It has been known that ChinaÃ(TM)s SO*/NO* was holding temps down all over northern hemisphere.
"Known" for values of "known" that go as far as "strongly suspect". But yeah, that's definitely a suspicion that climate scientists have had for years.
Oddly, I saw something the other day that might help the arctic.[pumping mechanism]
The Proposal has been around for a couple of years, but I didn't know it had been used previously.
the same thing we did back in the 60s to make rinks on lakes
I hope that someone did a deal of science on this back then, to constrain the uncertainties on the process. Obviously the presence of significant salt (~32 permil) would have an effect. The big problem I can see is how to keep the PV panels above the new ice that you're forming. You could - temporarily - solve that by putting the (floating) PV farm at some distance from the pump and new ice floe. Floating PV is certainly in development - but that then changes the problem to that of getting the floating PV to climb onto the edge of the expanding new ice floe ... which is a different problem. Maybe you'd need to put the PV farm up onto (buoy-supported) stilts, and allow the ice to form below the farm ... choices, choices.
This could be started in April using PV, and pulled out in oct.
Hmmm. Look at numbers. Say you need 10,000 of these, each producing a 1km radius reflective floe (so 31,416 sq.km extra ice - is that anything like the necessary scale? Another order of 10?) - that is a lot of deployments and retrievals. It very rapidly - long before you get to that scale (unless you want to be building many, many additional harbours, storage facilities, construction yards too. Boatyards ...) gets to the point of leaving the things at sea permanently. You've still got a servicing and deployment problem, but you haven't created a deployment/ retrieval problem.
Hopefully, this would not turn darker than normal since it will have a constant small particles falling on it
I don't think you'll be adding to the existing issue of "soot in ice" significantly, as long as you put your water inlets ... order of 10 times the diameter of the suction pipe above the seabed. That's an estimate - from the effects of pumping into fluids - and needs updating from (I hope) the 1960s experience you refer to. I'd start with a keel of 20x diameter, just to be on the safe side. That will affect the water depth you need for deployment, hence distance from shore, hence number of deployment harbours, construction/ assembly facilities ...
You're talking about the Alaskan and Canadian coasts, because the chances of getting Russia to contribute meaningfully is negligible, and there is zero infrastructure in Greenland on it's North coast (and a few hundred thousand sq.km of reflective land ice too, just next door). So .. the Canadian northern archipelago (where the complex bits of the NW passage are). Yeah, that's a complex question. How much overland transport do you rely on in winter (when it is less unreliable than intermittently-iced sea) ... complex.
Someone, somewhere should be doing test deployments. To see if it works at all. And if it works, how well?