SISS Working Group Abstracts

SISS Working Group

Satellite & In Situ Salinity (SISS) Working Group: Current Status and Future Plans
Contact author: Yi Chao, <ychao@remotesensingsolutions.com>
All Authors:
Yi Chao, Remote Sensing Solutions
Jacqueline Boutin, LOCEAN-I PSL

The Aquarius and SMOS salinity satellite missions have established the Satellite & In Situ Salinity (SISS) Working Group (WG). The major goal of this WG is to improve our understanding of the link between L-band satellite (SMOS and Aquarius) remotely sensed salinity (for approximately the top 1 cm of the sea surface) and in situ measured salinity (routinely measured at a few meters depths by ships and ARGO floats but recently accessible to up to few cm depth by new profilers, and by surface drifters) and to develop practical methodologies for relating satellite salinity to other estimates of sea surface salinity. The SISS WG has established a mailing list and organized several community workshops at major conferences (e.g., AGU, EGU). The first WG effort to develop a schematic diagram of upper ocean salinity stratification will be presented. Plans to host another workshop at the upcoming AGU Fall meeting in San Francisco and develop a community white paper will be discussed.

Mixed layer salt balance and the role of eddies in a global ocean simulation
Contact author: James Carton, <Carton@atmos.umd.edu>
All Authors:
James Carton, University of Maryland
Semyon Grodsky, University of Maryland
Benjamin Johnson, University of Maryland
Frank Bryan, NCAR

Here we examine the detailed salt balance of the mixed layer in a 0.1 degree resolution multi-decadal simulation of the global ocean/ice system forced by observed historical surface fluxes (1979-2010), with the flux calculations carried out on the original grid every time step. Initial conditions were provided by a simulation forced by Normal Year forcing. The simulation is generally realistic with a slight negative bias in salinity. Here we focus on a comparison of the salt balance as it varies with latitude from the rainy tropics through the dry subtropics and into the humid midlatitudes. To separate the contribution of eddies to the salt balance from those associated with the seasonal cycle we define the eddy flux contribution, e.g. , to be associated with timescales of two months or less.
The results show a complex set of balances that vary with latitude and timescale. One striking result is that the net surface salt flux does not dominate the salt balance. Horizontal advection and vertical diffusion of salt across the base of the mixed layer are generally large as well. The contribution of eddy transports is smaller than recently reported and generally not a dominant term, although eddies may be dominant in certain regions. We include comparison of the balances in the dry SPURS1 and rainy SPURS2 regions as well as a discussion of the changes associated with the phase of ENSO.

The Diurnal Cycle of Salinity
Contact author: Kyla Drushka, <kdrushka@apl.uw.edu>
All Authors:
Kyla Drushka, University of Washington Applied Physics Laboratory
Sarah Gille, Scripps Institution of Oceanography
Janet Sprintall, Scripps Institution of Oceanography

TAO mooring data are used to estimate the diurnal cycle of salinity in the tropics and to assess the drivers of diurnal salinity. A comparison against the Aquarius ascending and descending salinity observations reveals that the ascending/descending bias version 3.0 of Aquarius is generally an order of magnitude larger than the diurnal cycle in salinity at 1-m depth. A 1-d turbulence model is used to explore the relative roles of rain and wind in generating diurnal salinity variations.