NASA: Aquarius Mission Web Site - Education: Salinity Data & Tools

Education: Salinity Data

+ Salinity Basics + Classroom Activities + Concept Map + Salinity Data & Tools + Posters + Links

Analyzing sea surface salinity data patterns over time provides insight into variations in earth's water cycle. This is because some water cycle processes increase salinity while other processes decrease salinity:

Water Cycle Diagram

Analyzing Monthly Environmental Data

Salinity patterns are governed by geographic differences in the "water budget." For example, like on continents, some areas of the ocean are rainy whereas others are arid and "desert-like." To learn more about the factors that influence salinity patterns, we invite you investigate – with the help of a "Data Analysis Sheet" – five pairs of data maps centered over the North Atlantic Ocean (listed below). Each map shows monthly conditions based on long-term averages. The challenge is to find the data set that most closely corresponds to sea surface salinity patterns.

Air temperature vs. Sea surface salinity
Which type of data exhibits more variation over the year?

Sea surface temperature vs. Sea surface salinity
Does the warmest surface water have the highest salinity?

Evaporation vs. Sea surface salinity
Do the highest evaporation rates occur over waters of the highest salinity?

Precipitation vs. Sea surface salinity
Do the highest precipitation rates occur over waters of the lowest salinity?

Evaporation minus precipitation (E-P) vs. Sea surface salinity
What is the environmental significance of the "0" line on the E-P map?

Would you like the answers for the "Data Analysis Sheet"? Contact Annette deCharon, Senior Science Educator and Aquarius EPO Manager.

For more in-depth analysis, monthly images for all data sets are also available in .pdf format:
Sea surface salinity | Air temperature | Sea surface temperature | Evaporation | Precipitation
Evaporation minus precipitation (E-P)

Spatial Patterns, Annual Cycles, and Changes Over Time

In anticipation of the 2010 launch of Aquarius, our education technology team has developed a set of interactive tools using historical salinity, temperature, and density data sets (NOAA World Ocean Atlas & Database, 2005). These data are available as three distinct yet complementary tools that highlight: (1) spatial patterns of long-term mean data; (2) annual cycle of monthly mean data; and (3) change over time of yearly mean data. Each interactive tool has its own "Tutorial" slide show.

Glossary Words

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

evaporation: The physical process of converting a liquid to a gas. Commonly considered to occur at a temperature below the boiling point of the liquid.

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 salinity is generally in the range from 32 to 37.

precipitation: Water released from the atmosphere in the form of rain, snow, hail, or sleet from the atmosphere onto Earth's surface.

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 practical salinity units (psu).