF PART 2 IS: VARIABILITY WITHIN THE FOOTPRINT OF THE AQUARIUS (OR SMAP) SATELLITE HAS NOT BEEN QUANTIFIED IN A SYSTEMATIC ENOUGH WAY. IT MAY OR MAY NOT BE A STRONG CONTRIBUTOR TO MISMATCHES BETWEEN SATELLITE MEASUREMENTS AND IN SITU DATA USED FOR VALIDATION. THIS PROJECT WILL EXPLORE THE IMPORTANCE OF SFV TO SSS VALIDATION.
OpenAlex ID: W4402520058