Month: July 2010

A Tale of Two Kenyas: Contradictions in Air Quality Stirred Researcher’s Pursuit of Atmospheric Science

Charles Kironji Gatebe’s early years read like a cliché. He grew up barefoot and poor in the small Kenyan village of Kenda at the foot of Mount Kenya, the son of coffee sharecroppers who raised their family on pennies a day. He walked nearly 10 miles each way to school for nearly a decade. He lacked adequate texts and other school supplies.

What he didn’t lack on those long daily walks was clean air. It was the contrast between the clear skies of his boyhood home and the smog and fumes of the nation’s capital, Nairobi, that stirred within Gatebe a strong passion for science. In 1979, Gatebe (right) was selected to represent his elementary school at a national convention to celebrate the United Nations Educational, Scientific and Cultural Organization’s (UNESCO) International Year of the Child. He later won a physics prize in high school in 1984 from the Kenya Secondary Schools Science Congress. He enjoyed independent research so much that his physics teacher would allow him to conduct his own experiments in the lab alone at night or on weekends.

Gatebe’s passion, matched with natural aptitude, eventually led Gatebe to degrees from Kenya’s University of Nairobi and the University of the Witwatersrand in South Africa. Now a climatologist with a joint appointment at NASA’s Goddard Space Flight Center and the University of Maryland-Baltimore County, Gatebe has fashioned an award-winning career – including the rare honor of the World Meteorological Organization’s Young Scientist Award in 2000, and awards from the Kenyan government, German Academic Exchange Services, SysTem for Analysis, Research and Training (START), and the International Program in the Physical Sciences — for his innovative research on air pollution and its sources and effects on his country.

“Air quality in Kenya’s villages was and continues to be significantly different from the smog encountered in Nairobi. They vary so much that it seems you’re virtually in two distinct countries,” said Gatebe when asked to share what sparked his study of Kenya’s air pollution. During his graduate studies at the University of Nairobi, he devised a few climate projects that unexpectedly got the attention of the Kenyan government and United Nations Environment Program. One of those was a modeling experiment to measure vehicle pollution and predict pollution levels from the average speed and number of cars in use.

Gatebe also investigated the origins of the city’s air pollution; that is, how much Nairobi’s citizens and industry generated compared to what was transported in from other countries. “Charles’ Kenyan air quality research was quite breathtaking and significant,” said Michael King, a senior atmospheric scientist at the University of Colorado and former senior project scientist at NASA Goddard who recruited Gatebe to NASA in 1999. “It involved him regularly hiking to the top of Mount Kenya – which sits roughly on the equator — and collecting air samples of atmospheric aerosol particles that he analyzed for their composition to distinguish dust and other particles from local sources from pollutants arriving from as far away as southern Africa, India and the Sahara.”

The acclaim from the study came as a surprise, Gatebe says, but motivated him to stay the course. He knew he’d found his niche.

As a former child scientist, Gatebe is eager to inspire more kids to get involved in science. He’s dedicated himself to NASA’s Global Learning and Observations to Benefit the Environment (GLOBE) education program, and blogs about the science of current events for GLOBE’s Web site.

Gatebe’s latest work is based on what he calls an accidental discovery, not uncommon in science. In summer of 2008, he was part of a NASA field mission called Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS). Arctic wind currents can carry a haze that affects local climate. Gatebe and colleagues flew aboard planes through smoke blown over the Pacific Ocean from land-based fires to evaluate the composition of the pollution that eventually forms Arctic haze. 

A ship passed beneath Gatebe’s plane, through his measurement field, triggering a mass of sea foam in its wake. When he later evaluated visible and near-infrared data from NASA’s Cloud Absorption Radiometer instrument that took the measurements from aboard the plane, he noticed a spike in brightness in the vicinity of the ship’s path. The bubbles in the wake increased light reflectance off the ocean.

The irony of the discovery was quite amazing to Gatebe. Ships were long thought to pollute the air and contribute to warmer climate through exhaust emissions. But they also appear to have a counterbalancing effect of cooling local ocean surfaces by as much as four percent. What he doesn’t know yet is just how much the cooling effect offsets the warming effect on the nearby environment. He hopes that others will further the work so the question doesn’t go unanswered.  

–Gretchen Cook-Anderson, NASA’s Earth Science News Team


Charles K. Gatebe (top, courtesy of C. Gatebe);  Zebras with hazy Nairobi in the distance (bottom, courtesy of Michael King).  

NASA Earth Buzz

Earth science links, video, and more that caught our eye…


Tragedy in the Gulf
Heartbreaking video (above) from NASA shows a time-series of satellite snapshots of oil tendrils as they spread through the Gulf of Mexico. The video has appeared on the New Yorker and Gizmodo web sites and has garnered more than 600,000 views on YouTube. (NASAExplorer)

Who CARES About Urban Aerosols?
NASA scientist Matteo Ottiviani is blogging from an airborne field campaign in California, and he has a gift for making aerosols (small particles in the air, not the spray cans) sound exciting.   (Notes from the Field)

NASA Expedition Heads to the Arctic
Yep, we work from ships, too. A NASA-funded expedition has set sail for the Beaufort and Chukchi seas above Alaska to study the ecological impacts of sea ice decline. (IceScape Blog)

Supercomputing Climate Simulation Center Debuts
Many skeptics point to erratic models as the Achilles heel of climatology. A recently unveiled supercomputing center at Goddard, packed with more than 10,000 computer processors, should help. (NASA.gov)

Sensing the Sun’s Irradiance
Little fluctuations in the sun’s output might have more impact than you might think. A Q & A with the Glory Mission’s Judith Lean explores what it all means for climate. (NASA Earth Observatory)

New Earth Observer Is out
NASA’s bimonthly newsletter Earth Observer has news about IceSat, IceBridge, sea ice and more. It’s a somewhat technical read, but worth checking out. (Earth Observer – PDF)

Tweet of the Week
Why is permafrost like frozen chicken? http://go.usa.gov/3Ka (@NASA)

Though you may not know it, NASA has tens of thousands of websites devoted to earth science. It would be a Herculean task to keep track of all of them, so we created this column to save you the trouble. We’ll periodically scour what NASA has to offer and serve up the most fascinating, surprising, and thought-provoking Earth science we stumble across. Think we missed something? Post a comment in the most recent Earth Buzz.

–Adam Voiland, NASA’s Earth Science News Team

Beautiful Radiance

Karen Romano Young (right), a freelance writer and illustrator embedded with NASA’s ICESCAPE field campaign, sent this report from an icebreaker headed to the Arctic. You can follow the expedition on the ICESCAPE blog. 

Here on the U.S. Coast Guard Cutter Healy, heading north toward sampling stations in the Bering Strait, there’s plenty of light — a beautiful radiance nearly around the clock. Since arriving in Alaska on June 12, I’ve only awakened once in the middle of the night to find it dark. Last night at nearly 11 p.m., I sat drinking tea in front of my porthole, and saw a rainbow descend between strips of clouds into the grey Bering Sea. We’re in the land of the midnight sun, and as we continue north the night light will grow longer. It’s the opposite of the conditions that lead to Seasonal Affective Disorder down south where I come from (Connecticut!) For me, it’s joy.

Up here where there used to be more ice, the radiance is, well, radiating. This is the key: the Arctic ice reflects sunlight back into space. If there’s no ice, the sunlight goes into the water, warming it, and creating an environment in which phytoplankton — tiny plantlike algae at the water’s surface — can thrive. There’s less ice because our atmosphere is trapping greenhouse gases — carbon dioxide and methane — and the result is a warming Arctic.

Many of the 40-plus scientists participating in ICESCAPE, a NASA-led research cruise, are involved in studying the effects of sunlight. ICESCAPE stands for Impacts of Climate Change on the Eco-System of the Arctic Pacific Environment, and its purpose is to bring ice scientists and ocean scientists together to gather a greater understanding of the conditions in the Bering, Chukchi, and Beaufort Seas.

Who better to begin a discussion of the sun’s warming effects than a University of Washington scientist named Bonnie Light? Light has been working in the Arctic Ocean since 1998 when, as a grad student, she boarded the Canadian icebreaker Des Grosseilliers, which had purposely pulled up to the edge of the 1997 autumn ice and got fro-zen in through the 1998 thaw. That was the SHEBA (Surface Heat Budget of the Arctic) project, designed to increase understanding of the Arctic system.

Getting frozen in to the ice was a nod to the so-called “father of Arctic science,” Fridtjof Nansen, who purposely did the same a century earlier to prove his theory that the ice cap drifted. One of the purposes of SHEBA was to provide a baseline for under-standing Arctic conditions that might be affected by global warming. Several other scientists aboard ICESCAPE also participated in SHEBA, including Bonnie’s group leader and co-chief scientist Don Perovich.

The flight to the SHEBA site from Barrow, Alaska — the northernmost city in the United States — was the first time Light saw sea ice. “I’d calculated the total square kilometers that the Arctic ice cap occupies many, many times,” she said, “but to be in a little air-plane and fly over it and just see it…this endless stretch of pack ice was really striking.” During the ICESCAPE cruise she is eager to explore the western coast of Alaska for the first time.

“People have told me that the sea ice in the Chukchi Sea has already begun to open up and is very loose this year,” Light says. She expects to be one of the “ice party,” the group of scientists that descends from the deck of the Healy (shown left), via a basket dangling from a crane, to work on the ice. “I don’t know if we’ll get out on it or not. We’ll have to just wait and see what it looks like when we get there. It’s something I’m not sure a satellite can tell you.”

Light is interested in the physics of solar irradiance – what happens to the sun’s light in ice on a small-scale, but also at the larger scale of the melt ponds that form atop sea ice. One of the experiments she’ll conduct involves a comparison of how sun radiates through bare ice and ice that has a melt pond on top. “We already know that melt ponds make really good skylights,” she says. But could they accelerate melting of already-melting ice, hastening the tipping point between ice cover and open sea? Bonnie Light’s ICESCAPE experience could tell.

Image Information: Courtesy of the U.S. Coast Guard (bottom left) and Karen Romano Young (top right).

What's a Wallops?

What’s a Wallops?

The question, posed by an educated Virginia resident, illustrates a general unawareness that the state is home to one of the world’s oldest launch sites — NASA’s Wallops Flight Facility.

The facility, named after John Wallop who was granted the land in 1692, launched its first rocket on July 4, 1945 and has since launched more than 16,000 vehicles. Beyond launches, however, Wallops is home to other modes of space and Earth science, many of which were on display June 5 at an open house celebrating the center’s 65th anniversary.

Perhaps it’s the center’s location that keeps it hidden from the public eye. Nestled 200 miles away from urban areas, on Virginia’s eastern shore near Chincoteague Island, the coastline provides a prime location for launching suborbital and orbital rockets, targets for the military and testing unpiloted aerial vehicles. Being next to the ocean allows NASA to safely test unproven vehicles and also provides a location for conducting coastal Earth science studies.

Wallops hosts a scientific balloon program, on display at the 65th open house. Adrift at high altitudes in Earth’s atmosphere, balloons carry instruments that measure emissions from space, contributing most to astrophysics research. Credit: NASA



Scientists and engineers at Wallops worked with the laser instrument on NASA’s Ice, Cloud, and land Elevation SaESat)that measured the surface elevation of ice until fall 2009. The publiccould learn more about ICESat and plans for ICESat-2 during the openhouse. Credit: NASA


Perhaps the largest draw was the research airport. U.S. Air Force Thunderbirds lined up on the tarmac before taking off for a demonstration at an air show in Ocean City, Md. Credit: NASA

Wallops’ location also lends itself to Earth science research, described in the center’s roadmap as having “a focus on global climate change and the unique dynamics of the coastal zone environment.”

For example, scientists at Wallops have experimented with autonomous boats to study the ocean and atmosphere, and the interaction between the two environments.

From a distance, visitors saw a more science inclined aircraft, NASA’s very own P-3, just back from a mission in Greenland where it surveyed Arctic ice.

Missed the open house? Learn more about Wallops here.

— Kathryn Hansen, NASA’s Earth Science News Team