Claire Parkinson, Elizabeth Arnold
Sea ice discussion.
NPR/NGS Radio Expeditions
25 Apr 1999
- 74.6841088 -94.9040222
DPA4006 omni mics; Sonosax preamp
Show: North Pole
Log of DAT #: 3
"Resolute #2 (Spaced Omnis)"
ng = not good
ok = okay
g = good
vg = very good
sound begins with conversation and preparation to leave
walking downstairs and onto snow
Who are you?
I'm Claire Parkinson from NASA's Goddard Space Flight Center
And how long have you worked there?
For 20 years. Well, almost 21 years.
And what do you do there?
I'm a scientist. Most of my research has been on sea ice in the Arctic and the Antarctic and most of it has been with satellite images and analyzing satellite data. I'm also the project scientist for a mission that's going up, in terms of being launched, in December of the year 2000. And that mission, that's a satellite mission, so it's got a spacecraft and then it's got six instruments on the spacecraft, and they'll be measuring all sorts of things. Atmospheric temperatures, and humidities, and vegetation on the land, sea ice, snow cover, just a whole stack of, sea surface temperature, all sorts of things regarding Earth's climate, but that doesn't get launched for another year and a half.
How do you learn about what's happening in terms of sea ice from pictures that are taken from satellites?
Okay, there are¿depending on which type of radiation you're using, you can learn a lot of different things. If you're using something like visible radiation, which is the kind of radiation that our eyes see, then you'll see the same type of thing that you would see if you were up in a plane going over the ice cover. So, in other words, you would see what actually looks like an ice float. The problem with that, is just the same as when you're up in a plane and you're looking down, if there's a cloud in the way, you see a cloud instead of the sea ice. Same thing if a satellite's taking data in the visible wavelengths then when there's a cloud in the way, you can't see the data you're looking for at the surface. Course, if you're studying clouds instead, then it's great. But if you're studying something at the surface, whether it's sea ice, or sea surface temperature, or vegetation or whatever, then the visible radiation has that limitation of the clouds get in the way and the other main limitation would be that if it's dark out, you can't get your data, just like your eyes can't see if it's dark out, that the satellite's looking in the same wavelengths that our eyes see, visible wavelengths, that you can't get your data if it's dark out. And so, for that reason, especially in the polar region, when it's dark for months at a time, for that reason, most of the research that I've done and a lot of others who have used satellite data for sea ice have done, does not use visible radiation. Instead it uses microwave radiation, 'cause microwaves, it turns out, microwaves pretty much go straight through the clouds, and when you're using microwave radiation for an Earth-observing satellite, it's radiation that is actually emitted by the Earth and the Earth's surface, so it doesn't require sunlight. So, if it's dark out it doesn't matter, because we're really measuring the radiation that sea ice is emitting and that the ocean is emitting and we're able to tell where the sea ice is because it turns out in microwave wavelengths, in lot of the microwave wavelengths, sea ice ends up emitting a lot more than ocean, than open, you know, liquid water does. So, the ice emits more than the water, and as a result, when we get our satellite data back on the microwave radiation, we can see, "Oh, that area is emitting a whole lot. That must be sea ice. And another area is emitting just a little, it must be liquid water and not sea ice." And so, we're able to get these images, we're able to get pretty much global data on about an everyday or every couple of days basis. And this has just been phenomenal, in terms of, polar regions are notoriously difficult to do studies in because of the weather conditions and to have a satellite up there that can actually give you images everyday as to what the sea ice conditions is like is just great. One of the limitations of the microwave data is you don't see the individual ice flows. Instead you get one data number, you get one number for an area that's about 20 to 50 kilometers diameter. I mean, that's a huge area and you just get one number, but that one number allows you to calculate what fraction of that area is covered by sea ice. And so, we get these very good indications from the satellites of where sea ice is any particular day or any few days. What we don't get would be things like how thick is the ice. Someday, we might be able to get that, because someday, I assume, some clever engineer is going to come up with a technique of how to get ice thickness from satellites, but so far we don't have a good technique to get the thickness, but we are able to get the distribution of the ice, and roughly what's the concentration, meaning percent aerial coverage, in each of these fairly large pixels in both the Arctic and the Antarctic regions.
What are you hoping to learn by being here?
I'd like to check the thickness of the ice in North Polar, right near the North Pole. There was an expedition that was in the Arctic last year. It was another part of the Arctic. It was called the "Sheba" expedition, which stands for Surface Heat Budget of the Arctic, and it was in the Beaufort Sea region, which is right north of Alaska, and they found that the ice was a whole lot thinner than they had anticipated. And¿of course, nobody knows yet whether or not that's, should be a major concern. It would be a major concern if indeed, that's true all over the Arctic, but any ship is only going to be located where ever it is, and it might travel around a bit, but it's a limited area that the SHBA expedition was, but the fact that they found ice to be a quite a bit thinner than what they expected on the basis of a project that took place in the 1970s, which was the "Aidex" project, which stands for Arctic Ice Dynamics Experiment. That project, they found much thicker ice in the same general location as the SHBA expedition last year. If the ice is thinning broadly across the Arctic, this could be an indicator of climate change and if the ice, some people have said, after seeing the SHBA results they've said, the ice might disappear altogether within the next hundred years. If that were to happen, there are all sorts of consequences, both to the climate and to animal life forms. And so, we're only going to get a few more data points on the ice thickness, so we're certainly not going to solve this problem, but we're gonna get a few more points, which is better that what we have now.
Some indication of what's happening.
Yes. Certainly if we end up with very thick ice, it would be a relief. It would suggest that maybe the SHBA results were just localized, but since we'll only be at a very localized area, too, nothing conclusive could come about in terms of the picture of the Arctic as a whole just from this expedition, but we're hoping to just add a little bit.
How will you do that? Will you do that with augers or with¿
Yes, we've got a hand-powered drill and that, we tested out that on Thursday night, and also Friday and it worked very well. It's got pieces that are about a meter long and you drill it by hand until you've gotten down to the ground level, so you've about a meter of thickness of ice has been drilled. Then you pull it up, you stick on the next meter, so that it becomes two meters deep. You put it down in, you drill it, and in our case, since we were just out here in Resolute Bay, where the ice is not real thick. In our case, by the time we got the two meter one down, it was so obvious as soon as you got through the ice. I mean, all of a sudden there was just dramatic change, and you know you're at the end of the ice. And then, it ended up that the measurement was between one and (bell begins ringing) two meters and ended up five feet, one half inch in terms of feet and inches. So it's five feet deep in Resolute Bay, and then after you pull this drill out¿
g- church bells ring as dogs howl
So it's like a drill bit and you keep adding to it and then you feel when it goes through¿
And then after you pull it out, it's this really cool little device. There's a measuring, a regular measuring tape, but at the end of it, there's this little device so that, if all you had was the measuring tape, if you drop it down too hard and you know when the measuring tape hits the bottom of the ice, you don't know, but there's this cool little device so that it both produces a weight so that the measuring tape goes down straight, but you open it up before you put it down, and then so that it opens up horizontally with the hinge in the middle, so it opens up horizontally with the hinge in the middle and then you twist it around vertically as you drop it down. So it drops down vertically, but when it gets underneath the ice, it rotates back so it's horizontal, so as you pull a little on it, all of a sudden you realize, "Oops, it's down there. It's locked against the ice." But because of the way the mechanism works, you of course don't want it to be locked against the ice and you can never get it back because then you couldn't measure your next hole. But so, you lock it against the ice, you read the tape measure to see how thick the ice is, and then you just yank a little, and it closes up on that same hinge, and then you pull it up. So it's kind of a cool little device to actually get the ice thickness.
What about the ozone stuff that you're doing? That is in relation to measuring the thickness of the ice as well, isn't it?
Actually, they're two separate studies, but the ozone, just like the ice thickness, the concern that there might be some climate change going on. In the ice thickness, there is also concern that there might be changes going on in the ozone. There is also concern that there might be changes going on in the ozone layer, especially since the so-called "ozone hole" in the Antarctic has certainly, it seems that there have been prominent decreases in the ozone in the stratosphere of both the Antarctic, especially in the Antarctic springtime, which would be October. And right now, in April, it's the Arctic springtime and it seems that there've been some decreases in the Arctic ozone. However, when one hears about the ozone hole, usually you think of much, much less ozone than normal, and that's why it's called a hole, even though it doesn't mean there's no ozone, because there definitely is some ozone. But in the Arctic case, if you look, I took one of the satellite images just before we left a week ago from Goddard and I looked at the satellite image of the ozone. In fact, you can, anybody can pick up these images, they're on the web. So everybody could pick them up, kind of, within the last day or two. So that's the way I got it, I just went into the web and got the picture off, a global picture of what was¿and it turns out that in the Resolute Bay area, it's about the highest of ozone any place in the Northern Hemisphere. So it's, and yet still, people are talking about the ozone depletion in the Arctic. So it's not as though it's less, than say, over Washington, DC, because certainly that image, it was not less, it was quite a bit more than what was over Washington, DC. But it's less from one year to another, and so the concern is that it's being depleted.
And so that's what that tells us, that's what you're looking to find.
And so what we're doing is we're taking it, we've got a handheld measuring device to measure the ozone and we're going to be comparing that with the satellite data to see if the handheld results come out the same as the, sort of as a test of the validity of both the satellite data and the handheld device
Is that ground truthing?
That's ground truthing, yes. And so that's what we're doing in terms of the ozone. And in terms of both the satellite measurements and this handheld little device, both of them are measuring in the ultraviolet radiation, which is radiation that is slightly, so called, more energetic, which ends up being shorter wavelength radiation than visible radiation. So it's the other side from where the microwave is, which is longer wavelength radiation. In the ultraviolet, and that's very much connected with ozone because when people speak about concerns with the ozone hole or depletion of the ozone layer, the concern is basically because the ozone up there in the ozone layer is protecting all life forms at the surface from the intensity of the ultraviolet radiation from the sun if that ozone weren't up there and absorbing some of it. And so, we would get more sunburns, more skin cancer, more cataracts in the eyes, some people say even immune deficiencies would be affected, and it's not just humans, it's lots of animal life forms that would be affected, and probably plants also as ozone gets depleted in the upper atmosphere.
So you're trying to figure out whether that buffer is being chipped away at or is remaining constant? Have you ever been to the North Pole? What do you think about that?
I think it's cool to get the opportunity to go. I hope we make it. I realize that there's always the issue of weather condition might not allow the plane to land, but I think it's a cool thing to get to do.
What are you hoping to find?
I'm hoping to find that the ozone layer is about what it was a year ago. I'm hoping to find the thicknesses thicker than what they were finding in the Beaufort Sea last year with the SHBA expedition. And basically, I've studied sea ice for like 20 years now at Goddard and the last summer I was actually out on the sea ice was way back in the early 1980s, so it's just always good for a scientist to just get out and look at what they're studying every once in a while. And so I think for me that's a good opportunity to do that.
Was that in the Antarctic?
I've been to the Antarctic when I was, in the case of the sea ice, it was actually, in the early 1980s, it was actually in the Bering Sea in between Siberia and Alaska. In the Antarctic case, I was studying land ice at that time rather than sea ice, but I have been to both the Antarctic and the Bering Sea and the Arctic.
How would you just explain it to some guy sitting in his armchair in Ohio? Why does it matter to him what might be happening to the sea ice up here?
Okay, it probably, it's probably not something he really has to be concerned about, but if he's the type of person who looks at the global picture on things, sea ice ends up having a big impact on both the atmosphere and the ocean, in terms of, sea ice essentially insulates the ocean and the atmosphere from each other so that heat fluxes. As the sea ice flows apart and open water is exposed in between, if it's a cold winter day like we're experiencing right now, then the heat that's in the ocean and the water that's in the ocean can't be much below freezing or else it would be frozen. And so there's water there that's roughly at the freezing point, which is way, way warmer than the air temperature, and so lots of heat goes up through these exposed areas, so as flows in the ice move apart. The presence of the ice, therefore, is keeping that heat more locked into the ocean than it otherwise would be, and once it gets into the atmosphere a lot of it will just end up going out, away from the climate system. And then, the other thing, if you look at sea ice, it looks white. The reason it looks white is because solar radiation that comes down and hits it gets reflected off it and gets to your eyes and it looks white. If something looks really dark, like the ocean's surface, it means that the sun's rays that come into it are predominantly getting absorbed in it. And that's the same reason why people suggest wearing black clothing in winter and white clothing in summer, so that the sun's rays will reflect off you in summer and they'll get absorbed and help warm you in winter. So, in the case of the sea ice versus the open water there, if the ice were to all go away, instead of having the sun's radiation primarily reflected off by this ice cover, it would be predominantly absorbed into the ocean, and the whole system would end up warming up. And so that's why a lot of people say that sea ice adds like a positive feedback to climate change, so that climate warming occurs, sea ice will begin to melt. Because it's melted, you get more heat absorbed in the system because these mechanisms, and then it means climate warms a little more, and then a little more sea ice melts, and then climate warms a little more. So it's a called a positive feedback, this sequence that kind of feeds on itself. And so in terms of climate, that's one reason why it's important. Now most people think of ice as kind of a pure thing and they have no idea that lots of little organisms live in the ice. Algae live in the ice and lots of little organisms live in the ice and then bigger organisms underneath the ice feed on those organisms, and then fish feed on them, and seals feed on the fish and polar bears feed on the seals, so all the way up through the food chain, you've got an impact of the ice. And polar bears, for one example, polar bears, they wander around on the ice a lot, and in fact that's where, traditionally, their predominant amount of their feeding takes place from the ice, and they feed by feeding off the ice, like catching a seal right off the ice, or a seal that's actually come up onto the ice. In a place like the Hudson Bay region, where sea ice disappears for the summertime because it's all melted away. In a place like that, the polar bears are forced onto the land during the summertime and it turns out that until humans were around and polar bears have fed on human, you know, in garbage cans, and other human
Polar bears traditionally would, in the wintertime they'd be on the ice and they'd be eating in their normal diet. Then in summertime they'd be off the ice, onto the land, and essentially no real source of food, or the food that there wasn't, they generally wouldn't eat it. So they'd essentially they'd be fasting during the summertime. As the sea ice period in Hudson Bay, if it is to get a shorter sea ice season, then, and in fact, people have seen that sea ice seasons that are shorter, the polar bears by the end of that summer season when they are fasting. So the sea ice season is shorter than the summer season where there is no sea ice is longer, so they're fasting for a longer period and by the end of that period, they become more emaciated. And so, their concern has been raised that if the sea ice disappears, what will happen to the polar bears? Will the polar bears disappear also? Just in terms of, their lifestyle is so dependent on the ice.
So basically you're telling me that sea ice, there's a global, it allows us a global perspective in terms of what's happening with climate. But also, it's a link in the food chain. How do you feel about going to the North Pole?
Oh, I like it. I mean, I like getting the chance to do it. We camped out last night to make sure that we would be able to, as a test of both ourselves and also of the tent and the sleeping bags and we all made it last night and we were very pleased. Four of our group had camped out a few nights ago and two did very well and the other two who were in a different tent from the two who did very well had a very rough time and that little test a few nights ago was very useful because the result of it was we went and got a much better tent. So last night with the much better tent, everybody did very well, including the two who had had a problem several nights ago.
So science aside, you have some pretty practical concerns too.
Yes, keeping warm is tough. Like my hands were freezing quite a bit yesterday, but I've got much better mittens on right now and my hands are doing just fine.
That's it for now.
distant dog barking, some background voices
door closes, dog continues, wind blow
g snow blowing with wind moaning, dog continues barking
feet walking in snow (loud), dog barks in background
dog louder, walking quieter
dog bark (distant) with wind and snow blowing
walking in snow
very distant dog barking while wind howls
snow mobile with dog barking in distance
dog bark, wind howl
g- wind gust, blowing drifting snow with distant dog barks
wind howl/blowing snow
walking back to NASA's Resolute house with dog barking
two dogs barking (one more distant)- g dog sounds
Entering Resolute house