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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 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 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 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: 5-8
Theme: ocean circulation
Activity: http://aquarius.nasa.gov/seawater_mix_sink.html

Big Idea

Key Concepts

Background
Density is weight divided by volume. The density of fresh water is 1 gram (mass) per cubic centimeter (volume). In other words, if you had a cube with the dimensions: 1cm x 1cm x 1cm; and filled it with pure water, that cube of water would weigh 1 gram. This density is expressed as 1 g/cm3. If you dissolve salt into the water, the salt will increase the fluid's mass, while its volume will remain the same. Thus, the liquid's density will increase. (more)

Grade level: 5-8
Theme: 21st century technology

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

1. Explain the energy conversions found in the water cycle.
2. Explain the effect of solar energy on the water cycle.
3. Explain the effect of temperature on density.
4. Explain the effect of density on ocean circulation.
5. Explain the effect of solar energy heat on ocean circulation.
6. Explain the effect of solar energy on wind and cloud formation and the effect solar energy, wind and clouds have on climate.
7. Explain that the ocean holds a large amount of heat and the effect this has on climate.

Use the online tools where applicable.

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: 5-8
Theme: climate
Video: atmosphere_ocean_fluids.flv

Currently we have a 50 degree Fahrenheit difference between the temperatures around the equator and the temperatures at the high latitudes near the poles. So that's 50 degrees Fahrenheit difference. Now without those fluids - so if the earth didn't have an atmosphere and the earth didn't have an ocean (which might not make it very livable) - but if we just had a solid land planet, that temperature difference would be 200 degrees Fahrenheit. So it really gives you an idea of how much work those fluids are doing and how much heat they're delivering from the equator to the poles.

Grade level: 5-8
Theme: water cycle
Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf

Activity 4.5: Heat Flow and Latent Heat (p. 37-38). 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 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 latent heat.

When an object gains heat, two things can happen: the temperature of the object can rise, or the object can change its state without a measurable change in temperature (e.g., ice melting into water). Most materials have two state transitions: from solid to liquid and from liquid to gas. The heat needed to change the state of a material is called latent heat of fusion (for changing from solid to liquid) and latent heat of vaporization (for changing from liquid to gas). Latent heats of fusion and vaporization for water are high and have many important consequences for Earth's climate.

Flash Video | QuickTime Movie

Grade level: 5-8
Theme: water cycle
Video: hurricane_cloud_growth.flv

This animation depicts the hurricane cloud growth process. The release of latent heat (shown by orange "blobs") warms the surrounding air, making it lighter, which promotes updrafts (shown as blue arrows) and vigorous cloud development.

NASA's Tropical Rainfall Measuring Mission (TRMM) provides a closer look at hurricanes using a unique combination of passive and active microwave instruments designed to peer inside cloud systems and measure rainfall. TRMM allows scientists to study the combustion process in the hurricane engine and relate this process to intensification or weakening. (source)

Grade level: 5-8
Theme: water cycle
Video: hurricane_latent_heat.flv

This animation depicts the hurricane energy process. As water vapor is evaporated from the warm ocean surface, it is forced upward in towering convective clouds in the eyewall and rain band regions of the storm. As the water vapor changes from a gas to a liquid (cloud water), latent heat is released (shown by orange "blobs"). Red arrows show areas of low atmospheric pressure.

NASA's Tropical Rainfall Measuring Mission (TRMM) provides a closer look at hurricanes using a unique combination of passive and active microwave instruments designed to peer inside cloud systems and measure rainfall. TRMM allows scientists to study the combustion process in the hurricane engine and relate this process to intensification or weakening. (source)

Grade level: 5-8
Theme: water cycle
Video: hurricane_heat_engine.flv

This animation depicts the hurricane heat energy process. As water vapor is evaporated from the warm ocean surface, it is forced upward in towering convective clouds in the eyewall and rain band regions of the storm. As the water vapor changes from a gas to a liquid (cloud water), latent heat is released (shown by orange "blobs").

The release of latent heat warms the surrounding air, making it lighter, which promotes updrafts (shown as blue arrows) and vigorous cloud development.

Red arrows show areas of low atmospheric pressure. It is suspected that rapid bursts of cloud growth, particularly in the eyewall region of hurricanes, may relate to the intensification phase of a storm. (source)

Read Prerequisite Knowledge (p. 2-4).

Grade level: 5-8
Theme: ocean circulation
Video: salinity_importance.flv

The salt in the ocean affects its density, just like the temperature affects its density. And the density, meaning the amount of mass per volume, is going to then impact how the ocean circulates, it's going to impact where the water goes as it circulates throughout the globe.

Grade level: 5-8
Theme: water cycle
Activity: http://www.nasa.gov/pdf/62319main_ICS_Energy.pdf

Water is a key element of the Earth's energy balance. The Sun's energy drives the water cycle, and in turn, water is a major factor in governing the surface temperature of the Earth.

Read the section on Prerequisite Knowledge (p. 2-4).

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: 5-8
Theme: climate
Tool: http://oceanmotion.org/html/resources/winds.htm

This data visualizer includes wind speeds and directions from 1999 to 2008.

Grade level: 5-8
Theme: climate
Video: salinity_and_climate_2.flv

One of the concerns we've had is whether or not the salinity changes will impact what's called the very large-scale ocean overturning circulation, what many people refer to as "the global ocean conveyer belt". And so that overturning of the ocean plays a large role in our climate. And not just (sort of) a climate that we think of in a really abstract sense but it really means a lot for the climate that we live in because that ocean overturning redistributes the heat.

Grade level: 5-8
Theme: climate
Video: salinity_and_climate_1.flv

When these waters at very high latitudes - (your) Greenland, Iceland - when they sink in the wintertime (it's) because they are very dense. Those waters sink, they spread to the global ocean and (eventually) they need to return. When they return, they are returning in the surface waters. That's why it's referred to as an "overturning".

So these warm waters are returning at the surface, going back to those high latitudes in the Norwegian and Greenland seas. And when they're doing that, when they're returning, they're bringing very warm water with them. Because that return means they're coming through the equatorial regions of the tropics where the atmosphere is very warm and the oceans are warmed.

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. So these westerly winds are picking up that heat and moisture and dumping it all over the British Isles and northern Europe. 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.

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: 5-8
Theme: ocean circulation
Video: sst_reverse_direction.flv

The oceans of the world are heated at the surface by the sun, and this heating is uneven for many reasons. The Earth's axial rotation, revolution about the sun, and tilt all play a role, as do the wind-driven ocean surface currents.

This animation shows the long-term average sea surface temperature, with red and yellow depicting warmer waters and blue depicting colder waters. The most obvious feature of this temperature map is the variation of the temperature by latitude, from the warm region along the equator to the cold regions near the poles. Another visible feature is the cooler regions just off the western coasts of North America, South America, and Africa. On these coasts, winds blow from land to ocean and push the warm water away from the coast, allowing cooler water to rise up from deeper in the ocean. (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 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 level: 5-8
Theme: water cycle
Activity: http://www.tos.org/hands-on/teaching_phys_concepts.pdf

Activity 4.7: Thermal Expansion (p. 39-40). 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 thermal expansion.

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 climaterelated 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 percent of observed sea level rise.

In this activity, we look at thermal expansion and attempt to predict what will happen to the ocean's volume if ocean waters become warmer.

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: 5-8
Theme: climate
Activity: documents/vtop_coastal_v_inland_temps.pdf

In this activity, students will use the weather section of the newspaper to help discover why coastal regions have relatively moderate climates. They will construct models of the ocean and the land to measure the different cooling and warming rates of each.

Grade level: 5-8
Theme: climate
Activity: documents/vtop_global_winds_oc_currents.pdf

The surface currents of the major ocean basins show similarities to the prevailing wind systems that drive them. Contained by continental boundaries and deflected by Earth's rotation, these surface currents flow in large, roughly circular patterns called gyres. Gyres play an important role in redistributing heat from the low to middle and high latitudes, thus influencing air temperature, weather, and climate.

After completing this investigation, students should be able to (1) demonstrate the influence of wind on ocean currents, and (2) describe the typical gyre circulation of surface currents in two major ocean basins.

Grade level: 5-8
Theme: climate
Activity: documents/vtop_oc_currents_coastal_temp.pdf

The surface currents of the major ocean basins show similarities to the prevailing wind systems that drive them. Contained by continental boundaries and deflected by Earth's rotation, these surface currents flow in large, roughly circular patterns called gyres. Gyres play an important role in redistributing heat from the low to middle and high latitudes, thus influencing air temperature, weather, and climate.

After completing this investigation, students should be able to (1) demonstrate the influence of wind on ocean currents, and (2) describe the typical gyre circulation of surface currents in two major ocean basins.

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)