NASA: National Aeronautics and Space Administration NASA Goddard Space Flight Center Home Page NASA Jet Propulsion Laboratory Home Page
NASA Logo - Goddard Space Flight Center NASA | GSFC | JPL | Site Map
Aquarius satellite image Aquarius title
Education: Student Outcomes

Filtered by outcome: 9-12q2
Click here to begin a new search
Outcome: Determine if global precipitation, evaporation, and the cycling of water are changing.
Grade level: 9-12
Theme: water cycle

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 level: 9-12
Theme: water cycle
Flat Tool:
GoogleEarth Interface Tool:

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 level: 9-12
Theme: 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
Theme: 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: 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
Theme: 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
Theme: 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
Theme: 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: 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 level: 9-12
Theme: 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 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 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.