Dr. Hanwant Singh

NASA Ames Research Center
Co-Mission Scientist for the ARCTAS Project
Palmdale, CA
March 18, 2008

Full bio »

Q: What is ARCTAS?

A: ARCTAS is part of the activities that are going on under the umbrella of the International Polar Year. So there are International Polar Year activities that occur about every 40 or 50 years. But 2008 and 2009 are two of those years when this is occurring after the last ones were in the 50's. So this is where the international community is coming together and focused on polar aspects.

Q: Why study the Arctic?

A: It's generally a very clean region because nobody or very few people actually live there, but there's a lot of pollution that is imported into those areas and transported there. So our main goal is to see how it is getting transported, where it is coming from and what impact it might have to the regional climate in the arctic region, which is also, climatologically, a very sensitive region of the Earth.

Q: Why not use satellites to get this data?

A: The satellites do a good job of staying there for several years so they do provide us a long term view of things, they also cover a lot of territory so they are more global in nature, but they don't do a very good job in terms of the details. They don't measure a lot of things that we need to know in order to understand the system, in order to be able to model it and to forecast or predict the changes in the future. For that we have to depend on aircraft missions and other kinds of things, and so a lot of detailed observations we will be doing using airborne platforms are really not possible from satellites. But there is a second aspect. Things that are measurable from satellites require a lot of validation, because a satellite is really an indirect measure of things, so we will be providing some validation of measurements that the satellites do make.

Dr. Jim Crawford

Program Manager
Tropospheric Chemistry Program for NASA
April 15, 2008

Full bio »

Q: Where did the idea for ARCTAS come from?

A: It was about two and a half years ago that the idea to do something international in terms of IPY was presented to me. And there are a number of different partners that we have in Europe. There's a group in Germany and France and Norway for instance that we've cooperated with in the past, so we tend to do these things in a group. This year we have the Department of Energy and NOAA along with us and on the other side we have the French and the Germans who will again join us in the summer as well.

Q: How does this study relate to climate change?

A: Given the recent loss of Arctic ice in 2007 which was unprecedented, this is a fortuitous time for us to be here looking at climate change in the Arctic. We're particularly interested in the atmospheric contribution to that. And that comes from both gas phase chemistry and particulate chemistry. So in the spring we're looking at what is traditionally been described as Arctic haze. And this Arctic has components that come from pollution transport from mid-latitude locations such as North American, Europe, Asia, Siberia, all those locations all lending some portion of what's found up here in the Arctic this time of year.

Q: So, are you looking at how CO2 is related to climate change?

A: We're not only looking at CO2, which is the greenhouse gas that's most recognizable to folks, but clearly methane, and CFC's and ozone even more importantly; ozone being a greenhouse gas that's not emitted by pollution but is created by the chemistry of pollutants as they're transported to the Arctic. Trying to understand those things is an important part of this campaign.

Dr. Hal Maring

Program Scientist
Radiation Sciences Program for NASA
Fairbanks, AK

Full bio »

Q: What does NASA's Radiation Sciences Program study?

A: The science that my program is particularly responsible for is the transmission of solar radiation through the atmosphere, and that radiation reflected back out. So basically, the Earth's energy budget.

Q: What was the role of the NOAA P3 aircraft in this mission?

A: In particular, the measurements that are being made on the P3 that are part of what I'm interested in are looking at aerosols. So these are little particles that are carried through the air and they're formed either directly by combustion out of tailpipes of vehicles, or through chemical processes that take place in the atmosphere. A technical term would be secondary aerosols. They're formed from gas phase species that react and form these little particles and then what's of particular interest for us is the impact of those aerosols on radiation in the atmosphere. Do they reflect sunlight away from the Earth, do they absorb sunlight and cause warming in the atmosphere, do they cause warming in the atmosphere at a level above the Earth and actually then as a result cause cooling at the surface? Those are the kinds of processes and questions we're interested in.

Q: What are the goals of the spring and summer ARCTAS campaigns?

A: The two campaigns, the one now in the springtime here in Fairbanks was meant to be particularly focused on the transport of pollution produced by human beings from lower latitudes where a lot of people live, up here into the Arctic, and we have indeed found that. However, in the summer campaign we're going to be located at a place called Cold Lake in Canada, northern Canada, and we're going to be looking particularly at what gets produced by forest fires, and surprisingly we've been finding some forest fire up here in the Arctic and it appears as though fires that are currently burning in Asia, northern Asia, are, the emissions from those fires are being carried up here right now, something we didn't exactly expect.

Dr. Jack Dibb

University of New Hampshire
Platform Scientist for the DC-8
Co-Mission Scientist for the ARCTAS Project
Palmdale, CA
March 17, 2008

Full bio »

Q: What is your field of study and how does it relate to the ARCTAS mission?

A: I actually have been studying snow and air samples in Greenland to better understand ice core analyses that have been done by other folks in our group and in others around the world. And so we have a lot of the same issues that are motivating ARCTAS, like where does the air come from that gets to a place like Summit Greenland, how does it get out of the atmosphere, and onto the ground, and then recently we've discovered that there's very active processing of the snow when the sun shines on the snow, a lot of complicated chemistry happens that nobody knew about 10 years ago.

Q: What experiment are you conducting with the DC-8?

A: One of the things that we'll actually have is an experiment at Summit at the same time that the DC-8 is in Cold Lake this summer and there we're looking at evidence from the last three years that the hydroxyl (HOX) and what they call the HOX budget, the OH abundance of Summit is higher than expected and we think it's related to halogen oxide chemistry, reactive halogen chemistry, which is one of the target questions that the DC-8 will be addressing in the springtime over the Arctic Ocean north of Barrow and north of Greenland. So the halogens really perturb the fundamental chemistry of the troposphere and modify the ozone chemistry, and the NOX and HOX chemistry, and so we're going to try to find out with the DC-8, and that's the main reason we're going back to Summit this year, and obviously it, all of these things impact how you interpret an ice core but it's also increasing evidence that snow chemistry is influencing the composition of the lower atmosphere. And clearly that is seen in these ozone depletion, mercury depletion events that are pretty dramatic over the vast reaches of the Arctic basin that we'll target with the DC-8 during ARCTAS.

Q: Why is this study taking place in the Arctic?

A: The Arctic is unique because it has this, the public, the general public, in the lower 48 or where most people live, in the northern hemisphere, considers the Arctic as sort of a pristine wilderness. And we've known for about 30 or 40 years that that's not the case, that there is this phenomenon of Arctic haze. And so, that is an eye opener that even so far away from the big cities and industry that the pollution that we emit travels long distances and can build up. And certainly in the last five or ten years as we start to see more and more concern about climate change and the greenhouse gases causing warming of the atmosphere, one of the places that has been shown to be warming faster than anywhere else on Earth is the Arctic. And so certainly as the Arctic warms it's going to impact how the atmosphere is functioning, but there are a lot of reasons to think that changes in the atmosphere are contributing, or forcing, the Arctic warming.

Q: What recent changes in the Arctic have made the ARCTAS mission important?

A: One of the things that is of great interest in the last few years is why is the snow and ice melting earlier in the year and freezing up later and clearly, the air is a little warmer, but there's also speculation that the dirt and the black carbon that is in Arctic haze that's deposited just as the sun is coming up may actually change the albedo of the snow and hasten the melt season. And so where is this black carbon coming from? Is it increasing or decreasing over time? And does it have a measurable effect on the albedo of the white surface as we come out of the winter in the Arctic? These questions are a major motivation behind ARCTAS.