Operation IceBridge: Antarctic 2014: The Large, the Small, and Statistical Significance

October 27th, 2014 by Nathan Kurtz, Sea Ice Scientist, NASA Goddard Space Flight Center

Gazing out the window of the IceBridge DC-8 aircraft is a bit unsettling. The Antarctic region is a vast and seemingly endless wilderness, and undoubtedly it is a dangerous place without the support of a fantastic array of technology and people. But there’s also a sense of comfort, even superiority, in that the modern wonders of technology and social organization can safely carry us through such forbidding terrain. Terrain that has already claimed the lives of many who have previously attempted to do so with more primitive means. Yet, any sense of superiority and safety is always to some degree an illusion. I’m reminded of the great physicist Richard Feynman who once said, “The first principle is that you must not fool yourself…and you are the easiest person to fool.”

sea ice shadow

The shadow of NASA’s DC-8 on Antarctic sea ice. Credit: NASA / Jim Yungel

With that in mind I am more appreciative of the power of nature and chance which helps to deflate any unnatural sense of superiority and self-importance. But it also brings to mind a paradox, our aircraft is little more than a mere speck to the size of the problem which we are studying, and yet this speck is tasked with carrying out a mission to provide meaningful information on the state of the Antarctic and the global impact of changes to the region.

Consider the scale of the problem: the Antarctic ice sheet is more than 5 million square miles and the surrounding sea ice reached an extent of 7.8 million square miles this past September. As a rough estimate, the IceBridge dataset will cover some 20,000 square miles, while this is quite large, it is still a mere fraction of a percent of the total area of Antarctica and the surrounding seas. This large difference in scale underscores one very difficult nature of the problem and illustrates the main reason I personally feel quite small in the face of something so immense.

Undoubtedly the Antarctic is seen as important to consider as a topic of interest beyond certain specialized branches of science. The Antarctic ice sheet has the potential to raise sea level by over 200 feet were it to melt in entirety, a number which carries significance to the large numbers of people living in coastal regions. Antarctic sea ice is an important regulator of the global temperature since it reflects a large portion of solar radiation back to space which helps to lower the mean global temperature. It also influences the deep ocean circulation allowing higher forms of life to thrive even at the greatest depths.

aboard the dc-8

Researchers aboard NASA’s DC-8 during an IceBridge survey flight. Credit: NASA / Michael Studinger

Acknowledgment of powerful factors such as these has captured the attention of a broad swath of people and was aptly demonstrated this past year with the release of two major stories by the media concerning changes in the Antarctic. The front page of the New York Times rang out “Scientists Warn of Rising Oceans From Polar Melt”. This story, (which IceBridge data played a role) was in reference to recent findings that the West Antarctic Ice Sheet is now in an irreversible decline to take place over the course of the next thousand years or so.

A second widely circulated story was on the observation that Antarctic sea ice had reached the highest extent ever observed in the satellite era this past September, a counter-intuitive phenomenon that superficially defies conventional expectations on what a warming climate should do to polar ice. Though it does have, in fact, a rational physical explanation, it is currently the subject of much scientific inquiry due to the complexity of factors involved.

Thus, this brings to my mind a sense of uncertainty that overwhelmingly powerful forces of nature are in control – despite our great technological capability – and yet it is our technological capability which allows us to see this on a grand scale. But the lack of control brings to mind doubt, how can we be so clever to see large forces at work and yet also be powerless to change a potentially negative course of action? This sense of doubt and uncertainty casts a long shadow, a shadow which also has bearing on the IceBridge mission. In essence, it comes from recognition of the fact that science is not perfect, and claims to the absolute validity of anything should be taken with doubt.

Shackleton Range

Mountains of Antarctica’s Shackleton Range seen from the DC-8 on the Oct. 25, 2014, IceBridge survey flight. Credit: NASA / Jim Yungel

The existence of doubt is paramount to how the scientific method works, in that ideas are questioned and tested. In another sense, a lack of doubt and skepticism is also harmful, for as Voltaire says “Those who can make you believe absurdities can make you commit atrocities.” It is exactly this type of doubt that sows mistrust, skepticism and at worst nihilism – that everything is too doubtful and meaningless, that the scales are too large and our measurements too small and uncertain. Essentially, a new paradox arises in that doubt and skepticism are necessary yet are harmful at the same time if not properly balanced.

The scientific process has a remedy for this in the use of numbers to bring order to chaotic processes which may seem otherwise too difficult to grasp. Numbers are a unique invention which allows us to unite the grand scale to the small scale at which we make actual observations.

As an example, IceBridge took measurements of surface elevation over a circle centered at 88 degrees latitude. This is useful for both the CryoSat-2 and ICESat-2 satellites because their orbits take them across this region every revolution. On a broad scale, it is thought this is a useful target area because it is located on a part of the polar plateau which is not expected to change significantly in time.

south pole station from above

An overhead view of Amundsen-Scott Station at the South Pole captured by the Digital Mapping System cameras aboard the NASA DC-8. Credit: NASA / DMS Team

But looking out on the surface from the plane revealed a chaotic surface of ridges called sastrugi that are shaped by the howling winds blowing over the surface. Yet features such as these can be described in a simple numeric that distills the visual chaos into something more understandable. This then allows comparisons between different measurements at different spatial scales and times. That is, a point measurement may by itself may convey little information, but brought together in the form of a number (for ICESat-2 this is in the form of a mean difference or bias) it can be compared to a greater whole.

However, numbers can be misleading if cherry-picked to support a particular position. The descent into hair-splitting sophistry and (at heart) overly-emotional polemics so prevalent in many public forums today is evidence of this at work. This leads me to my final question, can numbers alone convey the truth such that their meaning is appropriately acted upon? Or does the associated ability to manipulate numbers to promote a subjective “truth” negate this? Perhaps what is needed to reconcile this dilemma is integrity, which derives from the Latin root “integer” meaning whole or undivided, and is perhaps not incidentally also a specific type of special numbers in mathematics. That is, if one can provide numbers, and do so with integrity, one can then have conviction such that the truth emerges, can gain acceptance, and be acted upon in a meaningful way. Yet even here it is wise to beware that this is some panacea which will solve all these complex problems.

In my opinion providing numbers is a step, at least the only way I personally can attempt to reconcile the large and small scales which have confronted me. As I prepare to head back home to begin working on data from past missions, I have hope that the seemingly small contributions of myself and the crew, engineers, and other scientists will provide some connection to be statistically significant at a much larger scale.

Hurricane and Severe Storm Sentinel (HS3) 2014: Third Flight over Hurricane Gonzalo Completed

October 19th, 2014 by Mary Morris
The WB-57 prepares for takeoff on Friday, October 17th, 2014 from MacDill Air Force Base.

The WB-57 prepares for takeoff on Friday, October 17th, 2014 from MacDill Air Force Base.

On Friday morning, at 7:40 AM EDT, our WB-57 took off for a third, and final flight over Hurricane Gonzalo. At the time of our flight, Gonzalo was a Category 3 storm located south of Bermuda. While we were flying Gonzalo, one of the NOAA P-3s was also investigating Gonzalo. The data the P-3 collected will be particularly useful for the WB-57 instrument teams to validate our results. For example, HIRad is very similar to the Stepped Frequency Microwave Radiometer (SFMR) onboard the NOAA P-3. We can use SFMR data that is collocated with HIRad data to validate our results over the coming weeks.

Members of the instrument teams wait for the WB-57 to taxi back to the hangar after the third science flight over Hurricane Gonzalo.

Members of the instrument teams wait for the WB-57 to taxi back to the hangar after the third science flight over Hurricane Gonzalo.

We still have through the end of October for science flights, so the forecasting team is looking for the next target we can fly over. The National Hurricane Center has given a disturbance in the Gulf of Mexico, related to Tropical Storm Trudy, a medium chance of tropical cyclone formation in the next five days. There is still a lot of uncertainty in the forecast, but it’s worth keeping an eye on the Gulf next week. We always stay prepared for flights on the off chance that something turns out to be a better target for us than originally forecast. Stay tuned!

The folks at the NOAA aircraft operations center were kind enough to share some space with us for the few days we were based out of MacDill. Here, I am, exhilarated after three long, but successful, days of science flights.

The folks at the NOAA aircraft operations center were kind enough to share some space with us for the few days we were based out of MacDill. Here, I am, exhilarated after three long, but successful, days of science flights.

Hurricane and Severe Storm Sentinel (HS3) 2014: Hurricane Gonzalo: The Hunt for Data Continues

October 16th, 2014 by Mary Morris
The WB-57 crews and pilots prepare for take-off from MacDill Air Force Base on October 16, 2014

The WB-57 crews and pilots prepare for take-off from MacDill Air Force Base on October 16, 2014

Today was another interesting day here at MacDill. Our WB-57 took off around 11:16 EDT for Hurricane Gonzalo. During the science flight, Gonzalo’s maximum sustained winds were 145 mph as it continued on its track towards Bermuda. During the ~6 hour mission we were able to cross over the eye three times.

Based on satellite imagery, it looks like the flight planners did a good job at nailing the eye crossings. The team here spends a lot of time planning out coordinates in advance in order to create flight tracks that will give us the best view of the storm. It’s not as simple as just forecasting the center position of the hurricane because we also have to consider the other parts of the hurricane environment that we want to study. All the instrument teams have preferences for the types of data they want to get, but in the end we need to compromise and find a track that works for everyone.  Today’s track put us in a good position to look at the inner core of the storm as well as upper level outflow. We cannot wait to get a look at the processed data to see how well the flight track worked out.

Sitting under the WB-57, I hide from the hot Florida sun and download HIRad data from today’s flight.

Sitting under the WB-57, I hide from the hot Florida sun and download HIRad data from today’s flight.

The plan for tomorrow is to get one last flight over Hurricane Gonzalo, but we’ll have to get an early start, taking off at 7am, in order to make the most out of the WB-57’s range. Due to range limitations, we will probably only get two passes over the eye this time, but it’s better than nothing. After tomorrow’s flight, the researchers will head back to their respective homes until we find a new suitable target to fly over.

After a second successful flight over Hurricane Gonzalo, crews prepare the WB-57 for the next flight from MacDill Air Force Base.

After a second successful flight over Hurricane Gonzalo, crews prepare the WB-57 for the next flight from MacDill Air Force Base.

Hurricane and Severe Storm Sentinel (HS3) 2014: Science Flights over Hurricane Gonzalo Begin

October 15th, 2014 by Mary Morris
Maintenance crews and the pilots prepare for departure from MacDill Air Force base on October 15, 2015

Maintenance crews and the pilots prepare for departure from MacDill Air Force base on October 15, 2015

HS3 UAV flights officially ended a couple of weeks ago, but there has been a successful extension of the HS3 mission through a new NASA/Navy collaboration. Two instruments from HS3 that didn’t get to fly this hurricane season due to aircraft issues, HIRad and HIWRAP, are now loaded onto a manned WB-57 and will be flying over storms through the end of October.

Members of the team collaborate as they launch dropsondes into Hurricane Gonzalo during a science flight on October 15, 2014

Members of the team collaborate as they launch dropsondes into Hurricane Gonzalo during a science flight on October 15, 2014

Things are looking up for the HIRad and HIWRAP teams, as we just finished our first successful science flight over Hurricane Gonzalo today. Hurricane Gonzalo is undergoing an eyewall replacement cycle and has a maximum sustained wind of 125 miles per hour. Headed towards Bermuda, Gonzalo is expected to maintain its major hurricane status through Friday. Luckily, Gonzalo is in range of the WB-57, which will be based out of the MacDill Air Force base in Tampa, FL through Friday. The team here is working hard to get as much data as possible. Stay tuned!

The WB-57 lands after completing its first science flight at MacDill Air Force base on October 15, 2015

The WB-57 lands after completing its first science flight at MacDill Air Force base on October 15, 2015

 

NASA in Alaska 2014: More Flying with ARISE

October 8th, 2014 by Michal Segal Rozenhaimer

image12

Editor’s note: The following is a first-hand account of ARISE survey flights by one of the mission’s researchers. To see the first two days’ accounts, visit:
http://earthobservatory.nasa.gov/blogs/fromthefield/2014/09/17/flying-with-arise/

Day 3 (Sept. 16, 2014)

Today was a long flight day. It started off by trying to guess where the high clouds (i.e. cirrus) will move in. We had to choose between three options, and our choice turned out to be a good bet. We flew to the edge of the sea ice to try to characterize both its exact mapping and see whether the clouds look different or have different characteristics, height and composition (i.e. water and ice) above the sea-ice versus open ocean. We had a mix of high clouds above ice but also clear regions, with black and white ice, as seen in the pictures. The sun was posing for us and we got to see some halo forming around the sun. This means that we had ice clouds (cirrostratus) with particular ice shapes of smooth hexagonal crystals are reflecting and refracting the sun rays to form this circle of light surrounding the sun.

image14

Day 4 (Sept. 18, 2014)

Today was a challenging day. We were after clouds, and oh, they are “hard-to-get” into a specific posture. We flew high to check the area and had a gorgeous stratus deck below us. The word stratus in Latin means “spread out” and boy, they were spread out all right.

At some point we saw an opportunity to dive below the clouds,  and cruising over the broken sea-ice, we felt like we were in a Star Trek episode.

Clouds are so diverse and changeable, so we want to sample them as often as possible to get a feel for their heights, thicknesses and what type of particles they include (water, ice or a mixture of both). This is important because their location in the atmosphere (how high or low they are) and their composition dictates the amount of radiation they absorb or scatter back into space and how they affect the surface below, either warming or cooling. This was a challenging and bumpy flight from all perspectives, but all in all it ended well.

image11

Summary

We had many more flights, some I flew myself, some were flown by my 4STAR team fellows. All flights were magnificent in that they covered pristine sea ice regions, where human access is difficult and low and high clouds over these regions (especially at this time of year) means even the satellites often cannot take measurements. We had some weather and technical hurdles some days, but we succeeded in most of our goals, which were to measure sea-ice formation and state, study sunlight and thermal energy over the sea-ice and open ocean, and characterize cloud spread and type in this complex and important region.

Our final science flight was on Oct. 2, and was dedicated to instrument calibration. It lasted for almost nine hours and ended after sunset, since some of the instruments (including our own SUN-photometer) needed to be calibrated by the sun, looking at the wide range of sunlight intensity during sunrise or sunset period. We flew over some dormant volcanos in the southern part of Alaska, over glaciers and Denali park. What a great finale to a great campaign! Looking forward for next year’s one already.

image13

Notes from the Field