Archives for category: NASA

The Chesapeake Bay is the largest estuary in the United States and third largest in the world. Once sculpted by ice, water, and powerful geologic forces over tens of millions of years, today’s Bay is shaped by human forces as well.

During the past half century, the watershed (image below) has become a landscape full of fast-spreading cities, suburbs, and farms. That development has clouded the water and reduced the productivity of the habitat. Scientists have been monitoring the Bay closely since the 1980s, and the news has often been troubling—waterways polluted with nitrogen and phosphorous, algae blooms, dead zones, and fish kills.

But glimmers of hope have begun to emerge, and efforts to clean up the Bay are starting to make a difference. The gains so far are small, and only careful monitoring will help scientists sort out which aspects of the cleanup are proving effective and which are not.

The series of stories and images below describes the natural and unnatural problems in the Chesapeake watershed, which stretches from upstate New York to Newport News.

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NASA Earth Observatory, December 2016

In 1968, Charles Ichoku was a skinny nine-year-old scouring the jungle in southern Nigeria—a refugee looking for his next meal. A bloody civil war had forced Ichoku’s family to flee their home in Zaria, a city in northern Nigeria, for Nawfia, a village in the south where his parents were born and raised.

For three years, Ichoku, his parents, and five brothers and sisters holed up in remote schools that had been converted into refugee camps. The forest cover around the camps and villages was dense enough to ward off advancing ground troops; it did not necessarily deter aircraft or missiles. Life was strange. Schools were closed; food was almost always scarce.

In the midst of war, Ichoku took solace in the natural world. “I was attracted to the order I found in nature,” he said. “Things fit together in a way that made sense.”

Nearly 50 years later, Ichoku still finds himself looking for order and sense in nature, though for very different reasons and from a very different perspective. As a senior scientist at NASA’s Goddard Space Flight Center, Ichoku uses satellites to study fires. His latest project has brought him back to the region where he grew up, a place where more fires burn per square kilometer than virtually anywhere on Earth.

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NASA Earth Observatory, August 2016


For a chemical compound that shows up nearly everywhere on the planet, methane still surprises us. It is one of the most potent greenhouse gases, and yet the reasons for why and where it shows up are often a mystery. What we know for sure is that a lot more methane (CH4) has made its way into the atmosphere since the beginning of the Industrial Revolution. Less understood is why the ebb and flow of this gas has changed in recent decades.

You can find the odorless, transparent gas miles below Earth’s surface and miles above it. Methane bubbles up from swamps and rivers, belches from volcanoes, rises from wildfires, and seeps from the guts of cows and termites (where is it made by microbes). Human settlements are awash with the gas. Methane leaks silently from natural gas and oil wells and pipelines, as well as coal mines. It stews in landfills, sewage treatment plants, and rice paddies.

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NASA Earth Observatory, March 2016

Image mosaic by Daily Mail.

Image mosaic by Daily Mail.

A few years ago, while working on a story about wildfires, a V appeared to me in a satellite image of a smoke plume over Canada. That image made me wonder: could I track down all 26 letters of the English alphabet using only NASA satellite imagery and astronaut photography?

With the help of readers and colleagues, I started to collect images of ephemeral features like clouds, phytoplankton blooms, and dust clouds that formed shapes reminiscent of letters. Some letters, like O and C, were easy to find. Others—A, B, and R—were maddeningly difficult.

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NASA Earth Observatory, December 2015



(Photo by Martin Wooster.)

In September and October 2015, tens of thousands of fires sent clouds of toxic gas and particulate matter into the air over Indonesia. Despite the moist climate of tropical Asia, fire is not unusual at this time of year. For the past few decades, people have used fire to clear land for farming and to burn away leftover crop debris. What was unusual in 2015 was how many fires burned and how many escaped their handlers and went uncontrolled for weeks and even months.

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NASA Earth Observatory, March 2015



Though it has been quiet during recent decades, Mauna Loa has a long history of volcanic activity. Geologists estimate that the hotspot that feeds Mauna Loa first started to erupt about one million to 700,000 years ago. After underwater eruptions built up a seamount for hundreds of thousands of years, lava emerged above the Pacific surface about 400,000 years ago.

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NASA Earth Observatory, November 2015