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Operation IceBridge 2012 Antarctic Campaign video series - Operation IceBridge completed 16 science flights over Antarctica and nearby sea ice, flying once again out of Punta Arenas, Chile. https://earthclimate.eu/2016/10/19/how-scientists-study-antarctic-ice-melt/
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00:07Operation IceBridge
00:11IceBridge is off to a strong start this year, having completed seven science missions over
00:15outlet glaciers, sea ice, and ice sheets, and covering a broad range of territory both
00:21east and west of the Antarctic Peninsula. This is exactly the kind of start mission
00:25managers were hoping for when they prepared the aircraft thousands of miles away in California
00:30two weeks ago. Dryden has been invited by headquarters to play a pretty major role in Operation IceBridge
00:37when it comes to studying the Antarctic continent. So we've prepared the DC-8 with numerous instruments
00:43to fly long duration flights out of Punta Reina's Chile. For this year's campaign we've got a
00:49complement of about 17 scientists will be flying on board and we've got seven instruments
00:56installed and they range from lidars to radars to a gravity meter as well which is kind of a
01:02unique instrument. And the end of the campaign when we've flown roughly 15 sorties if we've
01:09hit the targets and they've successfully collected data then we know that we've done a good job.
01:15So this is the fourth year we are going back to Antarctica with the DC-8 and we have analyzed
01:21the data from the previous flights and the previous missions and we see that the ice sheets
01:28for example like Pine Island Glacier are rapidly thinning and the thinning is accelerating and
01:33it's spreading further and further inland so this is something we really have to keep an eye on and
01:39go back every year in order to make sure we collect the data that we need to feed into computer
01:45models
01:46that allow us to make predictions for the future.
01:50Until today the mission had yet to feature a return to the site of last year's discovery of a
01:56massive rift in the Pine Island Glacier. A huge flow of ice that has been called the weak underbelly
02:01of the West Antarctic ice sheet. Satellite images show the glacier is not calved yet but when it does
02:08this could produce an iceberg the size of New York City. Keep in mind that the main science objective
02:14of Operation IceBridge is to study how the ice is changing in polar regions on a much broader scale,
02:19not searching out calving events, but being at the right place at the right time provided a scientific bonus.
02:27IceBridge did a great job of surveying that crack and giving us a great visual on rift dynamics. I mean
02:35the ice
02:35melange that's in that rift is very interesting. IceBridge is based out of Chile to fly all sorts of flight
02:44lines
02:44associated with bridging the gap between ICESAT and ICESAT-2. They happened to survey it last year just fortuitously.
02:52It would be awesome if they could go back for sure. It wouldn't be directly their science but it would
02:59be great
02:59to see the evolution of that rift or possibly even a new survey associated with a new calving front.
03:07Today's mission featured a rare high-altitude flight over the Pine Island Glacier. As the aircraft returns,
03:13we wait for news of what the team found when they got there.
03:20We start with a visualization of AMSER-E data from the Aqua satellite showing sea ice, or frozen seawater,
03:27pulsing over the course of months around the Antarctic continent. IceBridge often passes the scenic Antarctic Peninsula
03:35on its way to survey the continent's ice sheets, glaciers, and surrounding sea ice.
03:40The peninsula's mountains are habitually shrouded by clouds, but today we have a clear view.
03:48As we descend, we see vast fields of sea ice. Large pieces of sea ice are called flows,
03:55and these formations often collide, creating thick ridges along their edges or raft over top of each other.
04:03This ice appears to be thick enough to be second-year ice, or ice which survived a summer melt season.
04:11Darker, grayer ice appears to be more recent, and might be around 10 cm thick,
04:16while the white ice covered by snow is probably more than 30 cm thick.
04:25The area in the lower center here is so smooth, it might be just a few hours old.
04:35This is frazil ice. It's granular like a slushy beverage, and is created by very dynamic conditions of turbulence in
04:42the water.
04:45This is a region of brash, containing sea ice and a few icebergs.
04:54IceBridge measures Antarctic ice from 500 meters above the surface, using radar, laser altimetry,
05:00and these crisp images from the DMS, or Digital Mapping System.
05:08Here, we have ice that's holding fast to the shore, and immobilizing icebergs created from a nearby glacier, or ice
05:15shelf.
05:16These slabs of ice, from continental ice shelves, sticking above the water by perhaps 50 meters,
05:22are large and flat enough to be called tabular bergs.
05:32Finally, the slowly setting sun lights up cracks, or leads in the sea ice, as we head for home.
05:43Operation IceBridge has now returned to the Pine Island Glacier, not once, but twice in 2012.
05:50And the year-old, giant crack in the glacier, poised to create an iceberg the size of New York City?
05:56Well, it's still there, and that iceberg has yet to break free.
06:00But the rift has grown longer, much wider, and spawned a secondary crack.
06:06Before we talk about when that mighty berg will be born, let's take a look at the IceBridge missions themselves.
06:12IceBridge's first return to the glacier was a high-altitude flight over the entire region, including the Thwaites, Smith, and
06:18Kohler glaciers.
06:20After this campaign is over, scientists will be able to compare this broad survey with previous year's measurements
06:26in order to better document the rapid and widespread changes in the region over time.
06:31For the second mission, NASA's DC-8 flew, as it does for most IceBridge flights, at 500 meters above the
06:37ice.
06:38And this mission was about creating a brand new set of data.
06:42The flight lines took the team over previously unmeasured tributaries of the glacier,
06:46and also surveyed the bedrock below them to provide a baseline for measuring change in the future.
06:52So why all this focus on the Pine Island region?
06:55NASA Goddard Calving Specialist Kelly Brunt says the ice in the region is substantially thinning,
07:00and its flow is accelerating.
07:03Ultimately, the change that we see in that whole region, not just Pine Island,
07:09but also its neighbor, Thwaites Glacier,
07:12this change represents the largest input to sea level rise from an Antarctic source.
07:20The rift has been an intriguing phenomenon to watch over this last year.
07:24But is it a really important event?
07:27When we talk about Antarctica, and we talk about the health and state of our ice sheets,
07:33we talk about mass balance.
07:35And what you have on one side of the mass balance equation is accumulation or snowfall coming in.
07:41And when we talk about balance, that has to be balanced by things coming out.
07:44And in Antarctica, that happens either through surface melt, or basal melt, or the big number in Antarctica,
07:51which is calving.
07:53Calving accounts for 80% of that side of the equation.
07:56So when you see calving in Antarctica, even calving where we use small states,
08:03or the island of Manhattan as a unit of measure, this is generally very normal.
08:07It's part of the process.
08:09However, Brunt says once the glacier calves, the new calving front will be further upstream
08:14from any calving front we've seen in the last 40 years.
08:17I've used the analogy of a fingernail to talk about calving.
08:23Generally, if your nail breaks in the white, it's normal, and you don't worry about it.
08:29If your nail breaks below the white, you think about it, you remember it.
08:33If you lose your whole nail, that's a big deal.
08:36Much of the calving, the 80% of the net loss through calving,
08:42can be equated to losing the white part of your fingernail.
08:45Things that we saw in the early 2000s in the Antarctic Peninsula side,
08:49the Larson A, the Larson B, that's equivalent to losing your whole nail.
08:54What's going on in Pine Island is probably that intermediate,
08:59that we've broken our nail and it's below the white,
09:02and it's something to watch and something to monitor over time.
09:07As a byproduct of the recent IceBridge flights,
09:10the team got some great views and measurements of the evolving crack,
09:14which has been filled in somewhat by blowing snow.
09:18The crack appears to have only a short distance to go before a new iceberg is born.
09:23It's still hard to know when that will happen, but conditions seem to be right.
09:27Sea ice acts as a buttress or a dampener for sea swell that actually protects the front of these ice
09:35shelves
09:36or the front of these floating glaciers from calving.
09:38So the fact that there's no sea ice in front of the Pine Island Glacier right now
09:43implies that it might be in a state that's sort of primed to calve.
09:47After IceBridge heads back home from this campaign,
09:50its data will be used to monitor the state of Antarctic ice sheets,
09:54while satellites will continue to watch the rift in the Pine Island Glacier as the melt season continues.
10:07Okay John, could you give us a sense of how this mission was designed,
10:11your weather thoughts coming into it,
10:13and the scenery coming in over the calving front, that sort of thing?
10:18Okay, sounds good.
10:20My name is John Sontag, I'm a senior scientist with the ATM team.
10:25That's Airborne Topographic Mapper.
10:28Today's mission was called the Recovery Offshore 1 mission,
10:31made up of six parallel lines spaced at 20 kilometers.
10:35It's called that because we concentrate on the area where the Recovery Glacier,
10:39which is a major glacier in this part of East Antarctica,
10:41drains into the Filchner ice shelf.
10:43It tends to be difficult to get measurements to help us understand the shape of the cavity of water,
10:49ocean water, beneath an ice shelf, such as the Filchner, especially a big one like the Filchner.
10:54And with our gravity instruments and our radar instruments on board the DC-8,
10:59we are able to collect measurements which allow analysts and scientists to deduce the shape of those underwater cavities.
11:05And that's important because by knowing the shape of those cavities,
11:10scientists can begin to get at the interaction of these glaciers with warm ocean waters,
11:16which has been determined within the last decade or two by the glaciological community,
11:21that the interaction of these large glaciers and warming ocean waters tend to be quite important in determining their future
11:28behavior.
11:29The weather today was probably not what you would call ideal.
11:33We knew that there would be a cloud layer between 8,000 and 10,000 feet,
11:37and we had a lot of confidence in this particular forecast.
11:40So our transit in this morning took us over the southern part of the Antarctic Peninsula
11:45and over the extreme southern part of the Wooddale just in front of the Ronnie Ice Shelf.
11:50And sure enough, most of it was clouded as the models predicted it would be.
11:54We could see bits of sea ice surface here and there.
11:58But when we made our descent into the Filchner Ice Shelf area,
12:01we could see the edge of the ice shelf and the edge of Berkner Island.
12:04It was clear skies there.
12:06And when we got on site, we were very pleased to see that the forecast indeed held up
12:14with the low sun angle that you get down in these parts.
12:17And just a beautiful, beautiful, beautiful scene.
12:20So it went very well today.