NASA has been tracking Florence since it began moving toward the East Coast of the United States and continued to monitor the storm as it inched across the Carolinas and farther inland. The space agency is sparing no available resource in working to keep disaster responders and agencies such as FEMA and the National Guard informed with the latest information to assist in decisions on everything from evacuations to supply routes and recovery estimates.
Here’s a snapshot of some of the ways NASA has been monitoring the storm and its repercussions:
LAND, ATMOSPHERE NEAR REAL-TIME CAPABILITY FOR EOS
NASA’s Land, Atmosphere Near real-time Capability for EOS (Earth Observing System) (LANCE) provides data and imagery from Terra, Aqua, Aura, Suomi NPP, and GCOM-W1 satellites in less than three hours from satellite observation to meet the needs of the near real-time applications community. LANCE leverages existing satellite data processing systems in order to provide such products from select EOS instruments. These data meet the timely needs of applications such as numerical weather and climate prediction, forecasting and monitoring natural hazards, agriculture, air quality, and disaster relief.
ARIA FLOOD EXTENT MAPS
The Advanced Rapid Imaging and Analysis (ARIA) team at NASA’s Jet Propulsion Laboratory in Pasadena, California, created a flood extent map from Sentinel-1 synthetic aperture radar data acquired 12 hours after Hurricane Florence made landfall. The map, which was pushed to FEMA’s SFTP server (and is available to download), depicts areas of the Carolinas in light blue pixels that are likely flooded.
Media reports provided anecdotal preliminary validation. This map was cross-validated with ARIA’s earlier flood proxy map. This flood proxy map should be used as guidance to identify areas that are likely flooded, and may be less reliable over urban and vegetated areas.
To overcome that limitation, NASA’s Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) instrument aboard NASA’s C-20A aircraft is slated to fly over flooded areas to validate and improve these maps as well as provide near real-time imagery to assist local, state and federal partners.
For example, barrier islands and the immediate coastlines have borne the brunt of the storm surge and wind damage, resulting in the destruction of property along the coastline. UAVSAR imagery will help to clarify areas that have been impacted. Rapid acquisition of UAVSAR imagery revealing damaged homes and infrastructure provides higher spatial resolution details to complement “damage proxy maps” and other change detection approaches applied from routinely collected imagery or special collections from international partners.
VISIBLE INFRARED IMAGING RADIOMETER SUITE
The Day/Night Band sensor of the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi-National Polar-orbiting Partnership and Joint Polar Satellite System satellite platforms (both NOAA partnerships) provide global daily measurements of nocturnal visible and near-infrared light. The VIIRS Black Marble product suite detects light in a range of wavelengths from green to near-infrared, including city lights and lights from other activity.
On September 14, 2018 North Carolina officials said the number of power outages due to Florence was more than half a million. The NASA Black Marble product suite has been used to assess disruptions in energy infrastructure and utility services following major disasters. The night-time imageries are useful for pre-event and post-event mapping and monitoring of power outages in cloud-free conditions.
Satellites make weather monitoring possible
NASA relies heavily on its fleet of Earth-orbiting satellites as well as satellites from partner institutions for data that feeds into critical weather and climate models. Below is a summary of a few of those assets:
ATMOSPHERIC INFRARED SOUNDER
Aboard the Aqua satellite, the agency’s Atmospheric Infrared Sounder (AIRS), in conjunction with the Advanced Microwave Sounding Unit (AMSU), was able to capture three-dimensional images of the storm’s approach by sensing emitted microwave and infrared radiation. Warm colors in the infrared image (red, orange, yellow) show areas with little cloud cover, while cold colors (blue, purple) show areas covered by clouds at high, cold altitudes. The darker the color, the colder and higher the clouds and the stronger the thunderstorms. In partnership with the National Oceanic and Atmospheric Administration, these atmospheric observations are assimilated into operational prediction centers around the world to improve hurricane path prediction and other forecasts.
MODERATE RESOLUTION IMAGING SPECTRORADIOMETER & CLOUDSAT
Another powerful instrument aboard the Aqua satellite (the same instrument is also aboard Aqua’s “twin” satellite, Terra) is the Moderate Resolution Imaging Spectroradiometer (MODIS). Aqua and Terra work in tandem to image the entire globe once every one to two days, which allows MODIS to capture a sweeping picture of any number of Earth dynamics, including storms, through its 36 spectral bands, or groups of wavelengths.
Here, a MODIS image of Florence is shown with a cross-section of the storm taken on the same day by NASA’s Cloudsat satellite. The CloudSat pass offers a unique view of Florence’s asymmetrical structure, the intense convection and rainfall churning inside the storm, and a complex vertical cloud structure that is not visible from above. The storm’s clouds reached an altitude of about 15 kilometers (9 miles) at their highest point—fairly high for a tropical cyclone. The darkest blues represent areas where clouds and raindrops reflected the strongest signal back to the satellite radar. These areas had the heaviest precipitation and the largest water droplets. The blue horizontal line across the data is the melting level; ice particles were present above it, raindrops below it.
MULTI-ANGLE IMAGING SPECTRORADIOMETER
Global multi-angle imagery of the sunlit Earth is the specialty of the Multi-angle Imaging Spectroradiometer (MISR) aboard NASA’s Terra satellite. The instrument takes seven minutes to capture images from all nine of its cameras to observe the same location. MISR can reveal areas of high cloud cover associated with strong thunderstorms as well as spot powerful outer rain bands, which can sometimes spawn tornadoes.
SOIL MOISTURE ACTIVE PASSIVE
Managed by the Jet Propulsion Laboraty in Pasadena, California, and in coordination with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the polar-orbiting Soil Moisture Active Passive (SMAP) satellite plays a key role in forecasting flooding conditions. SMAP measures the amount of water in the top 5 centimeters (2 inches) of soil everywhere on Earth’s surface every 2 to 3 days. This permits changes of soil moisture around the world to be observed over time scales ranging from the life cycles of major storms to repeated measurements of changes over entire seasons. SMAP is also capable of estimating wind speeds over the ocean, as shown in the image above.
INTERNATIONAL SPACE STATION ASSIST
Astronauts aboard the International Space Station (ISS) have been snapping images of Florence with handheld digital cameras throughout the storm’s progression. Once the storm has passed and cloud cover lessens, requests to document flooding and changes to the land surface will be sent to the crew as part of ongoing NASA ISS response to the International Disaster Charter activation for Hurricane Florence. Imagery of this type is then georeferenced by the Earth Science and Remote Sensing Unit at NASA’s Johnson Space Center in Houston.
Also aboard the ISS is the Lightning Imaging Sensor (LIS), which detects the distribution and variability of total lightning day and night in order to improve severe weather forecasting and further scientific study on the relationship between lightning, clouds, and precipitation. Over a 12-hour period, LIS observed an average of more than 5 lightning flashes every 90 seconds in the vicinity of Hurricane Florence on September 14, 2018.
This piece was originally published on NASA's Disaster Response blog.
Kulusuk Island is breathtakingly beautiful — a spectacular mountain backdrop, quaint village, turquoise icebergs, even adorable sled-dog puppies. But Oceans Melting Greenland Project Manager Steve Dinardo didn’t choose it as a base because of the scenery. “We came here to work,” he says.
Kulusuk is ideally located for surveying East Greenland, which the locals call the wild side of the island — even more remote and unpopulated than the west coast. But the weather changes quickly, and the little airport doesn’t have a hangar to protect the research plane. If you have any trouble here, you could be stuck for quite a while. Every day in the field is expensive, and winter is just around the corner.
So the five OMG team members push themselves to get as much done as possible each day.
To begin with, they fly as many hours as they legally can to collect data. After the plane lands, there are still hours of work ahead. The plane is fueled and checked over for the next flight, Steve looks at multiple weather forecasting models to create a forecast for Kulusuk and the probe-drop areas, and Principal Investigator Josh Willis comes up with science priorities to match the weather. Both may end up revising their plans multiple times before the next morning’s fly/no fly decision.
Add to this list trying to stay in touch with family at home, answering a few pressing emails, eating, showering and so on. No wonder that some days, the team gets no more than a few glimpses of the incredible landscape out of plane and hotel windows.
“It’s more of an adventure in retrospect,” Josh summarized. “While you’re there, you have your head down and you’re working as hard as you can. When you get a day off, you sleep.”
The team has already had the one mandatory day off that it will get in Kulusuk. As far as I could tell, everyone filled it almost as full as the work days. At dinner, several team members did mention a nap, but they also spent some of their precious free time out in the Arctic landscape. Jakob Ipsen, manager of the Hotel Kulusuk, found a villager to take senior pilot Andy Ferguson fishing and another who took four of us to see a nearby glacier. Later, Jakob drove a few team members to the highest point on the island to watch the sunset.
The next morning, it was back to business. Steve gave a favorable weather forecast at 7 a.m., and the team took off for another eight-hour research flight about an hour later. They flew north to Scoresby Sund and dropped another 10 probes in key fjords, for a total of 99 drops in five days. Only 150 more to go.
After years of intensive research on Greenland’s glaciers, Josh Willis is standing next to one for the first time in his life. Apusiaajik isn’t one of Greenland’s giants — in fact, its name means “little glacier.” But its marbled blue-and-white wall of ice is tall, long and, as Willis says, majestic.
It’s also melting. From time to time there’s a loud cracking noise, and seconds later, a few refrigerator-sized chunks of ice drop into the ocean. You can’t help wondering when a larger chunk will fall, and how much icy water will hit you when it does. It’s natural for glaciers to lose ice this way, though disconcerting when you’re in the neighborhood. But Apusiaajik is like most of Greenland’s glaciers, it’s out of balance — melting faster than it can be replenished by winter snowfall.
We’re visiting the little glacier on a down day for NASA’s Oceans Melting Greenland (OMG) campaign. It’s close to Kulusuk, a tiny village on Greenland’s east coast that happens to have an airport with a 4,000-foot-long gravel runway. That’s too short for a big jet to take off and land. But for OMG’s converted DC-3, the Kulusuk airport is perfectly located for the mission’s survey flights around southeastern Greenland, studying how ocean water is affecting glaciers like Apusiaajik.
OMG is on its third annual campaign out of a planned five. The goal each year is to blanket Greenland’s continental shelf with probes measuring the seawater’s temperature and salinity. This year, the team has already dropped 89 out of 250 probes, starting at the southern tip of Greenland and working up the east coast. Soon it’ll be time to move north to the next base.
Halfway through OMG’s expected lifespan, what have scientists learned, and what do they still hope to find out?
“We’re beginning to see the signs of long-term changes on Greenland’s continental shelf — changes that take years to happen,” Willis says. “We’ve never seen that before.” Daily changes in water temperature come and go, but the OMG scientists are finding that glaciers react more strongly to slow changes in water temperature far below the ocean surface.
Greenland’s continental shelf is shallow, averaging about 1,600 feet (500 meters) deep. But it’s gashed by troughs carved by ancient glaciers, which can be two times deeper than that. These troughs are natural conduits for deep water to get up on the shelf, but it’s not an easy passage. Sills and underwater mountains within the troughs impede the flow and create basins.
Willis gestures at the ice-flecked channel flowing past Apusiaajik. “In a couple of weeks, all this water will be way downstream,” he says. “In the troughs and basins on the shelf, that’s not true. They’re almost like tide pools — the water comes in at high tide and stays there till the tide comes back. In those deep basins, instead of twice per day like the tide, it’s more like once per year and sometimes less. And when warm or cold water gets in, it stays for years.” There’s not always enough variation in the seawater from winter or summer for water to get into the basins each year; it may take a change in a large-scale ocean climate pattern, similar to an El Niño event in the Pacific Ocean, to trigger the change.
For the last two years, the North Atlantic has been moving into a naturally cooler climate phase. Willis is eager to see when and how far the cooler water will move up the West Greenland coast, and how long it will last.
Answering those questions will chip away at the big remaining goal of OMG: quantifying how much glacial ice melt will result from any given change in ocean temperature. If water comes onto the continental shelf that’s a degree Celsius warmer than now, how much will the melt rate increase? What about three degrees?
“One of the advantages of watching a glacier change year after year after year is that you begin to get an idea of what’s driving the change. If it’s the ocean, I think we’ll be able to quantify that with two more years of OMG data,” Willis says.
“That’s what we set out to do. What I’m really excited about is that it’s beginning to happen.”
"There is a fifth dimension beyond that which is known to man. It is the middle ground between light and shadow. It is an area, which we call, the Twilight Zone."
Like many kids growing up in the 1960s, I eagerly anticipated every episode of a black-and-white TV series by Rod Serling, expecting to be surprised, maybe even a little scared, of the mysteries of that fifth dimension he called “The Twilight Zone.” Little did I know that decades later as an oceanographer, I’d find myself at sea with over 60 like-minded scientists on a program specifically targeting the mysteries of another twilight zone—the one in the ocean that lies just below the sunlit surface.
What motivates us is the need to learn more about the role of the twilight zone and the animals that live there in regulating Earth’s climate. The story of how they do this actually starts at the surface, where microscopic marine algae, or phytoplankton, turn carbon dioxide in the water into organic matter via photosynthesis, much like plants on land.
This organic matter forms the base of the marine food web, which basically means that these microscopic plants serve as food for tiny marine animals called zooplankton, which are eaten by larger marine organisms and so on up to larger animals, like the fish that humans consume. Many of these animals come up from the twilight zone at night, using the cover of darkness to feed in surface waters and then disappear come daybreak. This is, in fact, the largest animal migration on Earth and happens around the globe every day, and we barely know it happens.
But I am getting ahead of myself, because despite how appropriate Rod Serling’s description of the mysteries of “the middle ground between light and shadow” fits with what we are doing out here, peering with our instruments into the dimly lit depths, his TV show is not the origin of the name of a twilight zone in ocean sciences. In fact, at least as far back as 1915, textbooks included discussion of the “decrease in the abundance of life from the sunlit surface layers, through the twilight zone, to the zone of darkness,” as was written in College Physiography.
Getting back to this cruise, most of the carbon either sinks out of the surface ocean directly or is carried by animals back down to the twilight zone in their guts and gets excreted. All of this sinking carbon becomes food for other twilight zone animals, with less and less remaining as you go deeper. This constant rain of organic carbon is known as “marine snow,” which drifts through the twilight zone and into the deep ocean.
Who cares how much organic matter or carbon goes through the twilight zone? Well, if you are an animal living in the twilight zone, that’s your main food supply. As a human concerned with the potential for rising carbon dioxide levels in the atmosphere to disrupt our climate, it’s the quickest way you can get organic carbon to the deep ocean, effectively removing it from contact with the surface ocean and atmosphere for hundreds or thousands of years.
Simply put, without the ocean storing carbon in the deep sea, the levels of carbon dioxide in the atmosphere would be much higher than they are today. And the last time they were this high, Earth was a much different place.
The tools I used to measure this cascade of particles carrying organic carbon to depth on this voyage include sediment traps—something like a rain gauge that captures in a tube the sinking particles that are slowly settling through the water. A second method my group uses to measure sinking particles takes advantage of a naturally occurring element called thorium-234, which is slightly radioactive and decays with a precise 24.1-day half-life. This clock allows me to calculate very precisely how much carbon is being carried from the surface through the twilight zone.
It’s far too early to share my results from this cruise, but the importance and complexity of these links between twilight zone organisms and climate should not be underestimated. Like snowfall on land, organic carbon transport to the depths varies with the seasons and locations in the oceans, but in ways we cannot predict. And it is important for us in our efforts to better understand how quickly climate will change as we keep adding more carbon dioxide to the atmosphere. This job is so complex that it takes a village out here aboard two research ships, with autonomous vehicles in the water and support teams on land and satellites above. We work together to study these carbon flows and the living organisms in the twilight zone that create what marine biologist and conservationist Rachel Carson called the “most stupendous snowfall on earth.”
I don’t know if there are any episodes of The Twilight Zone to watch out here, but I do know there are many deeper mysteries we hope to unravel about the ocean’s twilight zone.
Ken Buesseler is a senior scientist at the Woods Hole Oceanographic Institution. He has been working for decades on the ocean twilight zone and its impact on Earth’s carbon cycle. He is currently on the R/V Roger Revelle as part of the Export Processes in the Ocean from Remote Sensing (EXPORTS) field campaign.
This piece was originally published on the NASA Earth Expeditions blog.
I am Dave Siegel, a professor of marine science at the University of California, Santa Barbara. I have been working for many years to implement the Export Processes in the Ocean from Remote Sensing (EXPORTS) oceanographic campaign: a coordinated field effort to understand the interactions between life in the sea and Earth’s carbon cycle.
Last Thursday night, I watched “my baby” of a campaign sail away, as the Research Vessel Sally Ride left Pier 91 in Seattle for the northeastern Pacific Ocean.
While I am the science lead for EXPORTS, it’s not just my baby—it is truly a group effort. Two teams of scientists created the EXPORTS science and implementation plans, with a lot of input from the greater oceanographic community. The result is a campaign comprising more than 50 funded NASA and NSF investigators from nearly 30 institutions and many graduate students, postdocs and technicians, all excellently supported by the masters and crews of two Scripps Institution of Oceanography’s research vessels: the R/V Roger Revelle and the R/V Sally Ride.
EXPORTS aims to develop a predictive understanding of the interactions of life in the sea and Earth’s carbon cycle, which is critical for quantifying the carbon storage capacity of the global ocean. The oceans are Earth’s largest active reservoir, or storage, of carbon and carbon dioxide concentrations in the atmosphere and thus helps regulate our planet’s climate. This predictive understanding of the interactions of ocean life and the carbon cycle is especially important as we are seeing that our ocean ecosystems are changing in response to changes in Earth’s physical climate. To do this we need data to test and validate these satellite-based assessments and numerical model predictions.
We are trying to tackle a super hard problem—one I believe to be a true grand challenge in Earth System Science. Our approach is simply to follow the money. For ocean ecosystems, that currency is the energy stored in phytoplankton carbon from photosynthesis. The production of phytoplankton carbon is nearly balanced by its consumption by animals called zooplankton, which in turn provide the energy for the higher trophic levels of the sea, such as fisheries and charismatic megafauna (whales, seals, sharks, and the like).
The slight imbalance—roughly 10 percent of phytoplankton production globally—drives an export of organic carbon from the well-lit surface ocean into the dimly-lit twilight zone beneath. Within the twilight zone, microbes and animals of all description consume this exported organic carbon, utilizing their energy for metabolism. This export of organic carbon from the upper ocean and their consumption within the twilight zone, along with ocean circulation, shape the carbon storage capacity of the global ocean and frame the two major research questions for EXPORTS.
Constructing a field campaign to identify and quantify the flows of organic carbon through the ocean is, of course, a major challenge. Phytoplankton physiologists need to assess phytoplankton growth rates and responses to perturbations in their required nutrients (nitrogen, phosphate, silica & iron). Zooplankton grazing and the carbon cycle impacts of their daily vertical migration to the sunlit layer of the ocean from the twilight zone need to be assessed.
Sediment traps that catch the rain of sinking particles measure the flux of sinking carbon as well as make detailed geochemical measurements that test how well our measurements of the individual pathways reflect the large-scale mass budgets needed to build and test satellite and computational models. Optical oceanographers make ocean color measurements that link the EXPORTS datasets to NASA satellite data products. And I feel bad that I left out so many other individual research activities going on, but mentioning each of them would take up another two paragraphs!
The measurements needed to constrain the various food web and export pathways as well as adequately sample the highly variable ocean environment requires technologists that can overcome these challenges. For example, the EXPORTS team includes robotics experts who build, deploy, and analyze data from an array of autonomous underwater vehicles (AUV) that sample ocean properties on time scales ranging from minute to years.
EXPORTS has also taken advantage of recent technological advances such as novel high-throughput microscopes and in situ imaging devices that take individual images of billions of phytoplankton cells as well as zooplankton and other various organic matter. These images are then analyzed using advanced machine learning techniques to provide unique views of the structure of plankton communities.
Advancements are also available from the biomolecular sciences where metagenomic and bioinformatics approaches provide complementary ways to characterize plankton communities and their metabolism. Lastly, several projects include numerical modelers who will use computational approaches to help answer EXPORTS science questions.
The first EXPORTS field deployment will be to Station P (50N 145W) in the Northeast Subarctic Pacific Ocean. Station P (or PAPA) has been sampled and resampled over many decades—from as far back as 1949, when it served as an ocean weather station. Presently, Station P is the terminus of the Canadian Line P transect ocean research program and is an area of focus for the National Science Foundation’s Ocean Observatories Initiative project.
Last week, the R/V Roger Revelle and the R/V Sally Ride sailed to Station P. Both are floating laboratories that enable our research, but they will have different missions. The R/V Roger Revelle will make detailed rate measurements and conduct a wide variety of experiments while the R/V Sally Ridewill make spatial surveys around its partner ship to assess the three-dimensionality of these processes. These ship-based measurements will be supplemented by the array of AUVs. Both ships and robots will make ocean optical measurements linking the EXPORTS field data to present and future NASA ocean color satellite missions.
EXPORTS is also planning a second field deployment in the North Atlantic Ocean in the spring of 2020 to provide contrasting data. Furthermore, NASA has supported a group of Pre-EXPORTS projects aimed at mining available, relevant data sources for use in EXPORTS synthesis analyses and to conduct modeling experiments to help plan this and the North Atlantic expeditions.
So I’m the science lead but I’m not sailing. Seems weird, but early in our planning we were worried about the coordination between all of the things going on. My job back home now is to help coordinate activities on the two ships and assist the four co-chief scientists in fouling off whatever curveballs that may come. I’m sure they will provide blog posts soon introducing themselves.
It is been a long time coming and I realized that as the R/V Sally Ride was sailing away. I have been there from the start pushing this along, so I suppose it is “my baby.” I do want to thank all involved in the planning and implementation, including the program officers at NASA and NSF.
This piece was originally published on the NASA Earth Expeditions blog.
My name is Arie and I am a 21-year-old student at the University of Denver studying environmental science. I am one of 28 students selected to participate in NASA’s Student Airborne Research Program, or SARP, an eight-week summer internship program that exposes undergraduate students to all aspects of airborne science campaigns, including data collection techniques and data analysis. Students from diverse STEM backgrounds were placed into four research groups—atmospheric chemistry, ocean remote sensing, land remote sensing, and whole air sampling—and they must complete and present a research project by the end of the summer.
I grew up in Lincolnshire, Illinois, and since a young age I have been fascinated by the scientific processes that influence our planet. I believe that every human has the right to live a meaningful and purposeful life predicated on the existence of certain universal guarantees, such as clean air to breathe, safe food and water to eat and drink, and preserved natural areas. Those values align with SARP and almost all other NASA Earth Science campaigns, as their main objective is to collect accurate and high-quality data about the land, ocean, and atmospheric properties of Earth to understand how our world is changing.
For this campaign, we were seated in NASA’s DC-8 flying laboratory, a unique plane with scientific instruments protruding from the windows. NASA’s DC-8 is not like any traditional commercial airline flight. It was once a commercial airliner but was repurposed by NASA’s Earth Science Division and is now one of the best research aircraft in the world for conducting airborne science. Prior to my flight, the aircraft completed flights for NASA’s Atmospheric Tomography Mission (ATom), an around-the-world airborne science campaign dedicated to studying the impact of human-produced air pollution on greenhouse gases and on chemically reactive gases in the atmosphere.
On this particular flight, we had instruments that measured the presence and relative concentrations of important atmospheric gases over regions in southern and central California, including the San Joaquin Valley. I could hear the faint crescendo of the aircraft’s engine and full-blast air conditioning system through my noise-canceling headphones. The scientists, flight engineers, and pilot talked over the on-board communication system. I listened intently to the scientists as they updated the crew on their instruments.
The aircraft flight path and maneuvers depend on the goals of a particular scientific mission. On this six-hour flight, we undertook spirals, loops, and Meteorological Measurement System (MMS) maneuvers, which are important for understanding the aerodynamics of the aircraft and its effects on measurements such as pressure, winds, and air flow. We also flew in turbulent conditions at various elevations and over diverse environmental gradients.
That being said, it may come as no surprise that my DC-8 flight was as turbulent as it was long; I actually ended up getting pretty motion sick on the mission. Getting sick is a sacrifice some make to collect the necessary data. Despite not feeling well, I was surrounded by passionate students, scientists, engineers, and flight specialists all cumulatively working to advance one of NASA’s core missions: to understand and protect our home planet.
I am excited to see all of the diverse and interesting projects that SARP 2018 will embark and present on at the end of the summer. I couldn’t ask to be in a better place or time here at NASA working with and be mentored by some of the best minds in the field.
This piece was originally published on NASA's Earth Expeditions blog.
Earlier this month, we showed a space-based view of a glory—a colorful, circular optical phenomenon caused by water droplets scattering light. The Moderate Resolution Imaging Spectroradiometer on the Terra and Aqua satellites can see only a cross section of the glory, making it appear in satellite imagery as two elongated bands parallel to the path of the satellite.
To the Earth-bound observer, however, glories take on a circular shape. You might have seen one while on an aircraft. From this perspective, passengers on the side of the plane directly opposite the Sun can sometimes see the plane’s shadow on the clouds below. This position is also where glories can be observed as the cloud’s water droplets scatter sunlight back toward a source of light.
Before aviation, the phenomenon was often seen by mountain climbers; the glory encircling the climber’s shadow on the clouds below. Today, pilots and passengers have a good chance of seeing them, earning the phenomenon the name “glory of the pilot” or “pilot’s halo.”
But you still have to be flying close enough to the cloud deck for the phenomenon to be visible, which is one of the reasons why they are frequently spotted by scientists and crew with NASA’s Operation IceBridge mission. The mission makes annual flights over Earth’s poles to map the ice; flights are relatively low, long, and frequent. Glories are not part of the mission’s science goals—in fact, clouds can interfere with the collection of science data. But they are on the list of natural wonders that IceBridge scientists witness in the field.
Jeremy Harbeck, a sea ice scientist at NASA’s Goddard Space Flight Center, snapped the top photograph of a glory on April 18, 2018, during an IceBridge science flight over the Chukchi Sea. (See the full image and other photographs shot by Harbeck during the Arctic 2018 IceBridge campaign here.)
“I remember having taken more images of glories, especially down over Antarctica, as we see them quite often down there,” Harbeck said. “From what I remember, they’re not outside the window all the time, but you can catch them here and there on flights when conditions are right.”
One such Antarctic glory is visible in the image above, snapped by Michael Studinger during an IceBridge flight on October 26, 2010. Read more about that image here.
This piece was originally published on the NASA Earth Observatory Earth Matters blog.
Hydrologist Matt Rodell at NASA's Goddard Spaceflight Center has been living with first-of-its-kind data from the Gravity Recovery and Climate Experiment (GRACE) for 16 years. That data shows big changes of mass in specific spots on Earth, primarily the result of the movement of water and ice, but it doesn’t tell them what causes those changes. That's where Matt and the GRACE team come in, painstakingly connecting these observed changes to the loss of ice sheets, depleting aquifers, and climate change. It's a problem they're still working on, getting closer every day. Matt explains the years-long process in his own words.
Ominous beginning: Garbage data from a new satellite
Six months after GRACE launched in March 2002, we got our first look at the data fields. They had these big vertical, pole-to-pole stripes that obscured everything. We’re like, holy cow this is garbage. All this work and it’s going to be useless. But it didn’t take the science team long to realize that they could use some pretty common data filters to remove the noise, and after that they were able to clean up the fields and we could see quite a bit more of the signal. We definitely breathed a sigh of relief. Steadily over the course of the mission, the science team became better and better at processing the data, removing errors, and some of the features came into focus. Then it became clear that we could do useful things with it.
And then trends emerged
It only took a couple of years. By 2004, 2005, the science team working on mass changes in the Arctic and Antarctic could see the ice sheet depletion of Greenland and Antarctica. We’d never been able before to get the total mass change of ice being lost. It was always the elevation changes – there’s this much ice, we guess – but this was like wow, this is the real number.
Not long after that we started to see, maybe, that there were some trends on the land, although it’s a little harder on the land because with terrestrial water storage — the groundwater, soil moisture, snow and everything – there’s inter-annual variability, so if you go from a drought one year to wet a couple years later, it will look like you’re gaining all this water, but really, it’s just natural variability.
But by around 2006, there was a pretty clear trend over Northern India. At the GRACE science team meeting, it turned out another group had noticed that as well. We were friendly with them, so we decided to work on it separately. Our research ended up being published in 2009, a couple years after the trends had started to become apparent. By the time we looked at India, we knew that there were other trends around the world. Slowly not just our team but all sorts of teams, all different scientists around the world, were looking at different apparent trends and diagnosing them and trying to decide if they were real and what was causing them.
A world of big blobs of red and blue
I think the map, the global trends map, is the key. By 2010 we were getting the broad-brush outline, and I wanted to tell a story about what is happening in that map. For me the easiest way was to just look at the data around the continents and talk about the major blobs of red or blue that you see and explain each one of them and not worry about what country it’s in or placing it in a climate region or whatever. We can just draw an outline around these big blobs. Water is being gained or lost. The possible explanations are not that difficult to understand. It’s just trying to figure out which one is right.
Not everywhere you see as red or blue on the map is a real trend. It could be natural variability in part of the cycle where freshwater is increasing or decreasing. But some of the blobs were real trends. If it’s lined up in a place where we know that there’s a lot of agriculture, that they’re using a lot of water for irrigation, there’s a good chance it’s a decreasing trend that’s caused by human-induced groundwater depletion.
And then, there's the question: are any of the changes related to climate change? There have been predictions of precipitation changes, that they’re going to get more precipitation in the high latitudes and more precipitation as rain as opposed to snow. Sometimes people say that the wet get wetter and the dry get dryer. That’s not always the case, but we’ve been looking for that sort of thing. These are large-scale features that are observed by a relatively new satellite system and we’re lucky enough to be some of the first to try and explain them.
What kept me up at night
The past couple years when I’d been working the most intensely on the map, the best parts of my time in the office were when I was working on it. Because I’m a lab chief, I spend about half my time on managerial and administrative things. But I love being able to do the science, and in particular this, looking at the GRACE data, trying to diagnose what’s happening, has been very enjoyable and fulfilling. We've been scrutinizing this map going on eight, nine years now, and I really do have a strong connection to it.
What kept me up at night was finding the right explanations and the evidence to support our hypotheses – or evidence to say that this hypothesis is wrong and we need to consider something else. In some cases, you have a strong feeling you know what’s happening but there’s no published paper or data that supports it. Or maybe there is anecdotal evidence or a map that corroborates what you think but is not enough to quantify it. So being able to come up with defendable explanations is what kept me up at night. I knew the reviewers, rightly, couldn’t let us just go and be completely speculative. We have to back up everything we say.
A tangled mix of answers
The world is a complicated place. I think it helped, in the end, that we categorized these changes as natural variability or as a direct human impact or a climate change related impact. But then there can be a mix of those – any of those three can be combined, and when they’re combined, that’s when it’s more difficult to disentangle them and say this one is dominant or whatever. It’s often not obvious. Because these are moving parts and particularly with the natural variability, you know it’s going to take another 15 years, probably the length of the GRACE Follow-On mission, before we become completely confident about some of these. So it’ll be interesting to return to this in 15 years and see which ones we got right and which ones we got wrong.
You can read about Matt’s research here: https://go.nasa.gov/2L7LXoP.
The most important question at the daily briefing for NASA’s Atmospheric Tomography, or ATom, mission is: What are we flying through next?
For the 30 scientists plus aircraft crew loaded up on NASA’s DC-8 flying research laboratory on a 10-flight journey around the world to survey the gases and particles in the atmosphere, knowing what’s ahead isn’t just about avoiding turbulence. It’s also about collecting the best data they can as they travel from the Arctic to the tropics then to the Antarctic and back again.
“ATom is all about the up and downs,” said Paul Newman, lead of the ATom science team and chief scientist for Earth Sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The ups and downs he’s referring to are slow descents from 40,000 feet to 500 feet above the ocean so the researchers aboard can sample the atmosphere at all altitudes in between. That’s not a maneuver the pilots will do if they can’t see what’s below or ahead of them, but the measurements are why the team is out there.
Which is why to find out what they might encounter and safely plan their flight path, it takes a team back home in their offices supporting them with freshly downloaded satellite data, updating forecasting models, an internet connection and phone. The pre-flight briefing takes place at 9 a.m. where the plane is, so for the forecasters calling in from Colorado, Virginia, and Maryland, it often means working late or early to brief the mission scientists and pilots at their hotel. And then when the flight takes off, one of them is in the plane’s private satellite chat room giving them live updates while the plane is in the air.
Weather is of course the big concern. The pilots of the DC-8, which in another life was a mid-sized passenger plane, need to know where the fair and foul weather is.
“Just cutting across the equator, what do you do?” Newman said. “You just fly through those thunderstorms? Or is it better to go west or east around a particular convective cell? You don’t want to get trapped. We don’t want to spend a lot of time flying through a thick cloud. It screws up your measurements, clogs up your air intakes. So with real-time meteorological support, it creates a level of comfort for the team and pilots to know that there won’t be any surprises.”
Weather isn’t the only forecast the team gets before and during the flight. They also get a forecast of the atmospheric chemistry. From supercomputers at Goddard, a computer simulation of Earth projects the paths of carbon monoxide plumes. Carbon monoxide is one of over 400 gases being measured aboard the DC-8, but since it’s the result of incomplete combustion, whether from cars, power plants, wild fires or agricultural fires, it’s one of the simplest for the computer to track. Like a weather forecast, the chemical forecast takes current satellite data of carbon monoxide and then uses winds and temperature to project where it will go into the future – and where the DC-8 aircraft might encounter it on flight day.
“It’s fun to see during the flight whether or not some of these forecasts are realized,” said Julie Nicely of the chemical forecast team. “The person who measures carbon monoxide, for instance, might get on the chat and say, ‘Oh, we just saw CO [carbon monoxide] rise right where you said it would!'” Where turns out to be the easier question to answer. How much of it there is and what other gases occur with and react with it to turn into other gases are much more difficult questions and are among the reasons ATom’s science team is flying through these plumes of pollution.
Carbon monoxide isn’t the only gas whose intermingling with other atmospheric chemistry is being studied. When Nicely’s not supporting ATom she’s researching the hydroxyl radical, a chemical that lasts for a fraction of a second before reacting with other gases in the constantly churning chemistry of the atmosphere. It’s impossible to simulate in the model at the moment, and ATom’s flights are the first time its concentration, along with hundreds of other gases, is being measured on a global scale.
What the science team learns from these flights will go toward not only understanding the chemistry along the strip of the ocean their plane flew over but also improving the atmospheric chemistry models that are a tool for looking at what’s happening across the entire globe.
This piece was originally published on the NASA Earth Expeditions blog.
With springtime comes sunlight and warmth that advance the melting and breakup of Arctic sea ice. Varied patterns and textures appear across the icescape, and many are visible in this image, which was our Image of the Day on April 30. This satellite image includes the area photographed a day earlier by Operation IceBridge—the same photograph that sparked discussion on our blog and on news and social media about what might have caused the holes in the ice.
The holes were not a research focus of the mission; scientists were flying that day to measure the thickness of sea ice. Rather, as some scientists explain below, the holes were simply a sign of spring, and just one of the many interesting and photogenic sights seen from the aircraft in 10 years of research flights over the Arctic.
Nathan Kurtz, IceBridge project scientist
“The main purpose of these IceBridge flights is to measure the thickness of the sea ice. Ice thickness is an important factor which allows us to assess the health of the pack and its ability to survive the summer melt. It is also an important regulator in the exchange of energy and moisture between the ocean and the atmosphere.
“While on the flights, I’ll stare out the windows for hours looking at the surface. The movement of the ice leads to huge variability over small scales, with many interesting scenes and patterns visible and a variety of color shades. But there’s only so much that can be discerned with human eyes. That is why we have the sensitive instrument suite on the plane: to map the intricacies of the ice cover which may otherwise be invisible to us and to quantify parameters for scientific interpretation.”
Chris Shuman, UMBC glaciologist based at NASA’s Goddard Space Flight Center
“Well back into March, satellites show a whole series of relatively clear images over Mackenzie Bay, indicating lots of sunshine coming in. The ‘holes’ in the sea ice are just a sign of spring, augmented by some particular process—’submarine groundwater discharge,’ large mammals, algae growth, brine pockets draining, or something else entirely. Attributing any particular area of open water to a particular process is speculation. There is always a lot going on in the spring sea ice pack of the Beaufort Sea.”
John Sonntag, IceBridge mission scientist
“As scientists, we have the privilege of witnessing the beauty and mystery of the cryosphere firsthand, even as we work to collect that data. The Beaufort 'ice circles' were among those. We have heard a number of plausible explanations for those fascinating features. In a more personal sense, I have been genuinely gratified to see the high level of interest from the public in the ice circles. The public’s clear enthusiasm for the puzzles of nature matches my own. It’s why I like my job!”
This piece was originally published on the NASA Earth Observatory Earth Matters blog.