5 ms·

I still had trouble visualizing what you're describing. This is a typical cross-section[1]. To make it match what you're describing, I'd draw a slope from the

I still had trouble visualizing what you're describing. This is a typical cross-section[1]. To make it match what you're describing, I'd draw a slope from the grounding line and downward to the left, right? (Image depicts a flat bed underneath the ice, instead of a slope downward as you go inward) [1] http://cdn.antarcticglaciers.org/wp-content/uploads/2014/09/Fig-2.-Grounding-line.png http://cdn.antarcticglaciers.org/wp-content/uploads/2014/09/... EDIT: I think this image is a better representation: http://cdn.antarcticglaciers.org/wp-content/uploads/2014/05/PIG.ai_.jpg http://cdn.antarcticglaciers.org/wp-content/uploads/2014/05/...

dsfyu404ed 8y ago
Flip the terrain illustration in that picture left to right and make it steeper. The terrain that this particular glacier is a bowl that is well below sea level. The more the glacier retreats the deeper the water gets (because the terrain is deeper), the more of the glacier can be floated, the faster the glacier can melt. Imagine a pool that slopes from 3ft to 8ft full of ice melting. The thin part melts first, lifts up, water gets a little further underneath lifting the next bit of ice and melting it faster but because the pool gets deeper as you go the more ice can be lifted up and broken off so it melts faster as it goes. Edit: yes, your second image is spot on.
- deleted 8y ago
  [deleted]
- Gibbon1 8y ago
  First image alludes to something. Near freezing slightly warmer water is denser. So convection is reversed. Unless I'm mistaken.
  - function_seven 8y ago
    Both images show that convection pattern, but only the second image illustrates what parent was referring to, with the ground level dropping inward. As the groundline recedes, the surface area of ice exposed to the water increases, resulting in a positive feedback loop and further accelerating the melt rate.
  - lenticular 8y ago
    That's right. Water is most dense at about 4 degrees, and lower in sea water (around 1 C I believe). Below that, and water molecules start forming ephemeral crystal lattices. Since, weirdly, the hexagonal structure of ice lattices takes up more room than in liquid form, this makes the water less dense. Just to be clear, it isn't actually crystallizing at these temperatures, but due to fluctuations, crystal lattices can be briefly formed.

dsfyu404ed 8y ago

Flip the terrain illustration in that picture left to right and make it steeper. The terrain that this particular glacier is a bowl that is well below sea level. The more the glacier retreats the deeper the water gets (because the terrain is deeper), the more of the glacier can be floated, the faster the glacier can melt. Imagine a pool that slopes from 3ft to 8ft full of ice melting. The thin part melts first, lifts up, water gets a little further underneath lifting the next bit of ice and melting it faster but because the pool gets deeper as you go the more ice can be lifted up and broken off so it melts faster as it goes. Edit: yes, your second image is spot on.

deleted 8y ago
[deleted]
Gibbon1 8y ago
First image alludes to something. Near freezing slightly warmer water is denser. So convection is reversed. Unless I'm mistaken.
- function_seven 8y ago
  Both images show that convection pattern, but only the second image illustrates what parent was referring to, with the ground level dropping inward. As the groundline recedes, the surface area of ice exposed to the water increases, resulting in a positive feedback loop and further accelerating the melt rate.
- lenticular 8y ago
  That's right. Water is most dense at about 4 degrees, and lower in sea water (around 1 C I believe). Below that, and water molecules start forming ephemeral crystal lattices. Since, weirdly, the hexagonal structure of ice lattices takes up more room than in liquid form, this makes the water less dense. Just to be clear, it isn't actually crystallizing at these temperatures, but due to fluctuations, crystal lattices can be briefly formed.