Following the Water Cycle

The amount of dissolved salt in the ocean is relatively stable. However, the flux of freshwater into and out of the sea is always changing. Salinity patterns help to discern the water cycle over the ocean, where most of the world's evaporation and precipitation occurs.
Water cycle icon

Sea surface salinity is key to understanding how freshwater moves into and out of the ocean system. Using satellite data from Aquarius and SMAP, scientists are now able to relate salinity variations to evaporation and precipitation, providing insight into how the ocean responds to seasonal and annual changes in the water cycle. Use the resources on this page to learn more about how water circulates around the globe.

Raymond Schmitt
An Oceanographer's View of the Water Cycle
movie | MP4 (232.3 MB)
Video cover: Aquarius sea surface salinity tour 2012
Aquarius Sea Surface Salinity Tour 2012
movie | MP4 (94.4 MB)
Susan Lozier
Density Effects
movie | MP4 (5.0 MB)
Video cover: earth's water cycle
Earth's Water Cycle
movie | MP4 (45.7 MB)
Evaporation and precipitation in the western hemisphere
Evaporation and Precipitation in the Western Hemisphere
image
Document cover page: evaporation investigation
Evaporation Investigation
hands-on activity | PDF (1.3 MB)
Graph of evaporation minus precipitation
Evaporation Minus Precipitation 1981-2002
image
Susan Lozier
Geographic Variations in Salinity
movie | MP4 (5.3 MB)
Document cover page: if rain falls on the ocean
If Rain Falls on the Ocean - Does It Make a Sound?
document | PDF (302 KB)
2012 Global ocean surface salinity map
Long Term Composite Image: 01-Jan-12 to 31-Dec-12
image
Susan Lozier
Ocean Overturning and Heat Distribution
movie | MP4 (2.6 MB)
Video cover: ocean currents
Perpetual Ocean
movie | MP4 (81.6 MB)
Cover page: precipitation and the water cycle
Precipitation and the Water Cycle
online interactive
Stephen Riser
Rain At Sea Has Consequences for Global Salinity
movie | MP4 (352.6 MB)
Video cover: salt of the earth part 2
Salt of the Earth: Ocean Atmosphere Circulation Helps Moderate Climate
movie | MP4 (5.0 MB)
Video cover: salt of the earth part 1
Salt of the Earth: Salinity, Temperature & Density
movie | MP4 (7.6 MB)
Raymond Schmitt
The Role of Evaporation and Precipitation
movie | MP4 (75.7 MB)
Video cover page: the water cycle
The Water Cycle
movie | MP4 (21.3 MB)
Document cover: the water cycle
The Water Cycle - Now You See It, Now You Don’t
hands-on activity | PDF (1.5 MB)
Video cover: thermohaline circulation -tThe great ocean conveyor belt
Thermohaline Circulation - The Great Ocean Conveyor Belt
movie | MP4 (6.1 MB)
Video cover: thermohaline circulation using improved flow field
Thermohaline Circulation Using Improved Flow Field
movie | MP4 (22.7 MB)
Water cycle diagram
Water Cycle Diagram
image
Water cycle effects on ocean salinity
Water Cycle Effects on Ocean Salinity
image
Water cycle poster
Water Cycle Poster for Kids
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Video cover: water, water everywhere
Water, Water Everywhere: Condensation & Precipitation
movie | MP4 (5.4 MB)
Eric Lindstrom
What are Ocean Deserts?
movie | MP4 (309.2 MB)
Diagram of earth's water
Where is Earth’s Water?
image

FAQs

There's no such thing as absolute good or bad, right? In certain areas, you want to monitor the change, that's really the key. You want to see whether the area's freshwater gets fresher, you know, and if the salty water gets saltier. That represents the speeding up or slowing down of the water cycle. So you ask the questions: do we have more evaporation as we change the climate? Do we have more freshwater melting? All these questions are related.

Mostly due to the land-sea contrast (located between two major continents). It is also smaller than the Pacific.

There are quite a lot of interesting discoveries the science community has been finding from the Aquarius data over the ocean. The dynamics involving fresh water from precipitation and how it mixes with upper layers of the ocean is of special interest. Satellites measure salinity at the surface. We also use ocean buoys, but readings use conductivity sensors to measure salinity at a depth of about five meters, a depth at which algae is less likely to grow. We know that the surface layer, aerated by wave motion and carrying warm water in the tropics, is conducive to algae growth. Sensors placed closer to the surface would become fouled with algae and no longer function. At a depth of five meters, algae growth is discouraged, the increased salinity at depth acts much the same as chlorine would in a swimming pool. The ever-changing salinity dynamic in the top five meters of the oceans has recently become a topic of great interest to oceanographers and climate scientists. Its understanding is now seen as a key factor in predicting weather patterns and changing climate.