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#1433948 - 13/09/2017 20:50 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
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Registered: 10/08/2017
Posts: 1396
Loc: Wollongong, NSW, Aus
Originally Posted By: ColdFront
Originally Posted By: Mike Hauber
The atmosphere is driving the cooling in the Pacific.


Probably not entirely on its own. The cooling has not all originated west to east propagation of a kelvin wave as shown in the cut aways. There is likely to be a contribution from currents in the South Pacific Gyre also bringing cold water from the southern hemisphere upwelling along the equator.

NOAA's maps seem to support this.

Ultimately according to a recent documentary I watched , the deep waters off Antarctica drive the lot.


I agree with you - I reckon the ocean is driving the atmosphere hence the lag and the rapid transition.

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#1433953 - 13/09/2017 21:50 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Pooraka Offline
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Quote:

Ultimately according to a recent documentary I watched , the deep waters off Antarctica drive the lot.


What documentary is that out of curiosity? Sounds like it could be a good one to watch.


Edited by Pooraka (13/09/2017 21:50)

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#1433955 - 13/09/2017 23:11 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Pooraka]
ColdFront Offline
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Registered: 29/06/2008
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Originally Posted By: Pooraka

Quote:

Ultimately according to a recent documentary I watched , the deep waters off Antarctica drive the lot.


What documentary is that out of curiosity? Sounds like it could be a good one to watch.


I've tried to search for it tonight to no avail. I watched it a few months back. I believe it may have been in the "forces of nature" series but can't be certain. I'll try again over coming days.
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#1433964 - 14/09/2017 07:13 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Colin Maitland Offline
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There was also a Documentary on the BBC about the Whirlpools or Maelstroms around the world that help this conveyor belt working. It included Corryvreckan in Scotland, one of the largest whirlpools. I have it on tape and it used to be on google but cant find it.




The Great Ocean Conveyor Belt - The blue color represents the deep cold and saltier water current with the red color indication shallower and warmer current.
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#1434023 - 14/09/2017 15:49 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ColdFront Offline
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Yeah that conveyor was mentioned in the doco.

Sent you a PM Pooraka.
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#1434025 - 14/09/2017 16:05 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
GringosRain Offline
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conveyor conveniently doesnt go up the west coast of south America? Its a key region and that simple drawing doesnt show anything going on in the east pacific. Im guessing in reality that blue line runs right over to the tip of south America and pushes north?

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#1434027 - 14/09/2017 16:18 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
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Loc: Wollongong, NSW, Aus
Here are the surface currents:



And the thermohaline:



Interesting that the cold waters start at Antarctica before upwelling right in the ENSO zones....so what Coldfront was saying/watched definitely has some link to ENSO.


Edited by Kino (14/09/2017 16:25)

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#1434028 - 14/09/2017 16:21 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
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Loc: Wollongong, NSW, Aus
And this is a different perspective of the Thermohaline:


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#1434030 - 14/09/2017 16:58 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
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Registered: 10/08/2017
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Loc: Wollongong, NSW, Aus
Fascinating:

Quote:
According to NOAA It takes almost a 1000 years to complete a cycle. I am not sure how accurate, or where the citation came from their information so take it with a grain of salt. Lecture notes from one of Columbia University's 2007 "The Climate System" class suggests this process takes between 100-1000 years. This paper says Thermohaline Circulation overturns deep water every 600 years or so.

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#1434031 - 14/09/2017 17:52 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
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Registered: 10/08/2017
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Loc: Wollongong, NSW, Aus
So, could ENSO actually be a 100-year; 600-year or even 1000-year cycle!!???


Edited by Kino (14/09/2017 17:53)

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#1434034 - 14/09/2017 18:10 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
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Registered: 10/08/2017
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Loc: Wollongong, NSW, Aus
Seems I'm yapping to myself, but I'll continue always lol

So, there are plenty of papers that speculate that sea water density also affects ENSO, specifically fresh water that impacted ENSO back in the mid 2000's (for the geeks there's one at http://journals.ametsoc.org/doi/full/10.1175/JCLI3495.1 ).

Now, the northern arm of the Thermohaline circulates through the Gulf of Mexico. Given the recent Hurricane activity in both Texas and Florida, I wonder how that denser water will interrupt / impact the Thermohaline? That paper seems to suggest it may.


Edited by Kino (14/09/2017 18:14)
Edit Reason: spellunk

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#1434045 - 14/09/2017 20:10 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mad Elf #1.5 Offline
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Registered: 05/03/2012
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No Kino, I & many others are reading.
Keep going mate, very interesting.

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#1434048 - 14/09/2017 20:33 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
Seira Offline
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Registered: 27/08/2003
Posts: 7214
Loc: Adelaide Hills.
Originally Posted By: Kino
Given the recent Hurricane activity in both Texas and Florida, I wonder how that denser water will interrupt / impact the Thermohaline? That paper seems to suggest it may.

The possibility of abrupt climate change due to changes in the deep circulation of the north Atlantic was first proposed by Wallace Broecker of the Lamont-Doherty Observatory of Columbia University. He is the one who wrote:

“…it is clear that Earth's climate system has proven itself to be an angry beast. When nudged, it is capable of a violent response.” From: Broecker (2003).

Analysis of many different types of data collected throughout the world has shown that climate can change abruptly. The record is roughly 6 C in 1 – 3 years recorded in Greenland ice cores (Steffensen et al 2008) and in a core through sediments in a German lake (Brauer et al 2008).


Edited by Seira (14/09/2017 20:33)
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#1434049 - 14/09/2017 20:40 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
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Loc: Wollongong, NSW, Aus
Indeed Siera...it's happened in the past and will continue to do so.

There is a pretty detailed paper on the interactions between fresh water, Atlantic current and ENSO (here for the geeks: http://onlinelibrary.wiley.com/store/10....f5be1da3d8c500a. The initial analysis shows a significant link between them.



However; when they look back 120K years, to my untrained eye, it appears as there is some sort of cyclical signal in the data (not discussed or addressed in the paper - they seemed more intent on blaming the usual suspect...):



Now - what is not apparent to me is - is the fresh water impacting ENSO OR ENSO causing the fresh water.

That is ENSO -- heats water - water melts --- fresh water injected into Thermohaline - Thermohaline impacts ENSO -- ENSO cools - ICE builds - less dense water injected into Thermohaline - ENSO warms again etc and cycle continues.


Edited by Kino (14/09/2017 20:43)

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#1434050 - 14/09/2017 20:52 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Seira]
Kino Offline
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Registered: 10/08/2017
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Loc: Wollongong, NSW, Aus
Originally Posted By: Seira
Originally Posted By: Kino
Given the recent Hurricane activity in both Texas and Florida, I wonder how that denser water will interrupt / impact the Thermohaline? That paper seems to suggest it may.

The possibility of abrupt climate change due to changes in the deep circulation of the north Atlantic was first proposed by Wallace Broecker of the Lamont-Doherty Observatory of Columbia University. He is the one who wrote:

“…it is clear that Earth's climate system has proven itself to be an angry beast. When nudged, it is capable of a violent response.” From: Broecker (2003).

Analysis of many different types of data collected throughout the world has shown that climate can change abruptly. The record is roughly 6 C in 1 – 3 years recorded in Greenland ice cores (Steffensen et al 2008) and in a core through sediments in a German lake (Brauer et al 2008).


Yeah, the paper I read & quoted pre-dates both of these papers (2002), but does align (with the usual "what-cannot-be-named" flavour running though it sadly).

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#1434051 - 14/09/2017 21:01 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
Kino Offline
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Registered: 10/08/2017
Posts: 1396
Loc: Wollongong, NSW, Aus
Originally Posted By: Kino
Indeed Siera...it's happened in the past and will continue to do so.

There is a pretty detailed paper on the interactions between fresh water, Atlantic current and ENSO (here for the geeks: http://onlinelibrary.wiley.com/store/10....f5be1da3d8c500a. The initial analysis shows a significant link between them.



However; when they look back 120K years, to my untrained eye, it appears as there is some sort of cyclical signal in the data (not discussed or addressed in the paper - they seemed more intent on blaming the usual suspect...):



Now - what is not apparent to me is - is the fresh water impacting ENSO OR ENSO causing the fresh water.

That is ENSO -- heats water - water melts --- fresh water injected into Thermohaline - Thermohaline impacts ENSO -- ENSO cools - ICE builds - less dense water injected into Thermohaline - ENSO warms again etc and cycle continues.


Looking again at these graphs with an untrained eye; IF fresh water was impacting ENSO surely the salinity would dip before ENSO and not at the same time? There'd be a lag period etc as the denser water was transported along the Thermohaline. Whereas i would have thought if ENSO was the cause of the fresh water the impact would be around the same time or slightly after ENSO?

And by ENSO I would suspect it would be Nina that would be the driver re Atlantic as we know it pushes the warmer waters west; and allows higher pressure over western USA etc?

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#1434054 - 14/09/2017 21:42 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
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And this....(from here http://oceanmotion.org/html/impact/conveyor.htm ignore the Voldamort references...)

Quote:
Ocean circulation is comprised of a global network of interconnected currents, counter-currents, deepwater currents, and turbulent eddies. From this complex circulation, an underlying transport pattern emerges. Water cycles from surface currents to deepwater currents then back to the surface again in what scientists liken to a giant conveyor belt. Scientists call this global conveyor belt the meridional overturning circulation.

There are two major forces driving the meridional overturning circulation. First there is the wind. The wind, in combination with the Earth’s rotation, generates the gyres that circle the major ocean basins. Turbulent swirling packets of water called eddies, many of which are hundreds of kilometers in diameter, spin out of these wind-driven currents and carry the water trapped inside them to other parts of the ocean.

The second force is tied to differences in the density of water. Temperature and salinity independently affect water’s density. The colder and saltier the water, the denser it becomes. As water becomes denser, it sinks.

This is where the Atlantic Ocean plays a pivotal role. Again, the Gulf Stream and the North Atlantic Current carry warm salty tropical water up into the Labrador and Greenland Seas. Frigid Arctic winds cool this water, increasing its density. The water then sinks, feeding deepwater currents. This same density driven creation of deepwater also takes place in the frigid Ross and Weddell Seas off the coast of Antarctica, and to a lesser extent in the salty Mediterranean Sea.

Scientists call this density-driven component of the meridional overturning circulation the thermohaline circulation; thermo meaning heat and saline meaning salt. Without this density-driven process, deepwater currents would no longer be created. The global conveyor belt would grind to a halt.

Scientists are using observations and models to trace the complex pathways of the meridional overturning circulation and determine its strength. It’s an overwhelming task. Maps charting the circulation’s course are still evolving. Deeper currents and upwelling in particular are extremely difficult to measure. But some patterns are becoming clearer.

Starting off the Greenland coast, the newly created deepwater slowly drifts south along the western margin of the Atlantic basin. It then crosses the equator and mixes with the deepwater currents circling Antarctica. Models suggest that some of this water resurfaces in this area. Much of it, however, spreads north into Indian and Pacific Oceans where it mixes with warmer water and resurfaces.

To close the loop of the conveyor belt, surface water flows from the Pacific and Indian Oceans back into the South Atlantic then heads north. Some cold water enters the South Atlantic from the Pacific around the southern tip of South America. The Agulhas Current in the Indian Ocean is another important source. This fast-moving current, the Indian Ocean’s equivalent of the Gulf Stream, flows down the southeast coast of Africa and past the tip of South Africa then takes a sharp turn to the east. Large eddies called Agulhas Rings spin off this bend and carry huge bundles of warm salty Indian Ocean water west into the South Atlantic. Currents carry much of this Indian Ocean water north to the equator where the sun heats it further. Eventually this water enters the Caribbean and is swept into the Gulf Stream.

Scientists believe that these Agulhas Rings are critical sources of the salty water that drives the formation of deep water up north. Eddies spinning out of the Mediterranean Sea and net evaporation in the tropical Atlantic also contribute salty water.

Despite its enormous scope, the meridional overturning circulation is vulnerable. Places where deepwater currents are created comprise less than one percent of the ocean’s surface area. Should the temperature or salinity in these limited areas change, the creation of deep water could slow or even stop.

There is strong evidence that such a shutdown has happened in the past, drastically altering the world’s climate in just a matter of years. Eleven thousand years ago, ice age glaciers were retreating. In central Canada, an immense glacial lake called Lake Agassiz occupied an area larger than all the Great Lakes. Suddenly the dams holding Lake Agassiz collapsed. The contents of the entire lake rushed into the North Atlantic by way of the St. Lawrence River. This massive infusion of fresh water diluted the polar seas to the point where the water was no longer dense enough to sink. The meridional overturning circulation likely ground to a stop. Called the Younger Dryas, this one thousand year period saw the temporary return of the ice age.


So...is it the air that drives the climate or the sea...is ENSO responsible for ice ages? Is the great driver of climate the antarctic circumpolar current?


Edited by Kino (14/09/2017 21:45)

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#1434055 - 14/09/2017 21:54 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Seira Offline
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Registered: 27/08/2003
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The ENSO may impact the thermohaline circulation if it has very long-term cycles that are not of the well-known 4-7-year origin; however, none of ENSO-THC-ENSO-THC would be possible without equatorial or polar evaporation, causing changes in wind-stress and wind direction, leaving cooler salty water behind to upwell and mix. The other thing is water has a much higher heat-capacity than air.

If you can get access to it there is a 3D plot of the THC seen from the South Pole Perspective from Aguado and Burt, Understanding Weather and Climate.


Edited by Seira (14/09/2017 21:58)
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#1434057 - 14/09/2017 21:58 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Seira]
Kino Offline
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Registered: 10/08/2017
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Originally Posted By: Seira
The ENSO may impact the thermohaline circulation if it has very long-term cycles that are not of the well-known 4-7-year origin; however, none of ENSO-THC-ENSO-THC would be possible without equatorial or polar evaporation, causing changes in wind-stress and wind direction, leaving salty water behind to upwell and mix. The other thing is water has a much higher heat-capacity than air.

If you can get access to it there is a 3D plot of the entire THC seen from the South Pole Perspective from Aguado and Burt, Understanding Weather and Climate.


You missed my point - I speculated that ENSO is responsible for those effects.

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#1434058 - 14/09/2017 22:20 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
Seira Offline
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Registered: 27/08/2003
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Loc: Adelaide Hills.
Originally Posted By: Kino
Originally Posted By: Seira
The ENSO may impact the thermohaline circulation if it has very long-term cycles that are not of the well-known 4-7-year origin; however, none of ENSO-THC-ENSO-THC would be possible without equatorial or polar evaporation, causing changes in wind-stress and wind direction, leaving salty water behind to upwell and mix. The other thing is water has a much higher heat-capacity than air.

If you can get access to it there is a 3D plot of the entire THC seen from the South Pole Perspective from Aguado and Burt, Understanding Weather and Climate.


You missed my point - I speculated that ENSO is responsible for those effects.

I may have missed the point because I take longer the consider my response...or I realised you said you were speculating, hence the caution.

Regarding this:

Originally Posted By: Kino
So...is it the air that drives the climate or the sea...is ENSO responsible for ice ages? Is the great driver of climate the antarctic circumpolar current?

Heat transport would be a big factor, and the energy balance at the edge of space.

I can't really conclusively answer all the questions because (a) I don't know or (b) research doesn't addressing certain aspects.

We're in a relatively cool period now; we have polar ice caps.
I can point to Shackleton & Kennet, 1975 and Moore et al., 1987 for that smile .


Edited by Seira (14/09/2017 22:22)
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