Science Meetings

Aquarius SSS-max and SSS-min Views of the Sea
Gordon, A. (11-Nov-14)

For decades oceanographers have had global near synoptic time series views of the sea surface from space, including, in addition to visible images, temperature, height, color, sea ice, wind and marine rainfall patterns, all of which have dramatically expanded our knowledge of the ocean condition, enabling quantitative investigating of ocean processes and their coupling to the atmosphere/climate and marine ecosystems. But only recently have we gathered from orbiting satellites views of the sea surface salinity (SSS), with the advent of ESA's Soil Moisture and Ocean Salinity (November 2009 launch) and of NASA/CONAE Aquarius/SAC-D satellite mission (June 2011 launch). As salinity is a seawater equation-of-state parameter, an active component of ocean dynamics, and an indicator of the marine hydrological cycle, the SSS global near synoptic time series is revolutionizing our understanding of the ocean and earth's climate system. The number of research papers utilizing satellite SSS data is expanding at an ever increasing rate; discoveries are being made and many more will be forthcoming as the SSS time series grows, capturing the interannual and decadal scales of variability. The satellite data reveal river plume patterns within the ocean; detail the ocean response to evaporation/precipitation forcing, e.g. the SSS-max driven by subtropical evaporation, the SSS-min induced by ITCZ downpours, enabling investigation of the ocean processes coupled to such air-sea forcing. The atmospheric and oceanic processes governing SSS are influenced by regional ocean basin configuration, e.g. subtropical SSS-max patterns and locations display marked differences between the 5 subtropical regimes (North and South Atlantic and Pacific; southern Indian Ocean), each is unique in its own way*. The seas of Southeast Asia, from the Bay of Bengal to the South China Sea standout in global SSS maps by their low SSS, owing to excess precipitation and large river outflow. The low SSS water is exported into the surrounding ocean, to balance the net evaporation of the Arabian Sea and into the tropical zone, to interact with the Indonesian throughflow.

*The differences of the 5 subtropics regions are covered in more detail in an article for the SPURS Oceanography issue: "Differences between the Subtropical Surface Salinity Patterns" by A. L. Gordon, C. F. Giulivi, J. Busecke and F. M. Bingham [in revision].