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Thread: AMOC aka the Gulf Stream System, is it a weakening trend?

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    AMOC aka the Gulf Stream System, is it a weakening trend?

    I have been looking at some evidence such as this
    http://www.realclimate.org/index.php...g-circulation/

    It is a link discussing the reduction in the gulf stream during the last decade. We are reminded this is a highly non linear system and if it declines too much, it will drastically change the climate in the North Atlantic towards the cold end of extreme. It does seem it is weaker now than in recorded history (not necessarily a really long record) but separate records of sea surface temperature may be a good proxy for the current.

    Is it related in any way to the anomaly in Oklahoma where the usual series of tornados in April has not happened?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
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    I don't know the answer to your question but I don't think AMOC is synonymous with Gulf Stream. The latter is part of the former. Your linked article uses the term Gulf Stream System.

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    Quote Originally Posted by profloater View Post
    Is it related in any way to the anomaly in Oklahoma where the usual series of tornados in April has not happened?
    I don't know, but I think that would be a stretch.

    My understanding is that the tornado activity in the US midwest is powered by two things: warm, moist air coming out of the Gulf of Mexico and the cool air coming from the west over the Rockie Mountains (and the changes in pressure that air encounters). I don't see how the Gulf Stream would directly relate to the Gulf of Mexico.

    I don't know that anyone knows why the tornado season has been quiet so far, but it may also be rapidly change (storm threats in the Midwest today). It may be related to climate change (I think changes in the Gulf Stream almost certainly are), but I don't know that anyone knows.
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    I suppose the ocean currents all link up With their combination of warm surfaces and cold deep salty currents and the article shows the distribution of the heat in the oceans is not obvious so some regions are warming and others cooling. We are seeing Beluga whales near the uk presumably because of local cooling. It's a big picture to comprehend, colder water holds more oxygen. I am really wondering if the slowing Atlantic gulf stream is going to bounce back or continue to decline. The weather has become odd in recent years. That circulation takes warm water to the north pole so one prediction would be a cooling there and recovery of the ice cover with about a twelve year lag due to the ocean heat store. That would be a feed back stabilising the European cooling effect although a cooling trend seems to be happening.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    There is an Oyashio cold current into the north pacific current that ends up travelling down the usa west coast. It is equivalent i guess to the cold greenland current that powers the gulf stream. So if there is that cooling from artic waters, maybe there is a link. It is not one i can find reported but it could be part of the global picture. Fewer tornados might be welcome but colder weather here not so much.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by geonuc View Post
    I don't know the answer to your question but I don't think AMOC is synonymous with Gulf Stream. The latter is part of the former. Your linked article uses the term Gulf Stream System.
    I agree. I modified the thread title.

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    Quote Originally Posted by grapes View Post
    I agree. I modified the thread title.
    With further reading maybe we should alter the title more because i read that the AMOC is thermodyhamic and density driven while the gulf syream system is wind driven. So they are different and i had not appreciated that through reading journalistic reports. The former is a deep cold current and the latter a surface warm current, (getting cooler at present). It is the change in the density through melt water that may be important while a wind driven flow is harder to understand as a long term diminishing current. The accelerating decline remains alarming for Europe and possibly the East coast USA. The Oshiyo current is not apparently changing in the same way although i believe it is a bigger scale current around Japan and influencing the north pacific warm current. So far i cannot find figures for the up to date Oshiyo temperatures and they would be interesting in this context.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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    Quote Originally Posted by profloater View Post
    With further reading maybe we should alter the title more because i read that the AMOC is thermodyhamic and density driven while the gulf syream system is wind driven. So they are different and i had not appreciated that through reading journalistic reports. The former is a deep cold current and the latter a surface warm current, (getting cooler at present). It is the change in the density through melt water that may be important while a wind driven flow is harder to understand as a long term diminishing current. The accelerating decline remains alarming for Europe and possibly the East coast USA. The Oshiyo current is not apparently changing in the same way although i believe it is a bigger scale current around Japan and influencing the north pacific warm current. So far i cannot find figures for the up to date Oshiyo temperatures and they would be interesting in this context.
    The Gulf Stream is wind driven?

    Regardless, there's probably a distinction between Gulf Stream and Gulf Stream System. That article says
    The Atlantic Meridional Overturning Circulation (AMOC, also known as Gulf Stream System)
    I wouldn't completely discount it as a journalist report, the writer seems to be one of the authors of the Nature articles:
    Let’s start with tomorrow’s issue of Nature, which besides the two new studies (one of which I was involved in)

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    Quote Originally Posted by grapes View Post
    The Gulf Stream is wind driven?
    Britannica (https://www.britannica.com/place/Gulf-Stream) says:
    Most of the waters that enter the Gulf Stream system first have been driven westward across the Atlantic by the Northeast Trade Winds.

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    I was surpised by that also, another complexity, the wind also being warmed and wetted in the interaction. A cooler weaker gulf stream, a cooler drier wind system, is that the model? The Uk land mass is warming, many biological markers are evidence. But it is consistent that land masses can be warmed while sea currents cool. The prognostication is not so easy to pin down.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

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