Another hypothetical climate question

[nei]

Originally Posted by theunbrainwashed

I guess a better question to ask then, what if there was no Hudson Bay and Canada was just one big continuous landmass? Would the US have more Dw/Cw/Ds/Cs climates factoring in the presence of the Gulf as well?

My guess is the winters won't change that much. Once a body of water is frozen (sometime in mid to late fall) most of the moderating effect of the body of water is gone and the nearby landmasses won't be moderated more would any moisture come out of it. See my post on the effect of a frozen / unfrozen Arctic Ocean:

http://www.city-data.com/forum/26027707-post74.html

And regardless of any global warming, I'd assume that in any plausible scenario the Hudson Bay will remain frozen during the winter though perhaps a delayed melt could create interesting bay effect snow. During the warmer months, perhaps the Hudson Bay might have a cooling influence but the cold water might not add much to the humidity. The Hudson Bay doesn't seem to be much of a moisture source, Churchill is quite dry, more so in the winter. The Gulf of Mexico, in contrast, is the source of much of the eastern and central humidity and rain.

I'll retract my comment on a deeper Hudson Bay won't make a difference since the Arctic Ocean freezes. Since the Hudson Bay is further south and a bit isolated from the Arctic Ocean, a deeper Hudson Bay might still freeze but might be ice free for longer.

[Patricius Maximus]

Originally Posted by nei

And regardless of any global warming, I'd assume that in any plausible scenario the Hudson Bay will remain frozen during the winter though perhaps a delayed melt could create interesting bay effect snow. During the warmer months, perhaps the Hudson Bay might have a cooling influence but the cold water might not add much to the humidity. The Hudson Bay doesn't seem to be much of a moisture source, Churchill is quite dry, more so in the winter. The Gulf of Mexico, in contrast, is the source of much of the eastern and central humidity and rain.

It would take a lot of climatic warming to keep Hudson Bay from freezing over in the winter, so by the time you got to a scenario like that you'd be dealing with a completely different climate anyway (something more similar to present-day Kentucky than what's there now). So I think speculation on this front is sort of irrelevant.

During the winter Hudson Bay is frozen over so there isn't all that much of a moderating impact, but during the summer it could have something of a cooling effect, although the stats of the places downwind of Hudson Bay seem to feature summers about as warm as points upwind (lower 70's for highs). The only real moderating impact is close by Hudson Bay or the ocean.

[ColdCanadian]

Ice lingering on Hudso
n bay has ruined at least one June in Toronto in my lifetime. Last time it was responsible for the first two Weeks of June having daytime highs between 12-17
C (55-63 F).

A deeper Hudson would have a stronger impact on Toronto, possibly removing 1-3 C (2-5F) from our average July high

[Cambium]

Originally Posted by nei

And the Arctic Ocean obviously freezes over.

Thats what I was thinking. Depth has nothing to do with the surface freezing or down a couple feet. Wind has more to do with freezing over than depth because wind will keep it in motion and water is harder to freeze when moving. hence why rivers dont freeze over as fast. Also why its important to run water through your pipes in winter to prevent the pipes from freezing.

And I dont think the Hudson is large enough to affect climate. So the answer the the question should be... "nothing".

[nei]

Maybe not the US, but I'd guess it'd have a big effect on Canadian and maybe ocasionally the northern US. Could act like a local refrigerator since the ice sticks around to early June, a time when the subarctic often heats up. Here's a map of Canadian treeline:



http://fr.wikipedia.org/wiki/Fichier...e_line_map.png

I see some pattern from the lake, but if the lake was causing summer cooling I'd expect a lower treeline on the east side, and I don't.

[ColdCanadian]

Originally Posted by nei

I see some pattern from the lake, but if the lake was causing summer cooling I'd expect a lower treeline on the east side, and I don't.

take a close look at extreme northern Ontario.
A small portion in the middle of northern Ontario is beyond the tree line.
Much further south than the treeline west or east of the Hudson.

I've heard several meteorologists blame ice on Hudson Bay for very delayed start to summer in Toronto, despite being maybe 1000 miles south of it... so I'm not just making a guess.

[dunno what to put here]

Originally Posted by Cambium

Thats what I was thinking. Depth has nothing to do with the surface freezing or down a couple feet. Wind has more to do with freezing over than depth because wind will keep it in motion and water is harder to freeze when moving. hence why rivers dont freeze over as fast. Also why its important to run water through your pipes in winter to prevent the pipes from freezing.

And I dont think the Hudson is large enough to affect climate. So the answer the the question should be... "nothing".

But very deep water is less likely to freeze over significantly than shallow water.. and, of course it is large enough to affect the climate.. any body of water is large enough to affect climate, at least locally, even rivers.