Decrease in Atlantic circulation?

[x-y-no]

Do you have any figures to how the much the salinity has dropped?

The Curry & Mauritzen paper I cited above seems only to be available by subscription online.

There is some good discussion at: http://www.realclimate.org/index.php?p=191#more-191


BTW, in googling around a bit today on this topic, I keep running across references to "The Rooth Model" of the THC in quite up-to-date work. Always entertaining to see my dad's work still playing a part in ongoing research.

[Jim Hughes]

There is some good discussion at: http://www.realclimate.org/index.php?p=191#more-191

This research paper mentions what I was talking about in my last post. "The Great salanity anomaly". It happened earlier then I remembered.

[P.K.]

Do you have any figures to how the much the salinity has dropped?

The Curry & Mauritzen paper I cited above seems only to be available by subscription online.

lol, I took that out of my post as I found something about it (And had also managed to miss the post when you refered to that.) One of the papers I refered to is here, but it is possible you won't be able to access it in the way I can. (Note: I haven't had time to read the article fully yet)

[P.K.]

Right looking into this further. The stats from the 1998 cruise showed this slow down but maybe they didn't want to publish anything until they did a further test.

This slow down would give a temperature decrease of around 1C here since 1998 yet we haven't seen this. As expected given the Gulf Stream hasn't changed in strength the recirculation has increased, maybe part of the reason why TC activity has been so active over the last few years given the extra transport of energy around the subtropical gyre rather than to the NAD. (As well as the AMO, or possibly involved with it)

However the errors on these latest measurements are large and it is not know if there is a seasonal cycle of the THC and how much it could change throughout the year.

Some people here (And at Southampton) are looking into measuring these flows using moorings rather than by ship measurements. See http://rapid.nerc.ac.uk

[x-y-no]

Right looking into this further. The stats from the 1998 cruise showed this slow down but maybe they didn't want to publish anything until they did a further test.

This slow down would give a temperature decrease of around 1C here since 1998 yet we haven't seen this. As expected given the Gulf Stream hasn't changed in strength the recirculation has increased, maybe part of the reason why TC activity has been so active over the last few years given the extra transport of energy around the subtropical gyre rather than to the NAD. (As well as the AMO, or possibly involved with it)

Makes sense to me.

However the errors on these latest measurements are large and it is not know if there is a seasonal cycle of the THC and how much it could change throughout the year.

Yeah, that +/- 6Sv error bar is pretty huge, isn't it?

Some people here (And at Southampton) are looking into measuring these flows using moorings rather than by ship measurements. See http://rapid.nerc.ac.uk

Even one more cruise doing the same measurements in the next year or two would be hugely helpful, I think. Right now we don't have enough to say this is a trend (and at least some reason in the north Atlantic SSTs to think it might not be).

[P.K.]

Problem is at around £10,000 per day for the just the ship for one of these things you need to find someone to put up the money. The RAPID project has moorings set up across the Atlantic to continuously monitor this.

You should be able to access the free data at http://www.bodc.ac.uk/rapidmoc/

It is of course possible that we have had a temperature decrease here due to that but it is hidden by AGW (Or various other things such as the NAO) so this needs to be looked at carefully.

6Sv is a huge error given all the questions I've ever had to do on this.

[x-y-no]

I would refer anyone interested in this dicussion to comment #25 by Martin Visbeck at:

http://www.realclimate.org/index.php?p=225#more-225

He raises some potential problems with the methodology of this work which look like legitimate issues to me.

I'm not willing to jump on this as a result to get excited about yet.