Resolving the Global Surface Salinity Field and Variations by Blending Satellite and In Situ Observations

Abstract

This Community White Paper (CWP) examines the present Sea Surface Salinity (SSS) observing system, satellite systems to measure SSS and the requirements for satellite calibration and data validation. We provide recommendations for augmenting the in situ observing network to improve the synergism between in situ and remote sensing measurements. The goal is have an integrated (in situ-satellite) salinity observing system to provide necessary the global salinity analyses to open new frontiers of ocean and climate research. It is now well established that SSS is one of the fundamental variables for which sustained global observations are required to improve our knowledge and prediction of the ocean circulation, global water cycle and climate. With the advent of two new satellites, the ocean observing system will begin a new era for measuring and understanding the SSS field. The SMOS (Soil Moisture and Ocean Salinity) and Aquarius/SAC-D (Scientific Application Satellite-D) missions planned to be launched between late 2009 and late 2010, are intended to provide ~150-200 km spatial resolution globally, and accuracy ~0.2 psu, or better, on monthly average. The challenge for the next decade is to combine these satellite and in situ systems to generate the optimal global SSS analysis for climate and ocean research. The in situ data provide surface calibration and validation for the satellite data, while the satellites provide more complete spatial and temporal coverage. The first priority is the maintenance of the existing in situ SSS observing network. In addition, we propose specific enhancements, ideally to include (1) deploying ~ 200 SSS sensors on surface velocity drifters and moorings in key regions, and (2) adding higher vertical resolution near-surface profiles to ~100 Argo buoys to address surface stratification, mixing and skin effects. Plans during the next few years to deploy a significant fraction of these enhanced measurements are identified.

Sea surface freshening inferred from SMOS and ARGO salinity: impact of rain

“…As a consequence, there is a strong need for well sampled SSS time series both for monitoring the changes and for deepening the respective roles of the atmosphere and ocean dynamics and thermodynamics and air-sea interactions on the observed SSS changes. It is expected that the new satellite SSS missions, the Soil Moisture and Ocean Salinity (SMOS) mission and the Aquarius mission, will provide new SSS data sets, complementary to in situ measurements (Lagerloef et al, 2010).…”

Remotely Sensed Winds and Wind Stresses for Marine Forecasting and Ocean Modeling

“…In these regions, NWP products are strongly tied to the radiosonde network, with little agreement in the upper atmosphere between NWP products even one grid cell away from the radiosonde observations [59]. Therefore satellite observations of surface data are essential in the high latitudes.…”

“…In addition, knowledge of the winds and waves over the ocean is also essential for the maritime transportation, fishing, and oil production industries, as well as for search and rescue efforts, and the accurate tracking and management of marine hazards such as oil spills. It is also essential for determining the ocean forcing, wind induced mixing, currents [59], and air/sea CO 2 fluxes.…”

Synthesis and Assimilation Systems - Essential Adjuncts to the Global Ocean Observing System

“…With the advances made with satellite altimetry, Argo and the global tropical moored buoy arrays, and upcoming observations such as the completion of the RAMA array [18], satellite measurements of surface salinity [89], and high resolution ocean surface topography [57], we can be certain that further significant progress will emerge in the coming decade. Some exciting advances, like the contributions being made to observing system evaluation/design, the use of global ocean models at true eddy resolving resolution (1/12° or better) [88], and the developments of assimilation with coupled oceanatmosphere models, are already underway.…”