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Grade levels: 5-8, 9-12
Theme: water cycle
Tool: http://aquarius.nasa.gov/education-datatools.html

Analyzing sea surface salinity data patterns over time provides insight into variations in the earth's water cycle. This is because some water cycle processes increase salinity while other processes decrease salinity (see map at right).

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 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.

Grade level 5-8: Look at monthly maps of: air temperature vs. sea surface salinity and precipitation vs. sea surface salinity. Are any of these data sets closely correlated with solar energy input (e.g., seasonal change)?

Grade level 9-12: For the North Atlantic Ocean, look at monthly maps of air temperature vs. sea surface salinity and precipitation vs. sea surface salinity and evaporation vs. sea surface salinity. Are changes in these data sets closely correlated with solar energy input (e.g., seasonal change) in the North Atlantic ocean? Look at these videos -- Sea Surface Salinity and Components of the Water Cycle for global data sets of sea surface temperature, precipitation, and evaporation.

Grade levels: K-4, 5-8, 9-12
Themes: 21st century technology, ocean circulation, water cycle
Flat Tool: http://ourocean.jpl.nasa.gov/AQUARIUS/chp2.jsp
GoogleEarth Interface Tool: http://aquarius.jpl.nasa.gov/AQUARIUS_DEV/chp2.jsp

Create global maps of mean conditions for any month at designated depths (down to 1500m) using the pull-down menus. Monthly time-series graphs of salinity, temperature, or density can be plotted by selecting up to six locations (by clicking on the map or typing latitude/latitude information into the fields below). These time-series graphs can also represent up to six different depths. Plotted data will also be shown in a table that is easily downloaded (e.g., into Excel). Sources include interpolated atlas data or actual measurements from the database.

Focus Questions | Flat Tool Tutorial

Grade level: 9-12
Theme: 21st century technology
Video: aquarius_passive_satellilte.flv

One thing to note about the Aquarius satellite is that it's what we call a "passive" satellite. Even though it takes a lot of work to get up there and a lot of people are working to put it up there, what it's doing is actually recording the wavelengths that the earth is radiating. So some satellites are "active": so they are sending a signal down through the atmosphere to earth's surface and then they are recording that signal that comes back. But when we're trying to measure the sea surface salinity, the Aquarius satellite will be recording the microwaves that the earth is sending back out to the atmosphere and space.

Grade level: 9-12
Theme: 21st century technology
Video: argo07_640x480.flv

ARGO is a global array of 3,000 free-drifting profiling floats that measures the temperature and salinity of the upper 2,000 meters (6,562 feet) of the ocean. This allows continuous monitoring of the temperature, salinity, and velocity of the upper ocean, with all data being relayed and made publicly available within hours after collection. ARGO measurements will be a key component calibrating - or "sea truthing" - the surface salinity measurements of Aquarius. An overview article from Oceanography magazine, "Salinity in ARGO", by Stephen Riser, Li Ren, and Annie Wong is available as a PDF.

This visualization shows the locations of the ARGO buoy array over time. When the buoys are above water, the lines are brighter; when the buoys are under water, the lines are fainter. The ARGO buoys measure ocean salinity, column temperature, and current velocities. (source)

Grade level: 9-12
Theme: ocean circulation
Video: elnino-320.flv

Water vapor is a small but significant constituent of the atmosphere, warming the planet due to the greenhouse effect and condensing to form clouds which both warm and cool the Earth in different circumstances. A key feature of global atmospheric water vapor convection is the Intertropical Convergence Zone, the low pressure region within five degrees of the equator where the trade winds converge and solar heating of the atmosphere forces water-laden air to rise in altitude, form clouds, and then precipitate as rain in the afternoon.

	Legend for the water vapor animation, showing separate colorbars for total precipitable water and precipitation.

This visualization shows the global water vapor distribution in gray and white and the global precipitation in yellow every hour from December 20, 1997 to January 14, 1998. The afternoon thunderstorms in the tropics are seen as a flashing yellow region that moves from east to west, following the sun. This is an El Niño period, when the water to the west of South America is warmer than normal, allowing the atmosphere there to heat up and hold more water. This region feeds a high band of water vapor reaching to the southeastern United States and causes increased humidity and rainfall in that region.

These data are from the Goddard Earth Modeling System, a coupled land-ocean-atmosphere model which uses earth and satellite-based observations to simulate the Earth's physical system during events such as El Niño. (source)

Compare this video with Components of the Water Cycle: Flow of Atmospheric Water Vapor.

Grade levels: 5-8, 9-12
Themes: 21st century technology, climate, water cycle
Flat Tool: http://ourocean.jpl.nasa.gov/AQUARIUS/chp3.jsp
GoogleEarth Interface Tool: http://aquarius.jpl.nasa.gov/AQUARIUS_DEV/chp3.jsp

Create global maps of mean conditions for any year(s) from 1800 to 2005 at designated depths (down to 1500m) using the pull-down menus. Annual time-series graphs of salinity, temperature, or density can be plotted by selecting up to six locations (by clicking on the map or typing latitude/latitude information into the fields below). These time-series graphs can also represent up to six different depths. Plotted data will also be shown in a table that is easily downloaded (e.g., into Excel). Source is actual, non-interpolated database measurements.

Focus Questions | Flat Tool Tutorial

Grade level: 9-12
Theme: water cycle
Video: global_ocean_04.flv

Soon a new satellite will even help us see tiny particles on the ocean's surface - like salt, which drives huge conveyor belts of water through the world's oceans, connecting currents and moving heat from pole to pole. Climate change could mean big changes for oceans. And that in turn would make life very different for those of us on dry land.

Paula Bontempi: "If the climate actually changes, and the oceans change or respond to that change, it most definitely will impact life as we know it, and especially humans."

David Adamec: "To understand exactly how we stay here and how we're going to survive both within the climate, and even our life cycle, it requires understanding what the water is doing."

Our climate is changing... in some places, faster than predicted. By using science to understand those changes, we can find ways of protecting our oceans - and ourselves - that make a world of difference.

Grade level: 9-12
Theme: water cycle
Video: global_ocean_03.flv

Other kinds of satellite sensors look at the Earth in a far different light. Heat sensing satellite instruments take the Earth's temperature by measuring infrared energy. Infrared wavelengths are invisible to our eyes, but some satellites can see them. And, as our climate changes, we can see ocean temperatures on the rise.

Other satellites show us peaks and valleys, not just on land - but, believe it or not - on the surface of the ocean. And as ice on land melts, there are increasingly more highs than lows. Sea level is rising.

Grade levels: K-4, 9-12
Theme: 21st century technology
Video: global_ocean_01.flv

The Earth's climate is changing... in some places, faster than predicted. Something - or someone - is cranking up the heat. And many scientists say the main culprit is us. Climate change affects almost everything on our planet - including people. But could climate change affect something as huge, as deep, as mysterious as our oceans? Earth scientists are determined to find out.

Paula Bontempi: "You can see the atmosphere, you can see the land, but you can't really see beneath the ocean's surface. So you start wondering, you know, what's going on beneath the part we can see."

David Adamec: "We walk in a very small part of the atmosphere, and we walk on the land. And it's how that interaction takes place with the ocean, the atmosphere, and the land that determines our quality of life. Our goal is to understand the interconnectedness of it all."

For years, people have worked to unravel the mysteries of the oceans. Scientists gather data from ships and buoys on the surface, take the plunge to explore ocean depths, and fly overhead to get a bigger picture. But one of the best views of oceans might be from way, way overhead. It's the view from space.

Paula Bontempi: "The one thing that NASA satellites do that nothing else does, ships or buoys or anything else, is actually give you a picture of the globe within a few days. You get a much broader view of what's going on in some part of the Earth's system, and you can link that together to understand the Earth as a whole."

Grade level: 9-12
Theme: 21st century technology
Video: global_ocean_02.flv

Thousands of satellites orbit our planet. Some look out into space. Others look back at us... at Earth. Some of the sensors on these satellites act like giant digital cameras, taking pictures in visible light - the kind our eyes see. On land, these images show us when plants turn green, with the changing seasons. They help us see where dirt and pollution drain into the sea, and where microscopic plankton thrive. These tiny organisms are not only the base of the marine food web... they give us the air we breathe.

David Adamec: "We are dependent on life in the water. Especially in the ocean. There are small plants called phytoplankton that are responsible for 50 percent of the oxygen that you're breathing right now."

Grade levels: 5-8, 9-12
Themes: climate, ocean circulation
Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf

Activity 4.3: Convection (p. 36-37). A good grasp of the underlying principles of thermal physics is essential for understanding how the ocean functions and how it impacts climate. Thermal physics is one of the science subjects that students are familiar with and experience on a daily basis, but intertwined with the experiential knowledge they bring to class comes a mixed bag of misconceptions that must be identified and addressed. Example misconceptions include an inability to differentiate between heat and temperature, the notion that transfer of heat will always result in a temperature rise, and a misunderstanding of the concept of latent heat.

The purpose of this activity is to review basic concepts of thermal physics and highlight applications to ocean processes by focusing on the concept of convection. Convection and advection are the major modes of heat transfer in the ocean and atmosphere. Convection occurs only in fluids and involves vertical motion of fluid, or flow, rather than interactions at the molecular level. It results from differences in densities - hence buoyancy - of fluids. Examples of convective processes include: currents in Earth's mantle, which drive the tectonic system and result from heating and cooling of magma; atmospheric circulation resulting from uneven solar heating (e.g., between the poles and the equator); the global ocean conveyor belt and formation of deep water masses, resulting from cooling of surface water at high latitudes; and vertical mixing in the ocean's upper layer due to variations in heating between day and night. Advection usually refers to horizontal transfer of heat with the flow of water (e.g., the Gulf Stream).

Read the following sections of Chapter 4 (Heat and Temperature) in preparation for this activity:

  •  Background (p. 32)
  •  Mechanisms of Heat Transfer (p. 33)

Flash Video | QuickTime Movie

Grade level: 9-12
Theme: water cycle
Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf

Activity 1.6: Convection Under Ice (p. 10). In oceanography, density is used to characterize and follow water masses as a means to study ocean circulation. Many processes are caused by or reflect differences in the densities of adjacent water masses or differences in densities between fluids and solids. Plate tectonics and ocean basin formation, deep-water formation and thermohaline circulation, and carbon transport by particles sinking from surface waters to depth are a few examples of density-driven processes. This activity is designed to highlight links to oceanic processes.

In the left panel in the photo at right, an ice block floats in tap water because the density of ice is lower than that of freshwater. As the ice melts, however, cold, colored meltwater sinks to the bottom because it is denser than the tap water. Warmer water from the bottom is then displaced and upwells, resulting in a convective flow visible in the dye patterns. Ice melting in the center of the tank is analogous to a convection "chimney" formed in the open ocean, while ice melting at the tank's edge is analogous to a chimney on a continental shelf (near a land mass). Such chimneys in the ocean, created and sustained by convective processes, appear as "columns" of mixed water that flow downwards. For a given set of oceanic and meteorological conditions, open-water convection tends to entrain (mix with) more of the surrounding waters than does convection near a land mass. The open-ocean case therefore results in downwelled water that is less dense.

In the right panel, the ice block floats in dense, salty water. As the ice melts, only a small amount of dye sinks because the density of the saltwater is greater than the density of the newly melted, fresh, ice-cold water. Most of the meltwater accumulates in a surface layer on top of the denser salt layer.

Read the Background section (p. 4-5) of Chapter 1 (Density) in preparation for this activity.

Note: Even though this experiment focuses on temperature only, it can be used to discuss how salinity, like temperature, affects the density of ocean water.

Grade levels: 5-8, 9-12
Theme: ocean circulation
Video: density_effects.flv

I think most everybody can understand that if there is light fluid on top of heavy fluid then we have what's called a "stable system". Because things that are heavier are perfectly "happy" to be underneath something that's light. And what we say is that there is something that's less dense on top of something that's more dense.

But in the ocean it often happens that the reverse happens: so we might get something that's heavy, heavier (like) more dense waters on top of lighter water. And when that happens, we say that the ocean is unstable and we have "overturning". That means that the waters that are heavy come down to the bottom part of the ocean and those that are light need to go up. And that happens when waters are cooled and it also happens when the upper waters get saltier because of evaporation, etc.

So those density differences mean that the ocean is going to circulate: it's going to move. And those density differences can come about because of temperature changes or salinity changes.

Grade level: 9-12
Theme: 21st century technology

Design your own experiment based on the activities conducted for the following outcomes:

1. Explain the relationship between fresh water and ocean dynamics.
2. Determine if global precipitation, evaporation, and the cycling of water are changing.
3. Explain the influence of the El Niño Southern Oscillation on global weather patterns.
4. Explain the influence of ocean salinity on the thermohaline circulation (e.g., "global conveyor belt").
5. Describe how changes in the ocean's circulation can produce large changes in climate.
6. Explain how climate variations can induce changes in the global ocean circulation.

Use the online tools where applicable.

Grade level: 9-12
Theme: water cycle
Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf

Activity 1.5: Effect of Stratification on Mixing (p. 9-10). In open ocean regions (with the exception of polar seas), the water column is generally characterized by three distinct layers: an upper mixed layer (a layer of warm, less-dense water with temperature constant as a function of depth), the thermocline (a region in which the temperature decreases and density increases rapidly with increasing depth), and a deep zone of dense, colder water in which density increases slowly with depth.

Mixing of stratified layers requires work. Without energetic mixing (e.g., due to wind or breaking waves), the exchanges of gases and nutrients between surface and deep layers will occur by molecular diffusion and local stirring by organisms, which are slow, ineffective modes of transfer. The energy needed for mixing is, at a minimum, the difference in potential energy between the mixed and stratified fluids. Therefore, the more stratified the water column, the higher the energy needed for vertical mixing.

Density is fundamentally important to large-scale ocean circulation. An increase in the density of surface water, through a decrease in temperature (cooling) or an increase in salinity (ice formation and evaporation), results in gravitational instability (i.e., dense water overlying less-dense water) and sinking of surface waters to depth. Once a sinking water mass reaches a depth at which its density matches the ambient density, the mass flows horizontally, along "surfaces" of equal density. This process of dense-water formation and subsequent sinking is the driver of thermohaline circulation in the ocean. It is observed in low latitudes (e.g., the Gulf of Aqaba in the Red Sea, the Gulf of Lions in the Mediterranean Sea) as well as in high latitudes (e.g., deep water formation in the North Atlantic).

This experiment looks at the energy required to mix two layers. Students should read the Background section (p. 4-5) of Chapter 1 (Density) in preparation for this activity.

Flash Video | QuickTime Movie

Grade levels: 5-8, 9-12
Theme: ocean circulation
Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf

Activity 1.4: Effects of Temperature & Salinity on Density & Stratification (Steps 1- 4; p. 8). Stratification refers to the arrangement of water masses in layers according to their densities. Water density increases with depth, but not at a constant rate. In open ocean regions (with the exception of polar seas), the water column is generally characterized by three distinct layers: an upper mixed layer (a layer of warm, less-dense water with temperature constant as a function of depth), the thermocline (a region in which the temperature decreases and density increases rapidly with increasing depth), and a deep zone of dense, colder water in which density increases slowly with depth.

Stratification forms an effective barrier for the exchange of nutrients and dissolved gases between the top, illuminated surface layer where phytoplankton can thrive, and the deep, nutrientrich waters. Stratification therefore has important implications for biological and biogeochemical processes in the ocean. For example, periods of increased ocean stratification have been associated with decreases in surface phytoplankton biomass. In coastal waters, prolonged periods of stratification can lead to hypoxia (low oxygen), causing mortality of fish, crabs, and other marine organisms.

This activity compares salt and fresh water, demonstrating that fluids arrange into layers according to their densities. Students in grades 9-12 should read the Background section (p. 4-5) of Chapter 1 (Density) in preparation for this activity.

Flash Video | QuickTime Movie

Grade levels: 5-8, 9-12
Theme: ocean circulation
Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf

Activity 1.4: Effects of Temperature & Salinity on Density & Stratification (Steps 5-7; p. 9). Stratification refers to the arrangement of water masses in layers according to their densities. Water density increases with depth, but not at a constant rate. In open ocean regions (with the exception of polar seas), the water column is generally characterized by three distinct layers: an upper mixed layer (a layer of warm, less-dense water with temperature constant as a function of depth), the thermocline (a region in which the temperature decreases and density increases rapidly with increasing depth), and a deep zone of dense, colder water in which density increases slowly with depth.

Stratification forms an effective barrier for the exchange of nutrients and dissolved gases between the top, illuminated surface layer where phytoplankton can thrive, and the deep, nutrientrich waters. Stratification therefore has important implications for biological and biogeochemical processes in the ocean. For example, periods of increased ocean stratification have been associated with decreases in surface phytoplankton biomass. In coastal waters, prolonged periods of stratification can lead to hypoxia (low oxygen), causing mortality of fish, crabs, and other marine organisms.

This activity compares warm and cold water, demonstrating that fluids arrange into layers according to their densities. Students in grades 9-12 should read the Background section (p. 4-5) of Chapter 1 (Density) in preparation for this activity.

Flash Video | QuickTime Movie

Grade level: 9-12
Theme: ocean circulation
Article: documents/21.1_yashayaev.pdf

The Labrador Sea is the coldest and freshest basin of the North Atlantic. Winter cooling in this sea produces Labrador Sea Water. This intermediate water plays an important role in the exchange of heat, freshwater, and other substances between the atmosphere and the abyssal ocean, affecting the water masses, circulation, and, ultimately, climate of the subpolar North Atlantic basins.

The subpolar gyre of the North Atlantic has exhibited large changes in temperature, salinity, and volume over the past six decades, largely in response to changing winter conditions over the Labrador Sea. The signature of these changes can be seen in the lower limb of the Meridional Overturning Circulation down into the North Atlantic tropics.

Read and discuss the Abstract and Introduction (p. 30-32).

Grade level: 9-12
Theme: 21st century technology
Video: aquarius_launch.flv

Aquarius is going to be launched later this year. And one of the great things about it is that it has been in planning for a number of years and the launch is very exciting to all of those of us who have been working on it and looking forward to the launch. The main thing about it is that it is going to be giving us more data. So anybody who works in studying the oceans, the atmosphere, or the land on large scales is always interested in getting back more data. Because that just tells us a lot more about how the earth is working.

Grade level: 9-12
Theme: climate
Activity: http://www.pbs.org/newshour/extra/teachers/lessonplans/science/jan-june08/polar_oceanography.html

Part II: Exploring Global Ocean Currents. We know that conditions experienced in the Arctic and Antarctic are quite different from those experienced where most people live. This activity allows students to look for connections between these two diverse regions located thousands of kilometers apart through the conduct of experiments designed to explore the connections between three major Earth systems: the atmosphere, the hydrosphere and the cryosphere.

Part III: Ocean Currents and Coastal Climates. Do ocean currents affect coastal climates? Resources provided with this activity enable students to access climatic data for two communities: St. Mawgan, England, and Daniels Harbour, Newfoundland, Canada. Both communities are located near 50°N latitude. St. Mawgan is situated on the southwestern coast of England along the eastern shores of the Atlantic Ocean. Daniels Harbour is located in Newfoundland near the western shores of the Atlantic Ocean. Students will collect, process, and analyze climate data to answer questions on temperature patterns, prevailing winds, and the Gulf Stream.

Grade level: 9-12
Theme: 21st century technology
Video: getting_full_picture.flv

Up until now when we've been trying to understand how density changes impact ocean circulation, we've really just had half the picture. Because we've just be able to look at our global coverage of temperature.

But with the Aquarius mission, we'll be able to complete that other half. We'll be able to look at the salinity information; and the salinity combined with temperature will give us the information about the density field.

Grade level: 9-12
Theme: 21st century technology
Video: how_aquarius_works.flv

Most of us understand that the sun emits energy. We are very aware of that and we recognize the differences between day and night. But the earth also emits energy. In fact, everything that has a temperature emits energy. But the earth emits energy at different frequencies and different wavelengths than the sun. And when the earth emits that energy back, it emits most of that energy in what's called the infrared spectrum.

But some of that energy comes back at wavelengths that are micro-wavelengths. And the microwave lengths - the amount of energy that's emitted by the ocean - depends on the salinity. It is related to something we call the "brightness temperature". It all has to do with how much energy is emitted from the ocean back to the atmosphere, back out to space. And so if a satellite is sitting there, it's actually recording how much energy in that microwave segment is being emitted. And by the signal that it receives, it's able to "back out" (i.e., calculate) what the ocean salinity is.

Grade level: 9-12
Theme: climate
Article: documents/v39n2-schmitt_2174.pdf

As with similar questions about a tree in the forest or a grain of sand on the beach, it may be hard to imagine that a few inches of rain matters to the deep ocean. After all, the ocean's average depth is around 4 kilometers and only 1 to 5 centimeters of water are held in the atmosphere at any one time. But it does matter, in part because the ocean is salty. The effect of rain diluting the salts in the ocean (or evaporation concentrating them) can be greater than the effect of heating (or cooling) on the density of seawater.

Grade level: 9-12
Themes: climate, water cycle
Video: keeping_up_carbon_03.flv

At the most basic level, the balance between incoming sunlight and outgoing heat determines Earth's climate. Greenhouse gases act like a blanket, and trap heat in the atmosphere. Carbon dioxide is a greenhouse gas. In the past two centuries, humans have increased atmospheric carbon dioxide by more than 30%, by burning fossil-fuels and cutting down forests. The Earth has not experienced carbon dioxide levels this high for the past several million years.

Researchers are learning that future climate change will depend on carbon levels in the land, in the atmosphere, and in the sea, and how these levels respond to human disturbance. About one-third of all human-generated carbon emissions has dissolved into the ocean. More than 80% of Earth's added heat is now stored in the ocean.

Scott Doney: "In the future, as the planet gets warmer, the water's going to warm up, and warm water can hold less carbon than cold water - the other thing is, on a warmer planet, some of the currents are going to slow down, so we might not be forming as much of this cold deep water. So we won't be able to transport carbon into the deep sea. So on the whole, the ocean's going to become less effective at removing carbon from the atmosphere." (source)

Grade level: 9-12
Themes: climate, water cycle
Video: keeping_up_carbon_04.flv

Throughout most of Earth's ocean, the warmer water, weaker circulation, and new temperature gradients that result from climate change will impact marine life and ecosystems. These changes affect the ocean's ability to store carbon. Increased carbon dioxide in the atmosphere impacts marine life in other ways.

Stacey Boland: "As the ocean absorbs more carbon dioxide, it becomes more acidic, and this can be a threat to some of the organisms that live inside the ocean."

As Earth's climate continues to change, how will researchers monitor something as big as the ocean, and something as complex as the carbon cycle? NASA Earth observing satellites give scientists the "big picture" view of our home planet. Varied satellites help researchers detect changes in ocean climate and ecology over time, providing vital insight into the health of our home planet. (source)

Grade level: 9-12
Theme: climate
Video: keeping_up_carbon_01.flv

Carbon is the basic building block of life, and these unique atoms are found everywhere on Earth. Carbon makes up Earth's plants and animals, and carbon is also stored in the ocean, the atmosphere, and the crust of the planet. A carbon atom could spend millions of years moving through Earth in a complex cycle.

Understanding the carbon cycle - and how it is changing - is key to understanding Earth's changing climate. On land, plants remove carbon from the atmosphere through photosynthesis. Animals eat plants and either breathe out the carbon, or it moves up the food chain. When plants and animals die and decay, they transfer carbon back to the soil. Moving offshore, the ocean holds huge amounts of carbon - about 50 times the amount we find in the atmosphere.

Stacey Boland: "The ocean is sometimes called a carbon sink, meaning that it absorbs, or takes up carbon from the atmosphere. It takes up carbon through physical and biological processes." (source)

Grade level: 9-12
Theme: climate
Video: keeping_up_carbon_02.flv

At the ocean's surface, carbon dioxide from the atmosphere dissolves into the water. Tiny marine plants called phytoplankton use this carbon dioxide for photosynthesis. Phytoplankton are the base of the marine food web. After animals eat the plants, they breathe out the carbon or pass it up the food chain. Sometimes phytoplankton die, decompose, and are recycled in the surface waters. Phytoplankton can also sink to the bottom of the ocean, where they become buried in marine sediment.

Over long time scales, this process has made the ocean floor the largest reservoir of carbon on the planet. Most of the ocean's nutrients are in cold, deep water. In a process called upwelling, currents bring nutrients and carbon up to the surface. Carbon can then be released as a gas back into the atmosphere, continuing the carbon cycle. By cycling huge amounts of carbon, the ocean helps regulate climate.

Scott Doney: "So when you think of climate, you don't often think of the ocean. With climate - you think of, is it going to be hotter this year, or is it going to be colder this year? But the oceans are actually a great regulator, a controller of Earth's climate. And they even are controlling how much carbon is in the atmosphere, which can slow down how quickly climate change is occurring." (source)

Grade level: 9-12
Themes: climate, ocean circulation, water cycle
Video: melting_ice_03.flv

Two thirds of the fresh water on Earth is frozen in the world's ice fields. If that ice melts, seas will rise. If all of that ice were to melt, sea level would rise worldwide by 70 meters. No one expects all of that ice to melt anytime soon, but even the meter of sea level rise that many scientists predict for the next century could have dramatic consequences.

Lora Koenig: "Even though the polar regions seem very far from a lot of people's day to day life, they are very important. Because they are regions that cool our earth. And as they change, they're going to cause larger changes throughout the rest of the globe." (source)

Grade level: 9-12
Themes: climate, ocean circulation, water cycle
Video: melting_ice_02.flv

It's important to understand how the world's ice sheets form, how they change over time, and how fast they are moving into the sea. That's where researchers like NASA's Lora Koenig come in. She recently spent three months in Greenland studying the composition of those ice sheets. All ice sheets and glaciers start as snowfall. Those tiny flakes get compressed by the weight of more snow above, and eventually become dense masses of ice.

Lora Koenig: "What we're seeing right now on the ice sheets and glaciers is that they are shrinking in size. And as glaciers on land are shrinking overall, that contributes a little bit to sea level rise. And we are worried that as we see warming over the ice sheets, and increased melting over the ice sheets, that they are going to start contributing much more to sea level rise." (source)

Grade level: 9-12
Themes: climate, ocean circulation, water cycle
Video: melting_ice_04.flv

Josh Willis: "A lot of people live in coastal areas. Coastal places that have beaches. As sea level rises, then beaches begin to erode and we begin to lose wetlands. A lot of different ecologically-sensitive regions lie along the coastline, and as sea level rises, these get flooded (and) the ecosystems, of course, change. And so all of this can have big consequences for people and especially people who live near the coast."

Josh Willis: "As the great ice sheets in Antarctica and Greenland begin to melt and break up due to global warming, we really might experience very rapid sea level rise; three or four times as fast as the rate that we see today. So predicting this rate out into the future is very tricky because we really don't know when the ice sheets might break up and how fast they will when they do. So predicting future sea level rise is one of the great scientific problems of the future." (source)

Grade level: 9-12
Themes: climate, ocean circulation, water cycle
Video: melting_ice_01.flv

The ice is melting. The seas are rising. Little by little, in most parts of the world, the ocean is overtaking the land. Most of us don't think much about sea level rise, but it's one of the biggest signs that humans are affecting the Earth's climate. And it's something worth watching. So the big question is, are we facing a doom and gloom scenario?

Josh Willis: "I prefer not to think about climate change and global warming in terms of doom and gloom scenarios, so much as a change in our planet. Our planet's definitely changing, and we're definitely causing it. So we're going to have learn to deal with some of these changes. But in addition, we're going to have to learn how to make a slightly smaller footprint on our planet."

Josh Willis: "Sea level is rising effectively because of global warming. As the planet heats up, two things happen to the ocean. One is that the temperature of the water increases. And as that happens, the water actually expands and takes up more room. The other thing that happens is that ice that was on land in the form of glaciers and ice sheets begins to melt and as that runs off into the ocean, it increases the water in the ocean, and it actually raises sea level as well. (source)

Grade level: 9-12
Theme: climate
Activity: http://mynasadata.larc.nasa.gov/preview_lesson.php?&passid=9

The purpose of this activity is to discover the link between ocean temperatures and currents as related to our concern for current climate change.

After completing this activity, students will:

	•	Know how differential heating of Earth results in circulation patterns in the atmosphere and oceans that globally distribute the heat.
	•	Know the relationship between the rotation of Earth and the circular motions of ocean currents and air in pressure centers.
	•	Make predictions by linking current scientific satellite data to concerns about global climate change.

Grade level: 9-12
Theme: ocean circulation
Tool: http://mynasadata.larc.nasa.gov/preview_lesson.php?&passid=68

While we inhabit land on the Earth we sometimes forget that we live on a planet where 70 percent of the Earth is covered with water. The variation in the properties of the land versus the water contributes to our global circulation patterns. Sometimes these global circulation patterns are disrupted and we observe the effects of these disruptions in events such as El Niño and La Niña.

It is believed that El Niños occur every two to eight years, and are sometimes stronger, sometimes weaker. This often happens when the southeast trade winds weaken or even reverse. As a result, large masses of water from the western Pacific Ocean migrate to the east to the coast of South America. This change in ocean circulation not only impacts the weather and climate in South America, but also affects locations all around the globe.

These effects can last for about a year, when the opposite conditions occur as the trade winds strengthen again, and the waters off the coast of South America are colder than normal from active upwelling occurring along the coast. This phase of the global circulation disruption is called La Niña.

We have been fortunate over the last 30 years to have satellite and buoy data to warn us if the El Niño phase is upon us. By measuring sea surface heights with satellites like TOPEX Poseidon, sea surface temperature with satellites like AVHRR, and wind vectors from buoys and satellites, we can monitor the Pacific Ocean for changes that may signal the onset of El Niño or La Niña. The sensitive altimeter on the TOPEX Poseidon satellite can measure small changes that create hills and valleys on the sea surface which is mostly caused by thermal expansion (steric effect), and the warming of the ocean during an El Niño event can be sensed by the altimeter.

This lesson explores El Niño by looking at sea surface temperature, sea surface height, and wind vectors in order to seek out any correlations there may be among these three variables. It employs group work where different teams work together to analyze a single variable, and then get together in different groups to compare all three variables. The lesson will guide students through data representing the strong El Niño from 1997 to 1998. By doing this, students will model the methods of researchers who bring their expertise to study integrated science questions. Depending on the classroom dynamics, available technology, and available time, this lesson may be modified.

Grade levels: 5-8, 9-12
Themes: climate, ocean circulation
Tool: http://oceanmotion.org/html/resources/oscar.htm

This data visualizer gives access to the following global ocean surface current behaviors between 1992 and 2008: current speed, current direction, current convergence, and current vorticity as well as the anomaly values for each.

Grade level: 9-12
Theme: ocean circulation
Article: http://www.nasa.gov/centers/goddard/news/topstory/2003/0114salt.html

NASA-sponsored scientists have discovered that by knowing the salt content of the ocean's surface, they may be able to improve the ability to predict El Niño events. Scientists, studying the western Pacific Ocean, find regional changes in the saltiness of surface ocean water correspond to changes in upper ocean heat content in the months preceding an El Niño event. Knowing the distribution of surface salinity may help predict these events.

This study, conducted for NASA by University of Maryland researchers Joaquim Ballabrera, Tony Busalacchi, and Ragu Murtugudde, is one of the first to look at ocean salinity in El Niño, Southern Oscillation (ENSO) predictions and their relationship to tropical sea surface temperatures, sea level, winds, and fresh water from rain.

Grade level: 9-12
Theme: 21st century technology
Video: aquarius_catch_up.flv

A lot of what the Aquarius mission will help us oceanographers do is "catch up" with the atmospheric scientists. One of the big differences between oceanography and atmospheric sciences is that the atmosphere has been so much more sampled than the ocean. So, we know that we've had weather balloons for decades and decades that have told us about the atmospheric winds and atmospheric conditions. And we've measured the atmosphere so much that now we can actually predict the atmospheric currents which means that we can predict things like the weather.

But with the ocean, the ocean has been much more inaccessible. It has been inaccessible because it's very far away from where people live, it's very deep, and it's also it's very salty which means it has been a very corrosive environment for instruments. But what we're able to do now with satellite measurements is get a lot of data over large areas of space and continuously in time. And that information about the salinity, coupled with the information we have about the ocean temperatures because of the NASA satellites, really helps us learn a lot more about the ocean, and the ocean circulation. So one day we will also be able to make predictions about ocean circulation.

Grade level: 9-12
Theme: water cycle
Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf

Activity 4.8: Reversing Rods (p. 40-41). Most substances expand when heated and contract when cooled. As the temperature of most substances increases, their molecules vibrate faster and move farther apart, occupying a larger space. When these substances are cooled, their molecules vibrate slower and remain closer to each other. Note that freshwater below 4°C actually expands when cooled, a phenomena known as the anomaly of water.

Thermal expansion is the principle by which a liquid thermometer works. In the ocean, thermal expansion is thought to contribute significantly to sea level rise on decadal-to-century-long time scales. However, thermal effects appear to be influenced by decadal climate-related fluctuations, making it difficult to estimate the long-term contribution of thermal expansion to sea level rise. Current estimates suggest that thermal expansion is responsible for 25 percent to 50 perccent of observed sea level rise.

In this activity, we look at thermal expansion using two rods, one made of aluminum and the other made of PVC. When placed in cold water, both rods initially float because their densities are lower than that of the cold water. Over time, the PVC rod gets colder and contracts, which results in a density change. When the density of the rod exceeds that of the water, the PVC sinks. The aluminum rod gets colder too, but aluminum expands and contracts much less than PVC when its temperature is changed by the same amount; therefore, the aluminum rod's density is less affected by the temperature change, and it remains floating. Students will also try this experiment with hot water.

Flash Video | QuickTime Movie

Grade level: 9-12
Theme: water cycle
Article: documents/21.1_schmitt.pdf

Articles in this salinity-themed Oceanography issue articulate the potential of our rapidly expanding ability to measure salinity to enhance understanding of the global water cycle.

Read and discuss the first three sections (p. 12-15) of this article.

Grade level: 9-12
Theme: water cycle
Video: salt_of_earth_04.flv

People have been measuring salinity for centuries, but ships and buoys alone cannot match the perspective from space. In fact, a whole quarter of the oceans have no salinity data at all.

Susan Lozier: "Up until now when we've been trying to understand how density changes impact ocean circulation, we've really just had half the picture."

When the Aquarius / SAC-D satellite is launched, scientists can look at salinity of the surface of the ocean from 400 miles above the earth.

Susan Lozier: "But now with the Aquarius mission, we'll be able to complete that other half. We'll be able to look at the salinity information. And so salinity, combined with temperature, will give us the information about the density field."

The satellite will gather more salinity data than in the last 125 years. This mission will help scientists better understand how salinity and ocean circulation are tied to global climate and how both systems are changing throughout time. (source)

Grade levels: 5-8, 9-12
Themes: climate, ocean circulation, water cycle
Video: salt_of_earth_03.flv

The oceans are vast, covering 70 percent of our planet, and so it is no surprise that we still know only a little about this system, and how it will respond to change, and furthermore, create change.

Jeff Halverson: "Climate change on earth is complicated by the fact that the ocean moves much more slowly than the atmosphere. So you have warming in the atmosphere, warming in the ocean, but they're occurring at different speeds. So they're out of sync, and that makes predicting what's going to happen in the next hundred or two years very, very difficult."

Susan Lozier: "Now what we might expect happens, in a very simplistic sense, is that as the ocean warms, there's going to be more evaporation. And that more evaporation would would mean that oceans become saltier. But really it's not just that simple because there's also evaporation, precipitation, and the ice as well, and that's all wrapped up in the study of the hydrologic cycle." (source)

Grade levels: 5-8, 9-12
Themes: climate, ocean circulation, water cycle
Video: salt_of_earth_02.flv

Susan Lozier: "And the atmosphere and the ocean, both being fluids of the earth, really work together. We consider them sort of equal partners in the redistribution of this heat on the planet. So when those warm waters are returning, as they're moving up to the higher and higher latitudes then, they're releasing that heat to the atmosphere. Then the winds blow over the ocean, they pick up that heat and those winds over the Atlantic Ocean are moving from the North American continent to the European continent."

Jeff Halverson: "It takes perhaps a thousand years for the water to cycle through the deep ocean. So we say the oceans have a memory. They're like a tape recorder. Things that happen now will still be manifest hundreds of years in the future as that cold water moves through this giant circulation."

Susan Lozier: "So if there's any change to that overturning circulation, that means that Northern Europe and the British Isles would be robbed of that heat due to those waters that are returning to the high latitudes." (source)

Grade levels: 5-8, 9-12
Themes: ocean circulation, water cycle
Video: salt_of_earth_01.flv

Susan Lozier: "And it seems a little odd in a way because salt is really a molecule in the ocean water, but collectively, that salinity plays a role in the ocean circulation."

It's these differences in salinity that play a role in the processes that affect weather, climate, sea life, and the whole ocean system itself. And not all oceans have the same salinity. In fact, the North Atlantic Ocean tends to be the saltiest, much more than the Pacific.

Susan Lozier: "The salt in the ocean affects its density, just like the temperature affects its density, and the density, meaning the amount mass per volume, is going to then impact where the water goes as it circulates throughout the globe."

Jeff Halverson: "Differences in temperature and salt content of the water cause some areas of water to sink and some areas of water to rise. And so we tend to see the sinking water at the poles, the water rising back up at the equator, and if you connect the two together, what you have is an overturning that is deep in the ocean. It's like a big conveyor belt that operates in the ocean."

This overturning moves warm water from the tropics toward the poles, and cold water from the poles toward the tropics. In this way the overturning regulates earth's climate. (source)

Grade levels: 5-8, 9-12
Themes: ocean circulation, water cycle
Video: density_reverse_direction.flv

The average density of sea surface water can be calculated from the average sea surface temperature and salinity using the state equation for seawater. This animation shows the long term average sea surface density, with light blue regions having the least density and dark blue regions having the greatest density. The sea surface density variations are actually very small, less than 3 percent overall, but the variation is very important.

There are three stable, dense regions in the ocean's surface, one in the sea around Iceland, Greenland, and Scandinavia and the other two near or under major Antarctic ice shelves. In these regions, the surface water becomes dense enough to sink and join the deep ocean currents. In fact, this sinking is thought to drive these deep currents as part of a system called the Thermohaline Circulation. This circulation has a strong effect on the Earth's climate, influencing the Gulf Stream, El Niño events, and both past and future climate shifts. (source)

Grade level: 9-12
Theme: ocean circulation
Video: sss_reverse_direction.flv

The heat of the sun forces evaporation at the ocean's surface, which puts water vapor into the atmosphere but leaves minerals and salts behind, keeping the ocean salty. The salinity of the ocean also varies from place to place, because evaporation varies based on the sea surface temperature and wind, rivers and rain storms inject fresh water into the ocean, and melting or freezing sea ice affects the salinity of polar waters.

This animation shows the long term average sea surface salinity, where white regions have the highest salinity and dark regions the lowest. Notice the higher salinity in the Atlantic, due partly to salty water coming from the Mediterranean, and the lower salinity at the mouths of major rivers. (source)

Grade level: 9-12
Theme: water cycle
Video: Aerosol_Sources_Full_Seq_640x360.flv

Aerosols are complex particles; they occur in nature and can also be generated by human activity. One important new area of aerosol research involves how aerosols impact clouds. Without aerosols, clouds could not exist. Aerosol particles serve as condensation nuclei for water vapor in the atmosphere. Atmospheric water molecules are drawn to aerosol particles like magnets, forming water droplets and eventually creating a cloud. The introduction of a larger number of aerosols will modify cloud's natural properties, leading to an accumulation of water droplets that are smaller in size but greater in number. Clouds play an important role in regulating Earth's climate; aerosol-rich air masses generate clouds that are bigger, brighter, and longer lasting.

Aerosols can occur in nature, but they can also originate from human activity. This animation provides an introduction to four of the varied sources of atmospheric aerosols: cities, forest fires, the ocean, and deserts. This animation shows the different sources of aerosols, how they mix in the Earths atmosphere, and finally disappear by creating sediment or raining out.

Of particular interest is the role of the oceans: salts from the sea spray serve as condensation nuclei. In this animation, sea salt spray aerosols rise into the sky, follows the path downwards to the source (the ocean), and back up into the sky where the aerosols gather in a cloud. (source)

Grade levels: 5-8, 9-12
Themes: 21st century technology, climate, ocean circulation, water cycle
Flat Tool: http://ourocean.jpl.nasa.gov/AQUARIUS/chp1.jsp
GoogleEarth Interface Tool: http://aquarius.jpl.nasa.gov/AQUARIUS_DEV/chp1.jsp

Interactive maps of surface conditions can be clicked to create in-water profiles of salinity, temperature, or density. Sources include interpolated atlas data or actual measurements from the database.

Focus Questions | Flat Tool Tutorial

Grade level: 9-12
Theme: 21st century technology
Article: documents/21.1_lagerloef.pdf

In an Oceanography article published 13 years ago, three of us identified salinity measurement from satellites as the next ocean remote-sensing challenge. We argued that this represented the next "zeroth order" contribution to oceanography because salinity variations form part of the interaction between ocean circulation and the global water cycle, which in turn affects the ocean's capacity to store and transport heat and regulate Earth's climate.

Now, we are pleased to report that a new satellite program scheduled for launch in the near future will provide data to reveal how the ocean responds to the combined effects of evaporation, precipitation, ice melt, and river runoff on seasonal and interannual time scales. These measurements can be used, for example, to close the marine hydrologic budget, constrain coupled climate models, monitor mode water formation, investigate the upper-ocean response to precipitation variability in the tropical convergence zones, and provide early detection of low-salinity intrusions in the subpolar Atlantic and Southern oceans.

Read and discuss the text on the Aquarius/SAC-D mission design (p. 73-74).

Grade level: 9-12
Theme: climate
Video: CarbonCycleFinal_ipod.m4v.flv

Carbon is the basic building block of life, and these unique atoms are found everywhere on Earth. Carbon makes up Earth's plants and animals, and is also stored in the ocean, the atmosphere, and the crust of the planet. A carbon atom could spend millions of years moving through Earth in a complex cycle. This conceptual animation provides an illustration of the various parts of the carbon cycle. Purple arrows indicate the uptake of carbon; yellow arrows indicate the release of carbon.

On land, plants remove carbon from the atmosphere through photosynthesis. Animals eat plants and either breath out the carbon, or it moves up the food chain. When plants and animals die and decay, they transfer carbon back to the soil. Moving offshore, the ocean takes up carbon through physical and biological processes. At the ocean's surface, carbon dioxide from the atmosphere dissolves into the water. Tiny marine plants called phytoplankton use this carbon dioxide for photosynthesis. Phytoplankton are the base of the marine food web. After animals eat the plants, they breathe out the carbon or pass it up the food chain. Sometimes phytoplankton die, decompose, and are recycled in the surface waters. Phytoplankton can also sink to the bottom of the ocean, where they become buried in marine sediment. Over long time scales, this process has made the ocean floor the largest reservoir of carbon on the planet. In a process called upwelling, currents bring cold water containing carbon up to the surface. As the water warms, the carbon is then be released as a gas back into the atmosphere, continuing the carbon cycle.

Carbon is found in the atmosphere as carbon dioxide, which is a greenhouse gas. Greenhouse gases act like a blanket, and trap heat in the atmosphere. In the past two centuries, humans have increased atmospheric carbon dioxide by more than 30 percent, by burning fossil-fuels and cutting down forests. (source)

Grade levels: K-4, 5-8, 9-12
Themes: ocean circulation, water cycle
Video: water_cycle_ipod_640x480.m4v.flv

This animation shows one molecule of water completing the hydrologic cycle. Heat from the sun causes the molecule to evaporate from the ocean's surface. Once it evaporates, it is transported high in the atmosphere and condenses to form clouds.

Clouds can move great distances and eventually the water molecule will fall as rain or snow. Ultimately, the water molecule arrives back where it started...at the ocean. (source)

Grade levels: 5-8, 9-12
Theme: ocean circulation
Video: thermohaline_conveyor_iPod.m4v.flv

Surface ocean currents are driven mostly by the wind. In certain areas near the polar oceans, the colder surface water also gets saltier due to evaporation or sea ice formation. In these regions, the surface water becomes dense enough to sink to the ocean depths. This pumping of surface water into the deep ocean forces the deep water to move horizontally until it can find an area on the world where it can rise back to the surface and close the current loop. This usually occurs in the equatorial ocean, mostly in the Pacific and Indian Oceans. This very large, slow current is called the thermohaline circulation because it is caused by temperature and salinity ("haline") variations.

This animation shows one of the major regions where this pumping occurs: the North Atlantic Ocean around Greenland, Iceland, and the North Sea. The surface ocean current brings new water to this region from the South Atlantic via the Gulf Stream and the water returns to the South Atlantic via the North Atlantic Deep Water current. The continual influx of warm water into the North Atlantic polar ocean keeps the regions around Iceland and southern Greenland mostly free of sea ice year round. The animation also shows another feature of the global ocean circulation: the Antarctic Circumpolar Current. The region around latitude 60 degrees south is the the only part of the Earth where the ocean can flow all the way around the world with no land in the way. As a result, both the surface and deep waters flow from west to east around Antarctica. This circumpolar motion links the world's oceans and allows the deep water circulation from the Atlantic to rise in the Indian and Pacific Oceans and the surface circulation to close with the northward flow in the Atlantic. (source)

Grade levels: 5-8, 9-12
Theme: ocean circulation
Video: thermohaline_rev.flv

The oceans are mostly composed of warm salty water near the surface over cold, less salty water in the ocean depths. These two regions don't mix except in certain special areas. The ocean currents, the movement of the ocean in the surface layer, are driven primarily by the wind. In certain areas near the polar oceans, the colder surface water also gets saltier due to evaporation or sea ice formation. In these regions, the surface water becomes dense enough to sink to the ocean depths. This pumping of surface water into the deep ocean forces the deep water to move horizontally until it can find an area on the world where it can rise back to the surface and close the current loop. This usually occurs in the equatorial ocean, mostly in the Pacific and Indian Oceans. This very large, slow current is called the thermohaline circulation because it is caused by temperature and salinity (haline) variations. This animation shows one of the major regions where this pumping occurs, the North Atlantic Ocean around Greenland, Iceland, and the North Sea. The surface ocean current brings new water to this region from the South Atlantic via the Gulf Stream and the water returns to the South Atlantic via the North Atlantic Deep Water current. The continual influx of warm water into the North Atlantic polar ocean keeps the regions around Iceland and southern Greenland generally free of sea ice year round.

The animation also shows another feature of the global ocean circulation: the Antarctic Circumpolar Current. The region around latitude 60 south is the only part of the Earth where the ocean can flow all the way around the world with no obstruction by land. As a result, both the surface and deep waters flow from west to east around Antarctica. This circumpolar motion links the world's oceans and allows the deep water circulation from the Atlantic to rise in the Indian and Pacific Oceans, thereby closing the surface circulation with the northward flow in the Atlantic.

The color on the world's ocean's at the beginning of this animation represents surface water density, with dark regions being most dense and light regions being least dense (see the animation Sea Surface Temperature, Salinity and Density). The depths of the oceans are highly exaggerated (100x in oceans, 20x on land) to better illustrate the differences between the surface flows and deep water flows. The actual flows in this model are based on current theories of the thermohaline circulation rather than actual data. The thermohaline circulation is a very slow moving current that can be difficult to distinguish from general ocean circulation. Therefore, it is difficult to measure or simulate.

This version of the visualization combines the Earth look of the original thermohaline visualization with the new thermohaline flow field generated for the Science on a Sphere production, "Loop". (source)

Grade level: 9-12
Theme: ocean circulation
Activity: documents/vtop_oc_variations_el_nino.pdf

An El Niño is thought to be triggered when steady westward blowing trade winds weaken and even reverse direction in the western Pacific Ocean, near New Guinea and Australia. This change in the winds allows the large mass of warm water that is normally located in the western Pacific to move eastward along the equator until it reaches the coast of South America. This displaced pool of unusually warm water affects evaporation and where rain clouds form, altering the typical atmospheric jet stream patterns around the world. Scientists are studying information from satellites and in-water buoys to better understand the causes and effects of an El Niño.

In this activity, students will analyze satellite images of sea surface temperature, sea surface topography, and wind data from an El Niño period and compare and contrast these data with non-El Niño conditions.

Grade levels: K-4, 9-12
Themes: ocean circulation, water cycle
Video: water_everywhere_02.flv

Paula Bontempi: "The water evaporates and goes into the atmosphere, and then it doesn't necessarily just turn around and fall as rain or snow."

Condensation is the process by which water vapor molecules cool, stick together, and become liquid again in cloud formation. This often happens high in the atmosphere where the temperature is much lower than it is near the surface.

Paula Bontempi: "What happens in the atmosphere is, just like we have currents in the ocean, we have winds in the atmosphere that actually, to some extent, drive what goes on in the ocean currents. Materials in the atmosphere can travel a great distance, sometimes a quarter of a way around the world, just until they get to the point where they actually turn into rain or snow and thereby fall back to the ocean or fall back to the land. This is called precipitation. If the water molecule falls on the land as snow, it may be stored for a very long period of time in a polar ice sheet or mountain glacier, depending on climate conditions."

Matt Rodell: "When rain falls or the snow melts, typically the next place it goes, it infiltrates the soil. So soil is not solid. It's not like a rock, there are pore spaces that can be filled with water and typically there is a certain amount of water in the soil at all times. If soil was completely dry, plants wouldn't be able to grow." (source)

Grade levels: K-4, 9-12
Themes: ocean circulation, water cycle
Video: WC_precipitation_IPOD.m4v.flv

This animation displays the intensity of precipitation as it flows around the globe, showing heavy precipitation in orange/yellow and light precipitation in purple. This video is a clip taken from Water, Water Everywhere which incorporates audio not included in this clip.

Water regulates climate, storing heat during the day and releasing it at night. Water in the ocean and atmosphere carry heat from the tropics to the poles. The process by which water moves around the earth, from the ocean, to the atmosphere, to the land and back to the ocean is called the water cycle.

This animation was created using data from the GEOS-5 atmospheric model on the cubed-sphere, run at 14-km global resolution for 30-days. Variables animated here include evaporation, water vapor and precipitation. This animation is time synchronous throughout the animation to allow cross fades during compositing. (source)

Grade level: 9-12
Theme: water cycle
Video: water_everywhere_03.flv

If soil becomes saturated, any additional rainfall will collect in puddles and streams. Soil water that percolates deep enough will help to recharge an aquifer.

Matt Rodell: "An aquifer is any underground geologic formation that stores water so it's typically either rock with a lot of cracks in it, or it's (a) sandy layer. Sand has a lot of pore space in it and can store a lot of water."

A water molecule might remain in an aquifer for more than a million years. More likely, it would help to replenish a stream, which would feed into lakes and rivers. Eventually, the water molecule will return to where it started: the ocean.

People also have a role in the water cycle. By pumping water out of the ground for irrigation, cutting down forests for development and building roads and other concrete surfaces that lead to runoff, people can have a serious impact on the path a water molecule takes.

Matt Rodell: "The most obvious way that people affect the water cycle are the ways that we control the water after it's fallen on the land surface as rain or melts as snow... But we have put in dams and rivers to hold this water. We've also pumped the groundwater out and used that. So it's these water resources, as we call them, are really us taking a natural part of the water cycle and using it to our benefit."

Grade levels: K-4, 5-8, 9-12
Themes: ocean circulation, water cycle
Video: water_everywhere_01.flv

Water is all around us, and its importance to nearly every process on earth cannot be underestimated. It is the only compound that can be found naturally as a liquid, gas, and solid. The process by which water moves around the Earth, from the ocean to the atmosphere to the land, and back to the ocean, is called the water cycle. Water regulates climate, storing heat during the day and releasing it at night, and carries heat from the tropics to the poles, by sea and by air.

Let's follow a single molecule of water, beginning in the ocean, through the paths it might take before eventually winding up right where it started - back in the big blue sea. The fuel for this journey will be provided by our planet's prime energy source: the sun. During the day, the sun heats up the air and ocean surface, causing water molecules to evaporate. Evaporation occurs when a liquid molecule of water escapes into the air as a gas.

This scientific visualization shows how water evaporation, indicated in turquoise, is driven by the energy of the sun. Notice how the rate of evaporation pulses over land: it speeds up during the day and almost disappears at night. Over the ocean, evaporation appears to remain constant, both day and night. Water in the air in gas form is known as water vapor. The molecule is now fresh water, having left the ocean salt and other particles behind. (source)

Grade levels: K-4, 5-8, 9-12
Themes: ocean circulation, water cycle
Video: Evap_and_clock_IPOD.m4v.flv

This animation of evaporation shows how heating from the sun causes increased evaporation over land during the day. This video is a clip taken from Water, Water Everywhere which incorporates audio not included in this clip.

Water regulates climate, storing heat during the day and releasing it at night. Water in the ocean and atmosphere carry heat from the tropics to the poles. The process by which water moves around the earth, from the ocean, to the atmosphere, to the land and back to the ocean is called the water cycle.

This animation was created using data from the GEOS-5 atmospheric model on the cubed-sphere, run at 14-km global resolution for 30-days. Variables animated here include evaporation, water vapor and precipitation. This animation is time synchronous throughout the animation to allow cross fades during compositing. (source)

Grade levels: K-4, 5-8, 9-12
Themes: ocean circulation, water cycle
Video: WC_evaporation_IPOD.m4v.flv

This animation of evaporation shows how heating from the sun causes increased evaporation over land during the day. This video is a clip taken from Water, Water Everywhere which incorporates audio not included in this clip.

Water regulates climate, storing heat during the day and releasing it at night. Water in the ocean and atmosphere carry heat from the tropics to the poles. The process by which water moves around the earth, from the ocean, to the atmosphere, to the land and back to the ocean is called the water cycle.

This animation was created using data from the GEOS-5 atmospheric model on the cubed-sphere, run at 14-km global resolution for 30-days. Variables animated here include evaporation, water vapor and precipitation. This animation is time synchronous throughout the animation to allow cross fades during compositing. (source)

Grade levels: K-4, 5-8, 9-12
Themes: ocean circulation, water cycle
Video: WC_vapor_IPOD.m4v.flv

This animation portrays the flow of atmospheric water vapor around the world. This video is a clip taken from Water, Water Everywhere which incorporates audio not included in this clip.

Water regulates climate, storing heat during the day and releasing it at night. Water in the ocean and atmosphere carry heat from the tropics to the poles. The process by which water moves around the earth, from the ocean, to the atmosphere, to the land and back to the ocean is called the water cycle.

This animation was created using data from the GEOS-5 atmospheric model on the cubed-sphere, run at 14-km global resolution for 30-days. Variables animated here include evaporation, water vapor and precipitation. This animation is time synchronous throughout the animation to allow cross fades during compositing. (source)

Grade levels: K-4, 5-8, 9-12
Themes: ocean circulation, water cycle
Video: WC_SST_IPOD.m4v.flv

This animation of sea surface temperature shows the transport of heat along the ocean's surface. This video is a clip taken from Water, Water Everywhere which incorporates audio not included in this clip.

Water regulates climate, storing heat during the day and releasing it at night. Water in the ocean and atmosphere carry heat from the tropics to the poles. The process by which water moves around the earth, from the ocean, to the atmosphere, to the land and back to the ocean is called the water cycle.

Data for this animation was derived from a model run of ECCO's Ocean General Circulation Model of heat along the ocean's surface. (source)

Grade levels: K-4, 5-8, 9-12
Themes: ocean circulation, water cycle
Video: WC_rivers_IPOD.m4v.flv

In this animation, pulsing of the global rivers highlights the flow of water from the continents back into the oceans. This video is a clip taken from Water, Water Everywhere which incorporates audio not included in this clip.

Water regulates climate, storing heat during the day and releasing it at night. Water in the ocean and atmosphere carry heat from the tropics to the poles. The process by which water moves around the earth, from the ocean, to the atmosphere, to the land and back to the ocean is called the water cycle. (source)

Grade level: 9-12
Theme: water cycle
Video: water_everywhere_04.flv

The water cycle affects and is affected by climate variations.

Matt Rodell: "The water cycle is one of the ways that we will really feel any changes in climate. So climate changes will feed back to water cycle changes, things like how much precipitation an area receives, the frequency of droughts and floods and this sort of thing."

The water cycle is the adventurous journey that water takes through the oceans, atmosphere, and land, driven by the sun. Improving our understanding of the water cycle and how it is changing will be critical for future decisions related to water management, agriculture, natural resources, and climate change.

Grade level: 9-12
Theme: 21st century technology
Article: documents/21.1_clivar.pdf

CLIVAR (Climate Variability and Predictability) is an international research effort focusing on the variability and predictability of the slowly varying components of the climate system. As part of the US contribution to CLIVAR, a Salinity Working Group was formed and charged with:

	1.	Describing the role of ocean salinity in the global water cycle, global ocean circulation, and climate variability;
	2.	Identifying the requirements and challenges for analyzing, observing, and monitoring salinity, as well as simulating processes critical for determining the ocean's role in the transport and storage of salinity; and
	3.	Providing guidance to the US National Aeronautics and Space Administration (NASA) (and the international community) on observational and scientific activities that should be considered in advance of, and during, the Aquarius mission to improve measurement, analysis, and use of salinity information for the above purposes.

To achieve these goals, sessions on salinity were held at the 2006 and 2008 Ocean Sciences Meetings as well as a workshop at the Woods Hole Oceanographic Institution in May 2006. In July 2007, a CLIVAR white paper on salinity was published (US CLIVAR Report No. 2007-1). The summary and principal recommendations of that report are provided here.

Read and discuss the Priority Recommendations section (p. 83-85).