Author: Steve Cole

by Ellen Gray / WALVIS BAY, NAMIBIA /

Stu Broce loves flying high.

“The view is incredible. You can see 300 miles away,” he said from the cockpit of NASA’s high-altitude ER-2 research aircraft. “You can see the curvature of the Earth. If you look up, the sky is very dark blue.”

Of course, for the ORACLES mission now in Namibia studying low-level clouds and aerosols over the south-east Atlantic Ocean, the view of never-ending white is not going to be quite so exciting for the pilots, he added with a grin. There’s more to flying high than the view.

“I kind of like the solitude, too. It’s my happy place. No matter what’s going on in my life, when I close the canopy, and especially when I leave the ground, I know I’ve got 12 hours of alone time. Busy alone time,” Broce said.

A retired Navy pilot, Broce flew commercial for nearly a year before post-9/11 furloughs led him back to the military, this time the Air Force, where he learned to fly the high altitude aircraft. As luck would have it, around the time he was retiring, NASA was hiring, and Broce has been flying the ER-2, as well as other aircraft, for NASA for the last five years at Armstrong Flight Research Center in California. He’s one of two pilots flying the ER-2 for the ORACLES mission this month.

It’s a challenging aircraft to fly. Landing in particular. “It’s like landing a big 30,000 pound bicycle,” he said. The ER-2’s two main sets of wheels are under the body. The wheels that prop up the wings on the ground drop off during take-off and don’t fly.

The ER-2 is a small, lightweight airplane with a single occupant: the pilot. Its job is to get the long view of the clouds below. Tucked into its nose, body and a pod under each wing, the ER-2 carries four remote-sensing instruments to 65,000 feet, twice the altitude of commercial airliners.

“The only people higher than us are the astronauts in the space station,” said Broce. “We fly so high, we fly above Armstrong’s line at 60 to 62,000 feet, where if you took a cup of water at altitude outside the plane, the water would boil just because of the low pressure there, even though it’s super cold.”

People don’t do so well at those low pressures. The pilots wear space suits that will pressurize in case of a loss of cabin pressure. Part of their prep is to breathe pure oxygen for an hour before flight to purge the nitrogen from their bodies so they don’t get the bends when they ascend so quickly. Food and water for the eight plus hours in flight both come through a tube – applesauce, pear-sauce, and peach-sauce are among Broce’s favorites, which he said are actually pretty good.

The instruments, on the other hand, do great at 12 miles above the Earth. While they’re not as high as satellites, some of the instruments simulate satellite measurements. Aboard the ER-2 they both test out new technology and software and get the equivalent of satellite data right where the scientists want it.

The science team is trying to understand the interaction of clouds and tiny airborne particles – smoke from fires central Africa – and how they change the amount of energy absorbed or reflected from the clouds, a key component for assessing how clouds affect Earth’s climate.

Broce helps out with gathering the data. The instruments are as fully automated as can be, but he still needs to turn them on after take-off and sometimes during flight switch their modes.

“I like to count the number of button presses per hour. It’s ‘BPH’ — my term. If it’s above ten, I consider that busy because you have to read checklists and know when to hit the button and check miles and time and locations. We also have to navigate and fly the plane, sometimes to precise navigation or headings, and then push the buttons.”

At the end of the day, the goal is to return measurements to scientists waiting on the ground.

For more on Broce’s work as ER-2 pilot for ORACLES, visit Notes From the Field: ORACLES in Namibia 2016.

(Note: This wraps up our reporting from Namibia. Click here for all the ORACLES blog reports.)

 

 

by Ellen Gray / GOBABEB, NAMIBIA /

Brent Holben stands in the shade of his car’s hatchback door, squinting at his phone. He’s checking Google Maps. From the dirt parking lot at the Walvis Bay Airport, Namibia, he temporarily has free internet access to the NASA wifi hotspot set up for NASA’s ORACLES airborne science campaign here.

“I don’t want to make a wrong turn,” he says. “Of course out here, that’s pretty hard. There’s not many turns.”

With a trim gray beard and brimmed hat, Holben, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is in charge of the ground sites that will measure aerosols to complement observations made by ORACLES’s two research aircraft.

Today, Holben is heading out on a road trip southeast of Walvis Bay to the Gobabeb Research and Training Centre, 40 miles as the crow flies from the coast. There, perched atop a short tower, is one of Holben’s aerosol measuring instruments, a sun photometer that is part of the Aerosol Robotic Network. AERONET, which began in 1992 with two sensors, now has 600 sensors worldwide, but not as many in Africa as Holben would like.

“Africa is a giant place, and it’s underrepresented compared to Europe and the United States.” Holben is the AERONET project scientist.

As ORACLES was being planned to make measurements of aerosols over the southeast Atlantic Ocean from aircraft, he originally drafted plans for two AERONET instruments in Namibia that would study aerosols from the ground. He ended up setting up ten.

A sun photometer has one job: to look at the sun to see how many aerosols are between it and the ground by measuring the light energy that reaches the instrument.

“If the set-up weren’t simple, I wouldn’t do it,” Holben said of the solar-powered instrument.

But simple doesn’t mean without complications. One reason Holben is visiting Gobabeb is because he’s concerned about the instrument shutting down unnecessarily due to the region’s characteristic fog.

The sky is overcast on our drive south, which is not uncommon along the Namibian coast. Early morning fog develops when warm air condenses over the cold ocean water, and then it rolls over the length of the coast and inland. It’s the main source of water for much of the vegetation that grows where it can across the plain.

Not far from the airport the asphalt disappears and we’re driving on a dirt road. To either side the rocky desert is white-beige and flat, textured with small rocks and dotted with occasional buildings that grow fewer and farther between.

On the horizon ahead, great sand dunes appear, first as bumps, then looking like orange mountains. Eventually, a green strip comes into view at the base of the dunes. Holben points out as the green strip resolves into trees. “That’s the river.”

The river is the Kuiseb (pronounced kwee-sib), and it’s dry for most of the year.  During the rainy season from November to January or so, it may have water for a few months, replenishing the groundwater for the trees – and everything that eats their leaves – to live on for the rest of the year.

The road turns east and from here parallels the river into the Namib-Naukluft Park and to Gobabeb Centre where it dead-ends. Along the way are the farms of the local Topnaar community, which has lived along the Kuiseb for the past 600 years. Many have day jobs in Walvis Bay to supplement their living. Along the river they raise cattle and other livestock.

“It’s a harsh existence. You’ve got to admire people who eke out a living here,” said Gillian Maggs-Kölling, the Gobabeb Centre’s executive director. The centre is located next to three ecosystems: the rocky plain, the linear oasis of the river, and the 1,000-foot sand dunes that roll into the Sand Sea to the south.

Maggs-Kölling is a biologist, as are most of the 18 researchers and students who live and work there. It’s an international mix, with students from the Namibian University of Science and Technology joined currently by a group from the University of Basel in Switzerland, and a handful of others from various other European and American universities.

The main building with labs and offices is surrounded by a spread of low cottages and gardens of scientific instruments measuring temperature, moisture, and a dozen other things. Completely off-grid, the site is powered by solar panels with the occasional help of a generator.

This is Holben’s third trip to Gobabeb, one each year since setting up the AERONET sensor here.

“We came here because we didn’t have an instrument in this part of the world. The Namib Desert is quite unique because it is influenced by fog,” said Holben. He and the ORACLES team hope to learn how the aerosols they’re measuring affect the fog and the clouds over the ocean.

We meet Monja Gerber, a relatively new technician and Masters student in plant physiology from North West University in South Africa, who is taking care of the instrument this year.

Atop the two-story tower where the AERONET instrument sits, Holben shows Gerber a few maintenance tricks. The instruments tube is open and sometimes spiders or bees like to make homes in them, he points out. Holben shows her how to disconnect the wet sensor that triggers when fog collects on it.

As the day warms, morning fog that rolls in from the coast clears. Using its own GPS location and the time of day to find the sun, the AERONET photometer spins into action.

“We’re looking at two main aerosols in this region. Dust blown from the desert is one, which is actually a very small component. The big one is smoke from fires in central Africa. These are man-made agricultural fires as people clear their land at this time of year,” said Holben.

Westerly winds take the smoke from the Democratic Republic of Congo, Zambia, and Angola, and carry it out over the southeast Atlantic, where ORACLES’s two research aircraft measure it to see how the smoke changes sunlight absorption or reflection – important to know for understanding and predicting climate change. That smoke arcs back to Namibia on south-easterly winds.

“We’ve been watching the aerosols day by day for ORACLES,” Holben said of both the measurements here at Gobabeb and the six sensors that are set up in Henties Bay, an hour north of Swakopmund. “Over the last several days, the optical depth went from almost background conditions to – yesterday – moderately high.”

Light scattered by the smoke aerosols makes sunsets here red, Holben added.

The sunset is spectacular. Holben and his son Sam, who accompanied him on the trip, cross the river and climb to the top of the nearby dune to watch. They leave with barely enough time, and Sam, not wanting to miss it, runs ahead and picks the steepest ascent.

Climbing a dune of fine sand is not easy, and he slides down nearly as much as he climbs, but persistence gets him to the top. Holben takes a less-steep approach and settles in for the show.

From the top, the Namibian landscape stretches as far as the eye can see, changing colors as the sun sinks behind the dunes in the west. The stars slowly come out and the Southern Hemisphere constellations brilliantly shine beneath the sweep of the Milky Way.

 

by Ellen Gray / WALVIS BAY, NAMIBIA /

The ORACLES science team is in southern Africa to fly.

The bulk of their work is done in the narrow confines of the stocky P-3 aircraft amid racks of customized instruments. In the coming weeks these instruments will be complemented by remote sensors on the high-altitude ER-2 aircraft. But while the ER-2 team waits for the arrival of their specialized fuel, the science flight on September 2 is all P-3.

For this 8:00 a.m. flight, wake up time is early but you wouldn’t know it for the palpable sense of excitement the scientists have as they board the plane. This is the first “flight of opportunity;” the theme: It’s Positively Radiant Research. The flight will focus on the energy balance of the clouds over the ocean: how much light are clouds reflecting or absorbing as they interact with the smoke aerosols that travel from agricultural fires in central Africa.

The inside of the P-3 looks like a laboratory with big boxy instruments in front of airline seats. Twenty-four scientists can fly at a time with more than a dozen instruments. Once everyone’s aboard, ears safely covered by noise-cancelling headphones, the turboprop engines fire up. The P-3 taxis down the runway and takes off.

This is a LOUD plane – deafening, in fact. The headsets have the dual role of hearing protection and allowing everyone on board to communicate, reporting real-time observations. Sebastian Schmidt of the University of Colorado, Boulder is the flight scientist  today. Sitting up front, his is the single voice speaking to the pilots, relaying any requests for adjustments in the flight path that come from the instrument teams.

The pilots, Mike Singer and Mark Russell of NASA’s Wallops Flight Facility, have final say on the flight path. They are responsible for the safety of the plane and its occupants. With hundreds of science flight hours under their belts, they’re very familiar with how scientists like to fly. Today it’s in tight spirals from the top of the smoke layer and clouds to near the ocean surface to see what the air is doing along a vertical column.

On this eight-hour flight, though, the science team channel isn’t all business. “Who still needs a nickname?” Sam LeBlanc of NASA’s Ames Research Center in charge of the 4STAR instrument asked at one point.

A number of the flying scientists apparently still do. Among them, Sabrina Cochrane, a second-year grad student at the University of Colorado, Boulder, manning the Solar Spectral Flux Radiometer. This is her first research flight.

“I was really nervous,” she said after the flight. “I thought I was going to feel sick the whole time with all the spirals, but I didn’t. It was really smooth. It was a lot more fun than I expected.”

Flying between the spiral locations, the Airborne Precipitation Radar team was on the look-out for another high-flyer: the CloudSat satellite in space, which was scheduled to make a pass over the same region the P-3 was flying. This radar measures cloud droplet sizes and numbers, validating the same measurements taken from space by CloudSat’s radar.

The satellite overpass was not exactly over the flight path, but close enough, said Steve Durden of NASA’s Jet Propulsion Laboratory. “Even if they’re not perfectly aligned you’ll see the same structures in the clouds,” he said.

The final maneuvers of the day occur during the last hour of flight on the way back to Walvis Bay Airport. David Noone of Oregon State University explained that these maneuvers are for the instruments, to find out how different orientations of the aircraft affect the measurements.

“My measurements, the water vapor and the water vapor isotope measurements, are a good example of this. We’re bringing in air from outside through an inlet that must be pointing directly forward into the flow. If it’s slightly off, the number of cloud droplets that enter the inlet might vary,” he said.

To test out the orientations the pilots will wiggle the tail of the aircraft, roll side to side, and go up and down like they’re going over a hill.

“Now some of these are good fun,” said Noone, “but we’re sitting here in the back of the aircraft. We’re way out in the tail so we’re going to get a good ride.”

 

 

 

 

 

by Ellen Gray / SWAKOPMUND, NAMIBIA /

Planning a science flight does not appear to be most exciting part of a NASA airborne mission, even from an exotic location like the Namibian coast where we are now for the ORACLES mission. No planes. No high-altitude views. Just a group of people on computers sitting at long tables in a windowless conference room staring intently at a projector screen.

“I couldn’t disagree more that it’s unglamorous,” said ORACLES principal investigator Jens Redemann of NASA’s Ames Research Center. “I am so excited to be here planning the flights. It’s the promise of a great flight, like visualizing the greatest possible outcome. It’s the perfect flight that we’re on the hunt for every time. You don’t think about anything else while you’re flight planning.”

The work they’re doing at this 8:00 a.m. meeting literally drives the mission. The forecasting team shows videos of slow-moving model projections of the clouds and aerosols over central and southern Africa and the Atlantic Ocean all the way out to Ascension Island. Like fishermen discussing where to find the best catch, they discuss in excruciating detail where they think the best clouds and aerosol plumes will be.

Like any other prediction of the future, however, these models are not 100 percent correct all the time.

“We know that models aren’t perfect,” said Karla Longo of the Global Modeling and Assimilation Office at NASA’s Goddard Space Flight Center. The Goddard Earth Observing System or GEOS-5 model, for instance, tends to underestimate low-level clouds in this region.

“We have to use it here though so we understand when and why it’s wrong. People don’t always feel good about it, but it’s the only way to improve,” said Longo.

Part of the forecast briefing is devoted to looking back to the previous flight and comparing the forecast for it with what the plane actually found. Over the coming months and years, the ORACLES measurements will be used to update the physics that drive the model.

Meanwhile the science team is riveted because flawed or not, these are the images they need to plan the next flight.

On an airborne mission like this there’s not a preset plan of where and when they will fly. Planning is done day by day. It’s a balance between the need for aircraft crew rest and the potential for good clouds and aerosol plumes to measure.

“We’re always concerned about low-level clouds and the amount of smoke in the biomass burning plumes,” said Redemann. “The juggling act is that our science objectives are diverse enough that we look for different plume and cloud characteristics on different days.”

After the forecast briefing to plan the flight for Friday, Sept. 2, Redemann gathers around a whiteboard with a few of the instrument scientists to hash out the nitty-gritty details of the main science section of the flight. The focus of Friday’s flight is radiative balance. They will design the flight plan to maximize the measurements taken by the Solar Spectral Flux Radiometer, which gauges the brightness of the clouds to determine the energy – light – in the atmosphere coming from all directions – directly from the sun, filtered through clouds, and reflected by clouds.

“The aerosol plume has a different effect on the radiation balance depending on whether the plume is above smooth or broken clouds,” said Redemann. Aerosols can have either a cooling or a warming effect, depending on the brightness of the clouds below. “We’re trying to verify that experimentally in flight.”

The science planning conversation is long and involves a shorthand language, squiggles on the whiteboard and questions like “Do you want to spiral here?”

Once they figure out the science plan, the pilots come in and work with the team to write their flight plans,  including when and where to fly the aircraft from the cloud tops down to a few hundred feet above the ocean surface in a corkscrew-like spiral.

By the end of the day it all comes together, and all that’s left is for the science teams to decide who gets to fly onboard with their instruments.

 

 

by Ellen Gray / WALVIS BAY, NAMIBIA /

It’s chilly at 6 a.m. at the Walvis Bay Airport on Wednesday, Aug. 31. Only a couple of employees are here, two hours before the usual work day starts, to scan through security the science team for NASA’s ORACLES mission who are getting ready for the first complete science flight.

The airport is less than a year old with commuter flights from across southern Africa. It’s a tiny, two-story terminal, taking barely a minute to walk from one end to the other. It’s waiting area is still shiny and new, with red seats that will be filled by tourists coming and going in a few hours. But for now it is quiet.

On the runway in front of the hangar, the crew of NASA’s P-3 turbo prop aircraft readies it for flight. Today’s flight plan is called “Routine 1b.” “Routine” because the track — northwest from the airport over the Atlantic then turning due west — will be the regular route the team will fly over the next month to measure the low-lying clouds off the coast and the layer of aerosols above, primarily smoke from seasonal agricultural fires in central Africa.

The “1b” is for first flight, second attempt. Tuesday’s attempt at “Routine 1” ran into a minor technical issue with the aircraft half an hour into the flight that caused it to return early to base.

“There’s a real sense of excitement now that we’re here,” said David Noone of Oregon State University, one of the 24 scientists who was aboard the P-3 with an instrument to measure isotopes of water vapor. The water vapor that travels with the aerosols has a different fingerprint than the water in the clouds, and the measurements tell him how the two are mixing.

“We’ve been planning this experiment for three years,” said Noone. “So many people, so many logistics, so many challenges. To be here to start answering these critical science questions that affect future climate is really awesome.”

Aerosols and how they affect clouds are two of the biggest unknowns in climate science. The only way to learn how they work and affect Earth’s energy balance – how much heat sticks on the planet – is to fly through them both.

The P-3 is loud (best wear your ear protection!) when it fires up. Its propellers kick up a cloud of Namibian desert dust as it moves along the runway. At 8:00 a.m., it’s wheels up and they’re off.

Back in Mission Ops, a conference room at the Swakopmund Hotel a good 45-minute drive from the airport, the non-flying ORACLES scientists monitor the flight for the next eight hours. A web page projected on the big screen shows the plane’s location. A chat program allows the Earth-bound team to communicate via satellite with Rob Wood, the ORACLES flight scientist in charge on the P-3.

“This was my first flight on the P-3,” said Wood, ORACLES deputy principal investigator from the University of Washington, Seattle. “I was a little nervous about what I needed to do as flight scientist. It’s a totally new system to me. But the crew worked wonders to make it easy and get me fit into their system.”

After a long seven-and-a-half-hour flight, the whole science team is happy.

“It’s always good to get that first flight under your belt,” said Wood with a big smile on his face. “It’s even better when it’s such an amazing flight. This was up there with the best of my career.”

 

 

 

 

by Ellen Gray / WALVIS BAY, NAMIBIA /

This desert was nothing like what I expected. Flying in to Walvis Bay Airport in Namibia, Africa, unbroken beige stretched as far as I could see out the window, lined with the occasional road and dotted by the occasional black rock outcrop, like islands in the sea.

From the ground at first glance, it’s pretty boring in most directions: big sky and flat sand with little to interrupt the horizon. Until you turn and see what look like orange-ish mountains in the distance. They’re not mountains. They’re dunes. As we drive closer, they keep getting bigger. The Crocodile Dundee voice in my head says “Now, that’s a dune.”

The dunes are the most spectacular feature of the Namib Desert, one of the oldest deserts in the world, that runs the length of the Namibian coast on the western shore of Africa. But it’s the coast – specifically the clouds above the Atlantic Ocean to the west – that have brought a team of NASA and university scientists and two research aircraft to this remote region for a NASA airborne mission: Observation of Aerosols above Clouds and their Interactions (ORACLES).

Offshore are two things that make the coast of Namibia unique in the entire world: a layer of low-lying cumulus clouds and above that a steady layer of smoke particles – a type of aerosol – that are borne westward on the winds from forest and brush fires over central Africa.

Aerosols and how they change the behavior of clouds are one of the biggest mysteries in the climate change puzzle. Do aerosols make clouds thicker? Do they reflect more sunlight, or change how much sunlight clouds reflect? Do they absorb sunlight and make the atmosphere warmer? The lessons learned from flying above and through this “perfect natural laboratory,” as principal investigator Jens Redemann put it, will yield insights into cloud-aerosol interactions around the world.

The same conditions that make the low-lying clouds also make the coast really foggy in the morning. The fog is a reliable source of moisture for the plants that cover rocks and boulders sticking out of the sand. Desert-warmed air condenses over cold ocean water to form a marine layer, similar to the ones seen on the California coast.

We are staying in Swakopmund, a tourist town about 45 minutes from the more industrial city of Walvis Bay. This is a former German colony town founded in 1892, and you can see the influence on the architecture. The town is built out rather than up. A constant breeze blows keeping the late August air a nice 70 to 75 degrees Fahrenheit.

As we drive south toward the airport on our first full day here, we’re between two extremes with the Atlantic ocean out the right window and the desert out the left.

The ocean is blue and huge, and vacation rentals dominate a long section of beach, giving way to a view of offshore drilling platforms in the distance as we near the city of Walvis Bay. Like Swakopmund, the city is spread out, and signs on the highway caution to watch out for children crossing between two residential areas.

At the southern reach of the city new construction is going up as we turn inland toward the desert and the airport.  The dunes in the distance grow until we pass Dune 7, the tallest in the area at over 1200 feet. Out here, under the sun, the temperature will be in the 90s F by midday.

Soon after we arrive at Walvis Bay Airport, a tiny bump on the horizon that will be the ORACLES base of operations for the next month. A spill of scientists, freshly badged for airport access, disembark out of the shuttle van, ready to go.