14 November 2016 So Many Kinds of Ice!!

Ice Shelves vs. Ice Sheets vs. Ice Tongue vs. Marine Ice

Ice shelves are found in polar regions, at the edges of ice sheets. They occur as land based ice sheets meet the ocean waters and float out away from the land. It might be hard to imagine such massive objects floating, but like any ice, their density is slightly less than water. Fresh water is also slightly less dense than salt water, as there is less "stuff" (in this case salt) to increase the density of sea water. Ice FloatsSea ice is frozen sea water while ice from ice shelves or tongues is "new" to the ocean system. Since ice shelves have already affected the sea level upon entering the ocean (think: ice cubes already in a glass will not raise water level when they melt), their melt will not really increase sea level. However, there is a small sea level increase because the volume of the sea water needed to displace a floating fresh water ice shelf is slightly less than the volume of the fresh water contained in the floating ice. But overall, this does not cause a large change in sea level. Glacial IceIce on the land is thick, so as it reaches the ocean on a shelf, it has ability to add a lot of new water. What DOES change and potentially greatly impact sea level is increased melt of glaciers upstream which can happen if the ice shelf melts quickly and allows the land glacier to advance and therefor melt. When an ice shelf holds back the uphill glacier feeding it, it is called "buttressing". This can happen because the ice shelf is pinned to rock along the side and/or bottom, and offers some stability to the system. An “ice tongue” can develop as a freely floating section of ice shelf that flows outward quite quickly and has no buttressing at all - imagine someone sticking their tongue out. Additionally, the ice shelf can freeze to sea water, leading to a mixture of types of ice called “marine ice”. Operation IceBridge looks closely at ice shelves to determine the contact and buttressing characteristics below the ice as well as the nature of each type of ice. Sea Ice with ReflectionSmall areas of open water between ice reflect bright sunshine near the edge of the Southern Peninsula.

Life Onboard

The incredible 6th graders at my school, Rocky Mountain School of Expeditionary Learning and their inspired teacher Lauren Cain made beautiful flags for me to bring along. Here, scientist Margi Turrin, ATM Co-PI John Sonntag, and mission engineer Matt Berry hold them up for a photo. These flags flew all over Antarctica! Thank you 6th grade for coming along with me to Antarctica! 6th Grade FlagsMade by RMSEL 6th graders, these flags flew over Antarctica! I was invited up to the cockpit for a wild ride over the Fleming Glacier today. It was the most incredible flight I have ever had, or probably will ever have. When Stu, our pilot, said "this is the most beautiful thing I've ever seen" you know it's special. Our pilots Stu Broce, Frank Batteas and Matt Pitch flew us at 15,000' over pointed mountain peaks jutting through bright blue glaciers - wow! When safety tech Lyn said "You're spoiled now" he wasn't kidding! S. Peninsula topographyThe mountains along the southern peninsula are stunning! Plane on crevassesAs we fly, we sometimes see our reflection. This helps us grapple with the sense of scale of the landscape. S. Peninsula  terrainThe landscape is stunning, and from the cockpit, I can see 180+ degrees. Amazing! Hanging out in the cockpit taught me a lot about why these skilled and adventurous pilots choose to work for NASA. Pilot FrankFrank Batteas flies us through some rugged terrain, low and close to the mountains. Pilot StuPilot Stu had a fantastic time flying through the crazy terrain. cockpit So much going on in the cockpit.

Comments

Sofie Maliyevsky
Guest's picture
Ice

What is your favorite part of the missions when you are working with ice?

Guest
Guest's picture
ice

Hi Sofie!
The favorite part of the mission, honestly, is learning about the ice. There are so many things going on and the ice tells such a great story, but I didn't know enough before this trip to understand it all. I understand a lot more now, and would love to keep learning about it. I also love looking at the landscape, and talking to interesting people, but the learning is the best part for me.

trevor lantz
Guest's picture
ice

which one of the ice are tougher.

Guest
Guest's picture
tougher ice

Hi Trevor!
cool question! The land ice is for sure the toughest as it is so thick. At the South Pole, it is over 4 km thick! Wow! The sea ice is much thinner and easier to crack or deform.

calvin allshouse
Guest's picture
what was the most "colorful"

what was the most "colorful" part of the trip

Guest
Guest's picture
Colorful

Hi Calvin!
The most colorful part of the trip - hmmm. I can answer that a few different ways. First of all, the town of Punta Arenas where we were based, is very colorful. On my last journal entry I have a photo from up on the hill above town and you can see how colorful the roofs are. The town also had street vendors and colorful murals on some of the buildings. Secondly, the people I got to work with were "colorful" in that they were funny and many were very talkative. Often on the comute home from Antarctica back to Chile, great conversations came up through the headsets that made everyone laugh.

Bryce Harper
Guest's picture
melting glaicers

Is the water at a warm enough tempurture to melt a glacier over a long period of time?

Guest
Guest's picture
Melting Glaciers

Hi Bryce, super-amazing question!
YES, the water is cold but it is warmer than the ice, so it has the ability to melt the ice. This is one of the most fundamental and interesting pieces to the work of OIB, as the ice shelves that extend out from the continent are floating on warming water. This effects their melt from below, speeding it up. As the shelf thins, it may also become more buoyant and loose its anchor contact to rocks below or at the sides, allowing it to move forward more readily. Yes, ocean water melting ice is a really important part of the story.

kayleigh
Guest's picture
witch one of the three kinds

witch one of the three kinds of ice melt the fastest?

Which one of the three kinds

Hi Kayleigh! Great question! The sea ice is very thin so it can melt quite easily as the water warms, BUT the underside of ice shelves can also melt a lot with the warmer water below, so they are vulnerable to a lot of melt. Because sea ice is made from ocean water, it is not ADDING to the water level when it melts, but land based ice, like ice shelves, do add to the ocean water level when they melt. This is an important area of study because of what it might mean to sea level rise, so while the sea ice may melt faster, the ice shelves' melt may mean a lot more to the planet. Thanks for your awesome question!

Macon
Guest's picture
ice types

What kind of ice is most common in the south pole?

Ice Types

Hi Macon! Great question! At South Pole, the very thick ice (4-5 km thick- yikes!) is over the center of the continent so it is an ICE SHEET there. It is thick and old and very cold. Thanks for your question!

Macon
Guest's picture
ice types

What kind of ice is most common in the south pole?

Operation IceBridge Antarctica

Subscribe

Subscribe to the Operation IceBridge Antarctica journals using the form below.

Email:

Team Member

Maggie Kane's picture

Journal Details

Location: George VI Ice Shelf
Coordinates:
Latitude: 67° 28' 48" S
Longitude: 71° 6' 0" W
Weather Summary: Clear and Cold

Operation IceBridge Antarctica Journals

Ask the Team