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Technology & Operations: Fact Sheet

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Download Aquarius "Project Overview"

Salient Features

L-band Radiometer / Scatterometer
Argentina (CONAE) Provided Spacecraft (SAC-D) & mission operations component
Dedicated Delta II launch vehicle
Launch date: 2010
Sun synchronous polar orbit (98º inclination)
657 km (408 mi) orbit with 6 PM (mean local) nodal crossing time
Two SAC-D instruments will complement Aquarius science measurements: CONAE Microwave Radiometer for wind, rain, cloud water, sea-ice detection; and CONAE New IR Scanner Technology for supplementary sea surface temperature
Operational life: 3 years
Science Partnership with CONAE

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Science

First precise global, space-based observations of Sea Surface Salinity (SSS)

Produce global salinity maps (0.2 psu) on a monthly basis

Chart seasonal and year-to-year variations of SSS

Observe & model the process that relate salinity variations to climate changes in the global cycling of water. Understand how these variations influence ocean circulation

Aquarius will provide an unprecedented view of ocean's role in climate and weather

→ "Geophysical Contributions to Satellite Salinity Measurement" [image, above] Among the important geophysical factors that need to be included in the retrieval of salinity from a sensor in space are emission from the atmosphere, Faraday rotation in Ionosphere, temperature and roughness (waves) of the ocean surface, and the presence of down-welling radiation from the celestial background that is reflected from the surface into the radiometer. The presence of rain and land within the antenna footprint also needs to be taken into account.

Glossary Words

atmosphere: Gaseous layer surrounding a planet; the whole mass of air surrounding the earth.

climate: The prevailing or normal pattern of weather at a place, or in a region, averaged over a long period of time; in contrast to weather, which is the state of the atmosphere at a particular time.

conductivity: A measure of the ability of a material to conduct or transmit an electric charge.

model: System of data, inferences, and relationships, presented as a description of a process or entity.

practical salinity unit (psu): Used to describe the concentration of dissolved salts in water, the UNESCO Practical Salinity Scale of 1978 (PSS78) defines salinity in terms of a conductivity ratio, so it is dimensionless. Salinity was formerly expressed in terms of parts per thousand (ppt) or by weight (parts per thousand or 0/00). That is, a salinity of 35 ppt meant 35 pounds of salt per 1,000 pounds of seawater. Open ocean salinities are generally in the range between 32 and 37.

salinity: A measure of the quantity of dissolved solids in ocean water. In general, salinity reflects the total amount of dissolved solids in ocean water in parts per thousand by weight after all carbonate has been converted to oxide, the bromide and iodide to chloride, and all the organic matter oxidized. Salinity is now measured as pratical salinity units (psu).

system: 1) A regularly interacting or interdependent group of items forming a unified whole. 2) A manner of classifying. 3) A group of interacting bodies under the influence of related forces.

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