River - Blog Posts

21 Years of Amazing Earth Imagery

On April 29, 1999, NASA Earth Observatory started delivering science stories and imagery to the public through the Internet. Today, we turn 21! So much has changed in the past two decades... 

One of the most notable changes is the way we view our home planet. Check out some of the beautiful imagery of our planet over the past 21 years.

2000: Pine Island Glacier

Most people will never see Pine Island Glacier in person. Located near the base of the Antarctic Peninsula—the “thumb” of the continent—the glacier lies more than 2,600 kilometers (1,600 miles) from the tip of South America. That’s shorter than a cross-country flight from New York to Los Angeles, but there are no runways on the glacier and no infrastructure. Only a handful of scientists have ever set foot on its ice.

This animation shows a wide view of Pine Island Glacier and the long-term retreat of its ice front. Images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on our Terra satellite from 2000 to 2019. Notice that there are times when the front appears to stay in the same place or even advance, though the overall trend is toward retreat. Read more.

2002: The Blue Marble

In February 2002, Earth Observatory published this “blue marble” image based on the most detailed collection of true-color imagery of the entire Earth at that time. Using a collection of satellite-based observations, scientists and visualizers stitched together months of observations of the land surface, oceans, sea ice and clouds into a seamless, true-color mosaic of every square kilometer (.386 square mile) of our planet. Most of the information contained in this image came from Moderate Resolution Imaging Spectrometer (MODIS), illustrating the instrument's outstanding capacity to act as an integrated tool for observing a variety of terrestrial, oceanic and atmospheric features of the Earth. Read more.

2009: Tsauchab River Bed

The Tsauchab River is a famous landmark for the people of Namibia and tourists. Yet few people have ever seen the river flowing with water. In December 2009, an astronaut on the International Space Station caught this glimpse of the Tsauchab River bed jutting into the sea of red dunes. It ends in a series of light-colored, silty mud holes on the dry lake floor.

Like several other rivers around the Namib Desert, the Tsauchab brings sediment down from the hinterland toward the coastal lowland. This sediment is then blown from the river beds, and over tens of millions of years it has accumulated as the red dunes of the Namib Sand Sea. Read more. 

2012: Manning Island and Foxe Basin, Canada

Although it may look like a microscope’s view of a thin slice of mineral-speckled rock, this image was actually acquired in space by the Earth Observing-1 satellite in July 2012. It shows a small set of islands and a rich mixture of ice in Foxe Basin, the shallow northern reaches of Hudson Bay.

The small and diverse sizes of the ice floes indicate that they were melting. The darkest colors in the image are open water. Snow-free ice appears gray, while snow-covered ice appears white. The small, dark features on many of the floes are likely melt ponds. Read more.

2013: A Lava Lamp Look at the Atlantic

Stretching from tropical Florida to the doorstep of Europe, this river of water carries a lot of heat, salt, and history. The Gulf Stream is an important part of the global ocean conveyor belt that moves water and heat across the North Atlantic from the equator toward the poles. It is one of the strongest currents on Earth, and one of the most studied.

This image shows a small portion of the Gulf Stream as it appears in infrared imagery. Data for this image was acquired on April 9, 2013, by the Thermal Infrared Sensor (TIRS) on the Landsat 8 satellite. TIRS observes in wavelengths of 10.9 micrometers and 12.0 micrometers. The image above is centered at 33.06° North latitude, 73.86° West longitude, about 500 kilometers (300 miles) east of Charleston, South Carolina. Read more.

2016: Curious Ensemble of Wonderful Features

When John Wesley Powell explored the Colorado River in 1869, he made the first thorough survey of one of the last blank spots on the map. The expedition began in May at Green River, Wyoming, and ended three months later at the confluence of the Colorado and Virgin Rivers in present-day Nevada.

About two months into their journey, the nine men of the expedition found themselves in Glen Canyon. As the men traveled along the serpentine river channel, they encountered what Powell later described in Canyons of Colorado as a “curious ensemble of wonderful features.”

From above, the view of Glen Canyon is equally arresting. In 2016, an astronaut aboard the International Space Station took several photographs that were combined to make a long mosaic. The water has an unnatural shade of blue because of sunglint, an optical phenomenon that occurs when sunlight reflects off the surface of water at the same angle that a camera views it. Click here to see the long mosaic.

2019: Lena Delta Shakes Off Water

For most of the year, the Lena River Delta—a vast wetland fanning out from northeast Siberia into the Arctic Ocean—is either frozen over and barren or thawed out and lush. Only briefly will you see it like this.

After seven months encased in snow and ice, the delta emerges for the short Arctic summer. The transition happens fast. The animation above, composed of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on our Aqua satellite, shows the transformation from June 3-10, 2019. Read more.

2020: Making Waves in the Andaman Sea

When tides, currents and gravity move water masses over seafloor features, they can create wave actions within the ocean. Oceanographers began studying these internal waves from ships in the 1960s, and the modern era of satellites has made it possible to see them on a grand scale. The Operational Land Imager (OLI) on Landsat 8 captured these images of the Andaman Sea on November 29, 2019. The reflection of the Sun on the ocean—sunglint—helps make the internal waves visible.

Internal waves form because the ocean is layered. Deep water tends to be colder, denser and saltier, while shallower water is often warmer, lighter and fresher. The differences in density and salinity cause layers of the ocean to behave like different fluids. When tides, currents, gravity and Earth’s rotation move these different water masses over seafloor formations (such as ridges or canyons), they create waves within the sea. Read more.

These images were taken from NASA Earth Observatory! 

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Our Planet: 8 Stunning Views of Earth from Space

Swirling clouds, deep blue oceans and textured land- and icescapes are among the many faces of our planet revealed in NASA’s new photo-essay book: Earth. This collection of 69 images captured by satellites tells a story of a 4.5-billion-year-old planet where there is always something new to see. Earth is a beautiful, awe-inspiring place, and it is the only world most of us will ever know. It is your planet. It is NASA’s mission. The book is available now in hardcover and ebook, and online with interactive features.

Here are eight of those breathtaking images for your viewing pleasure. 

Channel Country, Australia

These wide floodplains in Queensland, Australia are unique on the planet. Scientists think they are caused by the extreme variation in water and sediment discharges from the rivers. In many years there is no rainfall at all, and the rivers are effectively non-existent. In years of modest rainfall, the main channels will carry some water, sometimes spilling over into narrow water holes known as billabongs.

Every few decades, the floodplain carries extremely high discharges of water. For instance, tropical storms to the north can lead to great water flows that inundate the entire width of the floodplain. On such occasions, the floodplain appears as series of brown and green water surfaces with only tree tops indicating the location of the islands. Such is the case in this image taken from the International Space Station in September 2016.

Grounded in the Caspian, Kazakhstan

A wide variety of ice forms in the Caspian Sea, which stretches from Kazakhstan to Iran. Just offshore, a well-developed expanse of consolidated ice appears bright white. Farther offshore, a gray-white field of chunky, hummocked ice has detached and is slowly drifting around a polynya, an area of open water surrounded by sea ice. That darker patch is actually growing young, thin ice and nilas, a term that designates sea ice crust up to 10 centimeters (4 inches) in thickness.

The close-up shows nilas and a white, diamond-shaped piece of ice. It might look like this chunk is on the move, cutting a path through thinner ice. But it’s more likely that the “diamond” was stuck to the sea bottom and the wind pushed ice around it.

Tsauchab River Bed, Namibia

The Tsauchab River is a famous landmark for the people of Namibia and tourists. Yet few people have ever seen the river flowing with water. In December 2009, an astronaut on the International Space Station caught this glimpse of the Tsauchab River bed jutting into the sea of red dunes. It ends in a series of light-colored, silty mud holes on the dry lake floor.

Like several other rivers around the Namib Desert, the Tsauchab brings sediment down from the hinterland toward the coastal lowland. This sediment is then blown from the river beds, and over tens of millions of years it has accumulated as the red dunes of the Namib Sand Sea.

Taranaki and Egmont, New Zealand

The circular pattern of New Zealand’s Egmont National Park stands out from space as a human fingerprint on the landscape. The park protects the forested and snow-capped slopes around Mount Taranaki (Mount Egmont to British settlers). It was established in 1900, when officials drew a radius of 10 kilometers around the volcanic peak. The colors differentiate the protected forest (dark green) from once-forested pasturelands (light- and brown-green).

Named by the native Maori people, Taranaki stands 2,518 meters (8,260 feet) tall, and it is one of the world’s most symmetric volcanoes. It first became active about 135,000 years ago. By dating lava flows, geologists have figured out that small eruptions occur roughly every 90 years and major eruptions every 500 years. Landsat 8 acquired this image of Taranaki and the park in July 2014.

Storms Stir Up Sediment in Bermuda

In October 2014, the eye of Hurricane Gonzalo passed right over Bermuda. In the process, the potent storm stirred up the sediments in the shallow bays and lagoons around the island, spreading a huge mass of sediment across the North Atlantic Ocean. This Landsat 8 image shows the area after Gonzalo passed through.

The suspended sediments were likely a combination of beach sand and carbonate sediments from around the shallows and reefs. Coral reefs can produce large amounts of calcium carbonate, which stays on the reef flats (where there are coralline algae that also produce carbonate) and builds up over time to form islands.

Framing an Iceberg in the South Atlantic Ocean

In June 2016, the Suomi NPP satellite captured this image of various cloud formations in the South Atlantic Ocean. Note how low stratus clouds framed a hole over iceberg A-56 as it drifted across the sea.

The exact reason for the hole in the clouds is somewhat of a mystery. It could have formed by chance, although imagery from the days before and after this date suggest something else was at work. It could be that the relatively unobstructed path of the clouds over the ocean surface was interrupted by thermal instability created by the iceberg. In other words, if an obstacle is big enough, it can divert the low-level atmospheric flow of air around it, a phenomenon often caused by islands.

Lofted Over Land in Madagascar

Along the muddy Mania River, midday clouds form over the forested land but not the water. In the tropical rainforests of Madagascar, there is ample moisture for cloud formation. Sunlight heats the land all day, warming that moist air and causing it to rise high into the atmosphere until it cools and condenses into water droplets. Clouds generally form where air is ascending (over land in this case), but not where it is descending (over the river). Landsat 8 acquired this image in January 2015.

A Lava Lamp Look at the Atlantic Ocean 

Stretching from tropical Florida to the doorstep of Europe, the Gulf Stream carries a lot of heat, salt, and history. This river of water is an important part of the global ocean conveyor belt, moving water and heat from the Equator toward the far North Atlantic. It is one of the strongest currents on Earth and one of the most studied. Its discovery is often attributed to Benjamin Franklin, though sailors likely knew about the current long before they had a name for it.

This image shows a small portion of the Gulf Stream off of South Carolina as it appeared in infrared data collected by the Landsat 8 satellite in April 2013. Colors represent the energy—heat—being emitted by the water, with cooler temperatures in purple and the warmest water being nearly white. Note how the Gulf Stream is not a uniform band but instead has finer streams and pockets of warmer and colder water.

These images are just a few from our new book called Earth. Explore the other 61 images here.

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Flooding Along the Mississippi

Rain, snowmelt, and soil moisture—those three factors might push portions of the Upper Mississippi River into major flooding this spring. Meanwhile, the middle and lower reaches of the river are already well out of their banks.

Intense storms over February 22-24, 2019, caused major flooding along the Middle Mississippi River. On February 25, 2019, the Landsat 8 satellite acquired images of swollen portions of the Mississippi River. The video above shows a false-color view of flooding near Memphis, Tennessee comparing February 2019 to February 2014. Flood waters appear blue; vegetation is green; and bare ground is brown. Notice how the Ohio River and Mississippi River have swelled near Cairo, the southernmost city in Illinois.

National Weather Service forecasters noted that higher-than-average precipitation in autumn 2018 saturated soils in the region, so additional rain or snowmelt from this winter will likely result in excessive runoff and increased flooding threats.

Rapid snowmelt will also play a role in flooding this spring in the Midwest. Parts of Minnesota and Wisconsin have built up snowpack of nearly 25 inches, so melting snow alone could propel many areas into major flooding.

Read the full story here.

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10 Ground-breaking Earth Satellite Images from 2018

In 2018, our satellites captured beautiful imagery from throughout the solar system and beyond. However, some of our favorite visualizations are of this very planet. While this list is by no means exhaustive, it does capture some Earth satellite images from this year that are both visually striking as well as scientifically informative. This list also represents a broad variety of Earth’s features, as well as satellite instrumentation. Take a journey with our eyes in the sky!

10. Hurricane Florence

Before making landfall, Hurricane Florence churned in the Atlantic for a full two weeks — making it among the longest-lived cyclones of the 2018 season. When it finally did hit land on Sep. 14, the storm devastated the southeastern U.S. coast with intense winds, torrential rains and severe flooding.

This natural-color image was acquired by MODIS on the Terra Satellite on Sep. 12, 2018. 

Images like this, as well as other satellite information, were used to anticipate the impact of the storm. Our Disasters Program created flood proxy maps that were shared with the Federal Emergency Management Agency (FEMA) and the National Guard to estimate how many and which communities would be most affected by the storm, in order to help prepare recovery efforts ahead of time.

9. Australia’s Lake Eyre Basin

The Lake Eyre Basin covers one-sixth of Australia and is one of the world’s largest internally draining river systems. However, the rivers supported by this system are ephemeral, meaning that they only run for short periods of time following unpredictable rain — the rest of the time, the Basin is a dry, arid desert.

However, when the heavy rain comes, the basin erupts in an explosion of green. In this false-color image captured by the Operational Land Imager (OLI) on Landsat 8 on Apr. 25, 2018, you can see how the vegetation completely envelops the spaces where the water has receded. (Flood water is indicated by light blue, and vegetation is indicated by light green.)

Satellites are an excellent tool for tracking greening events that are followed by flooding. These events offer opportunities for predictive tools as well as recreation.

8. Alaska’s Chukchi Sea 

A Monet painting comes to life as the Chukchi Sea swirls with microscopic marine algae.

This image was captured off the Alaskan coast by OLI on Landsat 8 on Jun. 18, 2018. After the Arctic sea ice breaks up each spring, the nutrient-rich Bering Sea water mixes with the nutrient-poor Alaskan coastal water. Each type of water brings with it a different type of phytoplankton and the surface waters have just enough light for the algae to populate and flourish. The result is these mesmerizing patterns of turquoise and green.

This image represents one piece of much larger, incredibly complex ecosystem. While one would not normally associate the breaking up of sea ice with phytoplankton blooms, it is an intricate process of the phytoplankton life cycle. The size of the blooms have varied greatly from year to year, and experts are unsure why. Images like these can help scientists track the development of these blooms and link it to other environmental changes.

7. Hawaii’s Kilauea 

Sometimes fresh lava is best viewed in infrared.

This false-color image of Kilauea, captured by OLI on Landsat 8 on May 23, 2018, shows the infrared signal emitted by lava flowing toward the sea. The purple areas surrounding the glowing lava are clouds lit from below, indicating that this image was taken through a break in the clouds.

The Puʻu ʻŌʻō Kupaianaha eruption has been continuously spewing red-hot lava since 1983, making it the longest eruption at Kilauea in recorded history. However, new fissures opened up this year that forced many to evacuate the area. Hawaii’s largest lake evaporated in hours and hundreds of homes were destroyed in Vacationland and Kapoho. 

Imagery, seismometers and ground-based instruments were used to track the underground movement of magma. Infrared imagery can be incredibly helpful in disasters like this when you to view data that cannot be observed with the naked eye. 

6. California’s Woolsey Burn Scar

Nothing quite encapsulates the destruction of a wildfire like a photo from outer space.

This image of the Woolsey Fire aftermath in Southern California was captured on Nov. 18, 2018 by the Advanced Spaceborned Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite. This false-color infrared image has been enhanced to clearly show the burned vegetation (indicated by brown) and the vegetation that survived unscathed (indicated by green).

The Woolsey Fire clearly left its mark, with almost 152 square miles (394 square km) and 88% of the Santa Monica Mountains National Recreation Area badly burned. Images like this one can assist fire managers in the area plan for recovery. 

5. Bangladesh’s Padma River

As the years go by, the Padma River grows and shrinks, twists and turns. It never has a fixed shape, and as a result, thousands of people must regularly adapt to the constant changes in the river’s 75-mile (130-km) shoreline.

This image captured on Jan. 20, 2018 by OLI on Landsat 8 depicts one of the major rivers of Bangladesh. For thirty years, scientists have been tracking the erosion of the river with satellite imagery. Combinations of shortwave infrared, near infrared, and visible light are used to detect differences year-to-year in width, depth, and shape of the river. Sometimes the river splits off, but then rejoins again later. These patterns are created by the river carrying and depositing sediment, shaping the curves of the path of water.

Monitoring the Padma River is going to become especially important as a new bridge development project advances in the Char Janajat area. Although the bridge will most certainly help shorten travel times for citizens, nobody is quite sure how the river erosion might affect the construction and vice versa. 

4. Alaska’s Yakutat Glacier 

It’s hard to believe that Harlequin Lake was once all dry land — but it only started to form once Yakutat Glacier started melting. The lake appeared at the beginning of the twentieth century, and has been growing rapidly ever since.

In this hauntingly beautiful image, captured on Sep. 21 2018 by OLI on Landsat 8, the effect of climate change is apparent — especially when compared to earlier images of the region.

Unless the climate warming starts to reverse very soon — which scientists consider very unlikely — Yakutat could be gone as soon as 2070.

3. South Africa’s Theewaterskloof

Cape Town is a seaside city planted on the tip of South Africa. It’s a city known for its beaches and biodiversity — it also almost became known as the first major city to officially run out of water.

This image of Cape Town’s largest reservoir — Theewaterskloof — was acquired on Jul. 9th, 2018 by OLI on Landsat 8. By the time this photo was taken, the city’s main reservoirs stood at 55%. This was a huge increase from where it stood just six months earlier: just 13%.

The severe water shortage in the region started in 2015, only to become more threatening after three successive and unusually dry years. The entire city was preparing for Day Zero — the day the tap water would be shut off.  

Despite forecasts that Day Zero would arrive in April, a combination of heavier rains and local conservation efforts restored the majority of the reservoir. 

2. Aerosol Earth

Aerosols are all around us. From the smoke from a fire, to the dust in the wind to the salt in sea spray — these solid particles and liquid droplets are always swirling in our atmosphere, oftentimes unseen.

The Goddard Earth Observing System Forward Processing (GEOS FP) model uses mathematical equations to model what is happening in our atmosphere. The inputs for its equations — temperature, moisture, wind, etc. — come from our satellites and ground sensors.

This visualization was compiled on Aug. 24, 2018 — obviously a busy day for aerosols in our atmosphere. Swirls of sea salt (indicated by blue) reveal typhoons Soulik and Cimaron heading straight towards South Korea and Japan. A haze of black carbon (indicated by red) suffuse from agricultural burning in Africa and large wildfires in North America. And clouds of dust (indicated by purple) float off the Sahara desert.

1. Camp Fire

With nearly a hundred fatalities, hundreds of thousands of acres burned and billions of dollars of damage, the world watched in horror as Camp Fire grew to become the most destructive California wildfire in recorded history.

This image was captured on Nov. 8, 2018 by OLI on Landsat 8 on the same day Camp Fire ignited. It consolidates both visible light and shortwave-infrared light in order to highlight the active fire. Strong winds and dry conditions literally fanned the flames and spread this wildfire like a rash. 

This image has not only become the iconic portrait for Camp Fire, it is also sobering representation of how quickly a fire can grow out of control in a short amount of time. Even from space, you can almost smell the massive plumes of smoke and feel the heat of the fires.

Whether you realize it or not, our Earth satellite missions are collecting data everyday in order to monitor environmental changes and prepare for natural disasters.  If your interest is piqued by this list, head over to the Earth Observatory. The Earth Observatory updates daily with fresh, new content — brought to you by none other than our eyes in the sky. 

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