Archives for category: Earth Observatory

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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

 

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(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

IDL TIFF file

 

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

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Few images are as beautiful and as terrifying as a satellite view of a hurricane about to make landfall. On October 29, 2012, the Suomi NPP satellite captured an ominous nighttime view of Sandy—an enormous hybrid storm that was part hurricane, part Nor‘easter—churning off the coast of New Jersey.

The string of city lights that stretches from Washington to Boston was mostly gone, blanketed by thick, ghostly storm clouds. One of the most brightly lit cities in the world, New York, was little more than a faint smudge through Sandy’s clouds.

In a matter of hours, that smudge of light would go dark. Large swaths of Manhattan were under water. The Rockaways were on fire. Rooftops along the New Jersey shore became temporary islands for people escaping a wall of seawater that surged inland.

Was Superstorm Sandy an expression of a “new normal” for our weather? Was it a storm pumped up by global warming?

“If you look at the unique set of circumstances in which Sandy emerged and you know something about meteorology and climate,” says Marshall Shepherd, director of the atmospheric sciences program at the University of Georgia, “it’s hard not to ask yourself these kinds of questions.”

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NASA Earth Observatory, March  2013

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When astronauts talk about viewing Earth from space, the conversation often turns to the planet’s mesmerizing beauty. They describe views of aquamarine coral reefs glimmering amidst the deep blue ocean; of armies of sand dunes marching across deserts; of clouds and lightning flashes dancing through the atmosphere.

For many, the view is deeply humbling. “For the first time in my life, I saw the horizon as a curved line. It was accentuated by a thin seam of dark blue light: the atmosphere,” said Ulf Merbold, a German astronaut who flew on Space Shuttle Columbia in 1983. “This was not the ‘ocean’ of air I had been told it was…I was terrified by its fragile appearance.”

For some astronauts, that thin blue line has appeared quite vulnerable. Many have noticed palls of haze lingering over parts of the world, the result of millions of tiny particles drifting in the atmosphere. Aerosol particles, which can be either liquid or solid, obstruct sunlight and cause distinct and vibrant features to blend into a hazy, featureless mélange of gray.

The particles that affect visibility have many sources, some of them natural. For instance, winds blow bits of dust and dried soil aloft; volcanoes occasionally belch thick plumes of ash; forest fires produce smoke; even vegetation and plankton can emit substances that contribute to haze.

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NASA Earth Observatory, June 2014