Ice on the Dnieper River, Ukraine

March 31, 2012 //
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After an unsually cold winter in Ukraine, the spring melting of the Kyiv (or Kiev) Reservoir on the Dnieper Riverhas caused potentially hazardous rafts of ice to start drifting toward a dam and hydroelectric plant at the southern edge of the reservoir.

When the Advanced Land Imager on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-color image on March 17, 2012, open water still surrounded the dam, but many pieces of ice were visible just to the north. Although Ukrainian authorities are monitoring the dam closely, they believe the risk that the dam will fail is small.

The average thickness of the ice on the reservoir is about 40 centimeters (16 inches), half what it was in 2011 when heavy flooding prompted officials to abruptly lower the water level of the reservoir. According to the National Radio Company of the Ukraine, the CEO of the company that operates the dam doesn’t expect similar action will be needed this year.

Earth Observatory, March 2012

Categories 2012, Earth Observatory, NASA

Satellites Map Fine Aerosol Pollution Over China

March 23, 2012 //
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Many types of aerosol particles circulate in the atmosphere, but one of the most damaging to human health is known as PM2.5, a technical term for microscopic bits of matter less than 2.5 microns in diameter (one thirtieth the width of a human hair). These small pollutants, which come mostly from burning fossil fuels and biomass, can lodge deep in the lungs, where they exacerbate a variety of respiratory and cardiovascular diseases.

Ground-based instruments are the standard for monitoring PM2.5 in many industrialized nations. For example, the U.S. Environmental Protection Agency, along with state and local governments, maintain a network of about10,000 ground stations that generate real-time air quality measurements for hundreds of cities. Such data gets funneled into services like AIRNow, which issues warnings when pollution reaches unsafe levels.

However, not all countries have ground-based monitoring systems that measure such fine-grained pollutants.China, like most countries, has traditionally only monitored a larger type of particle pollution known as PM10. Though Chinese leaders have announced a plan to monitor PM2.5 more broadly in the future, to date only a handful of cities have started to publish PM2.5 numbers.

Satellites offer a perspective on PM2.5 that is particularly useful when ground instruments are unavailable or offer limited information. With that in mind, researchers at Columbia University’s Earth Institute and Batelle Memorial Institute have developed maps based on satellite data that depict annual PM2.5 exposure in all of China’s provinces.

The map above, which shows annual exposure between 2008-2010, indicates that most areas had PM2.5 levels that exceeded World Health Organization guidelines (10 micrograms per cubic meter). Areas surrounding Beijing and to the south along the coast, which fall in China’s industrial heartland, had the most pollution. In many cases, annual exposure was above 40 micrograms per cubic meter. Other provinces in eastern and south central China had pollution levels above 30 micrograms per cubic meter. For comparison, the New York, Chicago, and Los Angeles metro areas have PM2.5 levels that average between 10 and 20 micrograms per cubic meter.

The values used to create the map were derived from a method that Dalhousie University scientist Aaron van Donkelaar developed and published in Environmental Health Perspectives in 2010. At the time, van Donkelaar released a global map of PM2.5 pollution. Both that map and the map above are based on data from the Multi-angle Imaging Spectroradiometer (MISR) instrument on the Terra satellite, the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on the Terra and Aqua satellites, and a chemical transport model calledGEOS-Chem.

While satellite measurements are the best option in areas with limited ground monitoring, they are not without shortcomings. Satellites, for example, have difficulty detecting pollution over bright surfaces, such as snow and deserts. Overall, the researchers say the uncertainty amounts to about 6.7 micrograms per cubic meter.

NASA Earth Observatory, March 2012

Categories 2012, Aerosols, Air Quality, Earth Observatory, NASA

Effects of the Tohoku Tsunami on the Kitakami River

March 11, 2012 //
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In March 2012, a magnitude 9.0 earthquake—the fourth largest recorded since 1900—triggered a powerful tsunami that pummeled the northeastern coast of Japan. The earthquake occurred offshore, about 130 kilometers (80 miles) east of Sendai at 2:46 p.m. on March 11. Within 20 minutes, massive swells of water started to inundate the mainland.

The tallest waves and most devastating flooding from the 2011 T?hoku-oki tsunami occurred along the jagged coast of northern Honshu, a landscape dimpled with bays and coves known as ria coast. The steep, narrow bays of ria coasts trap and focus incoming tsunami waves, creating destructive swells and currents that can push huge volumes of water far inland, particularly along river channels.

That’s exactly what happened in the days before the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), an instrument on NASA’s Terra satellite, captured the middle image above (on March 14, 2011). It shows severe flooding along the Kitakami River three days after the earthquake struck.

Earth Observatory, March 2012

Categories 2012, Earth Observatory, Earth Science, NASA

Ship Tracks off the California Coast

March 7, 2012 //
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Ships churning across the Pacific Ocean left this cluster of bright cloud trails lingering in the atmosphere late last month. The narrow clouds, known as ship tracks, form when water vapor condenses around tiny particles of pollution that ships either emit directly as exhaust or that form as a result of gases within the exhaust.

The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite captured this natural-color image on February 21, 2012. The criss-crossing clouds off the coast of California stretch many hundreds of kilometers from end to end. The narrow ends of the clouds are youngest, while the broader, wavier ends are older.

Some of the pollution particles generated by ships (especially sulfates) are soluble in water and can serve as the seeds around which cloud droplets form. Clouds infused with ship exhaust have more and smaller droplets than unpolluted clouds. As a result, light hitting the ship tracks scatters in many directions, making them appear brighter than other types of marine clouds, which are usually seeded by larger, naturally occurring particles such as sea salt. (In this image, the ship tracks don’t appear particularly bright because the surrounding clouds are also fairly bright. But in this March 2009 image and this July 2010 image the brightening effect of the pollution is quite clear.)

The enhanced reflectivity of ship tracks means they shade Earth’s surface from incoming sunlight, which produces a local cooling effect. However, determining whether ship emissions have a broader climate effect is complex because ships also emit pollutants that have a warming influence, such as carbon dioxide and black carbon. Research is ongoing, but one recent satellite study found that ship emissions do not cause changes on a large enough scale to affect climate significantly.

At the same time, researchers have shown that the ship emissions pose a clear hazard to human health. Seventy percent of all ship tracks occur within 500 kilometers of the coast, which means shipping exposes large numbers of people in coastal cites to high levels of health-sapping particulates. One study concluded, for example, that shipping-related particulate matter is responsible for 60,000 premature deaths each year, about 5 percent of the total premature deaths associated with particulate air pollution each year.

Earth Observatory, March 2012

Categories 2012, Earth Observatory, Earth Science

Slurry Install and Opening

February 21, 2012 //
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I spent much of Sunday in Westminster, Md. helping Katherine prepare for the opening of her new show at McDaniel College’s Rice Gallery.  The show –  Slurry — opened on Feb. 21 and runs through March 16. We (well, Katherine mainly) spent many hours taping down the expansive piece that you’ll see creeping across the gallery floor and up a wall if you visit. While we were packing the car, I had some fun taking periscope photos of the rolled-up paintings. Click on the slideshow for a larger view of the photos.

Categories 2012, Art, Katherine Mann, Openings

Races & Places: An Uphill Battle

February 12, 2012 //
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Photograph by David Clifford

It’s 6:59 a.m. in Aspen, Colorado. Elevation: 7,945 feet. I’m on a tongue of groomed powder at the base of a ski spot that overlooks downtown. A pack of about 200 Lycra-clad racers fidgets behind a blue line spray-painted in the snow. The horn will blow any second.

I glance down and around. I’ve never seen such an array of footwear at a starting line. To my right, a scatter of ski bindings, from Nordic to randonée. To my left, a woman fusses with snowshoes. Ahead: a burly guy in jerry-rigged Nike trainers.

But then again, I’ve never run a race quite like America’s Uphill. It’s 2.7 miles of brutal snow-covered slopes beginning at the bottom of the Aspen Mountain Gondola and ending at its 11,212-foot summit. The race offers a 3,267-foot climb—more vertical than the world’s tallest building.

Racers can use whatever gear they want, and some come better prepared than others. Just days off a jet from Washington, D.C., I’m one of the others. My wife is concerned that I will keel over midrace with mountain sickness. I kiss her forehead saying, “I’ve done marathons before. How hard can a few miles be?”

I’ve long believed that less is more when it comes to footwear. My shoes: Puma racing flats enveloped by a tangle of rubber and metal. Yesterday, I’d shelled out $60 for attachable crampons. The web of 3/8-inch steel spikes slips under the wafer-thin soles like a net. I’m in the “Open” division, a catch-all category that includes shoe stabilizers, Yaktrax, and the like. The other three categories are track skis, telemark skis, and alpine touring (which includes alpine and randonee bindings).

The horn blares. The pack begins to ooze across the starting line. Only a handful of us are running. Most are engaged in more of a waddle. I’m taken aback. I thought this was a race, not a charity stroll. I vow to maintain at least a shuffle.

But quickly the reality of the mountain—and the thinness of the air—hits me. Hard. The race has barely begun, but I can hardly breathe. I feel like I’m drowning. Ten-thousand feet up, high enough that each lungful contains only three- quarters of the oxygen I would get in D.C.

As I head higher, I play mind games to keep moving. I shut my eyes, count steps, tell myself there’s a serial killer chasing me. I imagine I’m wearing rubber boots and slogging through puddles of paint inside one of my wife’s paintings. It helps.

So does turning and looking back. Just after the halfway mark, the view, which had been blocked by a row of trees before, spreads out around me like a tapestry of green and white. Whole ridges of mountains in the distance, imposing from the ground, look like anthills from up here.

I draw strength from the view, and soon I’ve made my way up through a narrow notch in the path that opens up to an area where the morning light, a huge pool of gold, sparkles across the top of the mountain. I start to feel euphoric. For maybe 10 minutes. My heart, meanwhile, is thud- ding three times faster than it should. Each breath is sandpaper on my windpipe.

Toward the end of the race, my spikes feel like they’re chiseling nails through the soles of my feet. Finally, I see the Sundeck Restaurant perched at the sum- mit. I rush toward it. In the last stretch, which flattens out a bit, I accelerate to a shuffle. When I cross the finish, the clock reads 1 hour 17 minutes—right in the middle of the pack. Normally, I’m in the top 15 percent.

My wife hugs me. Sheepishly, I admit: “Those were the toughest 2.7 miles of my life.”

Runner’s World, March 2012

Categories 2012, Adventure, Runner's World, Running
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