Albert, I thought about using cables to keep ice in place before, but I don't think the calculations stack up. Ice is nowhere near as strong in shear and tension as steel. However the surface area of the join between large pieces of ice is huge, compared to the tiny cross-sectional area of a cable. Therefore, any force which can break up the ice is likely to make pretty light work of any cabling you string up in it's place.
This doesn't account for fractures which propagate through floating ice, (such as might be caused by a passing tsunami). In such cases, the flexibility of a cable array would be a positive advantage. However, I don't think that such events are common, and I imaging that shear from hydrodynamic drag in moving water, and tidal flexing, is probably what cracks most ice. This is really speculation on my part. I'm a recovering engineer, not an ice-dynamicist, or whatever they might be called. Hopefully there's someone on this list who has a expertise in both materials science and ice dynamics, so they can comment on whether stringing together bits of ice is a good idea or not. A 2009/10/1 Veli Albert Kallio <[email protected]>: > Dear All, > > The Robeson Channel Suitable for Suspension Cabling to Prevent ice Escape? > > Please find enclosed a brief satellite animation on the Robeson Channel from > this summer which suggest that use of bridge-style suspension cabling could > hold ice in place and prevent it moving into the warm waters further along > the channel between Ellesmere Island and Greenland. The link attached below > which shows the summertime ice movements. > > http://www.greenpeace.org/finland/fi/mediakeskus/lehdistotiedotteet/greenpeace-dokumentoi-pohjoise > > The shortest suspension cables would be Ellesmere - Hans Island - Greenland > two stretches 8 and 12 kilometres wide. (The concept is to create ice > congestion behind barrier that forms a self-locking jam of pack ice behind > cable so that ice survives longer in the cold waters that if allowed to > float to the south.) > > On the negative side, the ice amount south of any successful cable barrier > will decrease. > > The impact of cables for boats, whales and other wild life would have to > be addressed. After melting, the barrier cable is lowered to the seafloor, > or, when the sea ice is on northward reverse movement. The cable barrier is > raised up to surface whenever there is ice flow moving southward. It is also > raised up to surface in autumn for the winter freeze. > > In Nunavut, the suspension cabling could help to keep the North West Passage > clear of thick sea ice floes that damage ships while preserving ice on the > north side of the channel. > > The benefit for the shipping may help to justify a cable system in Nunavut > arhcipelago. > > Cables could enlarge the profiles of the Swalbard Islands and Franz Joseph > Land by blocking the straights between islands by cables. This would > increase the ice congestion behind these archipelagoes and decrease the sea > ice escape from the high Arctic Basin. > > I have not considered blocking of the Fram Staight due to its width, but > materially the largest amount of sea ice loss through escape occurs there. > The barriers to sea ice movement can slow down ice movement and reduce ice > loss to the south due to decreases in ice movements - but if ice melts away > due to warm weather behind the barrier, the cable measures become all but > useless for the part of year when there is sheer lack of ice. > > Kind regards, > > Albert > > From: [email protected] > To: [email protected] > Subject: Greenpeace dokumentoi pohjoisen pallonpuoliskon jäätiköiden > sulamista > Date: Thu, 1 Oct 2009 14:18:14 +0300 > > http://www.greenpeace.org/finland/fi/mediakeskus/lehdistotiedotteet/greenpeace-dokumentoi-pohjoise > > ________________________________ > Beyond Hotmail - see what else you can do with Windows Live. Find out more. > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
