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Post by icefisher on Sept 22, 2012 1:14:35 GMT
"Negative feedback does not exist, therefore you must be wrong, and ridiculed for your blasphemy" Well as I said, apparently this supposed negative feedback won't work here to the effect some people HOPE it would, and we have the ice continuing to melt!
Sorry folks, it's a no recovery no summer ice situation we have at hand here. As some always say, it's nothing new in the Arctic, and probably something entirely natural ....
Unfortunately its completely unpredictable. A thousand expert scientists failed to match the ice loss with every model run they tried. In fact the actual forces in play are so poorly understood its even impossible to say if they are still in place, reversed, or went into neutral some time ago. YOUR CHART: Who knows? Probably when the modelers adjust their models to track observations the observations will reverse direction. Such is the kind of frustration that is typical of cutting edge science. And its good to know that when they do get it right testing it for another 17 years is a minimal standard for climate. Thus any certainty from modeling climate is impossible to achieve via current official standards before 2030. Could even be the same natural cause that is fast melting the glaciers in the Alps ... Got that. . . .for the last 200 to 300 years. |
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Post by icefisher on Sept 23, 2012 0:43:26 GMT
"The arctic ocean has an average depth of over 1000m"
The average depth of the Earth's oceans is 3790 meters.
"There is a halocline"
Goodness, and how much has it got to do with temperature? The important thing to note that while the Arctic is a relatively shallow ocean, it is much deeper than the thermocline. I think the above diagram is way over simplified. The halocline is more limited than the thermocline. Upper ocean mixing is done by storms and tides and these effects seldom reach much beyond 20 meters. So the well mixed zone is 20 meters deep. The rule of thumb is swell height in a storm is one half of the disturbance zone so you would find a gradient to twice 20 meters or 40 meters. The thermocline is also affected by storms and tides but it has one more vehicle and that is the fact sunlight on average penetrates 200 meters into the ocean. www.enchantedlearning.com/biomes/ocean/sunlit/This zone is called the euphotic zone. Here is a comparison of the thermocline and halocline. As you can see both start a gradient at the 20 meters of well mixed zone. However, the top diagram shows what appears to be a halocline extending to 200 meters. This may be incorrect. (correct for the thermocline but not the halocline) Here is a sample halocline and thermocline that makes more sense.  As you can see the halocline is well mixed to 20 meters and extends to 40 meters. The thermocline extends from 20 meters to the bottom of the graph. When you are below 100 meters very little light penetrates so the thermocline is becoming very small beyond that depth and goes extinct when light becomes extinct. In murky water the extinction level can be much less. For ice covered water the halocline would be much less also as the big driver halocline depth is storm winds creating ocean swells. So I have to wonder what the physical driver is for the so-called arctic halocline at 200 meters as in the above diagram. Its also important to note that ocean currents move along fairly rapidly at the surface. Thus water exchanges between the arctic and the north atlantic comes from a lot more than just salt falling from ice as depicted in the above diagram. Oddly the diagram is only referenced to Jayne Doucette, Graphics Manager in the Graphics Department at WHOI as opposed to a study about the halocline by an expert. "The earths total heat content is unknown"Only a very small fraction comes from the Earth itself. I'd be very worried if it had actually changed a bit in a million years.
People have actually studied the flow: psc.apl.washington.edu/zhang/Pubs/zhang5_15_98.pdf
The Arctic Ocean is massive, but so are the currents. I can't imagine you Mr Iceskaters shoud be so ignorant of this, surely having witnessed the daily sea ice motion this summer. These are no kid pools.
Huh? What the heck are you talking about? Earth's heat content changes as the surface changes. The surface the sun is shining on changes every hour. The seasons bring cloud, snow, and ice changes. and the southern hemisphere has a different mix of land and sea than the NH. And you are concerned about this? What the heck are you talking about?
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Post by numerouno on Sept 23, 2012 2:48:11 GMT
" What the heck are you talking about?"
See you again in summer 2013!
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Post by Andrew on Sept 23, 2012 7:18:40 GMT
So I have to wonder what the physical driver is for the so-called arctic halocline at 200 meters as in the above diagram.
and in the Nansen Basin, respectively. Both temperature and salinity
at 180m and 250m depths clearly increase from the Amundsen Basin
through the AMOR to the Nansen Basin.The halocline is caused by a combination of salt descending by freezing of salt water, plus fresh water flow into the arctic basin from precipitation Any partially land locked sea is going to tend to be a lake rather than fully salt water because the heavier salt water does not easily push against the outwards flow of lighter fresh water. An extreme land locked sea is the baltic sea and the black sea must be an even more extreme example. Water at the sea shore in Southern Finland is hardly salty at all compared to the water around New Zealand - a small island in a huge sea. |
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Post by icefisher on Sept 23, 2012 15:06:45 GMT
So I have to wonder what the physical driver is for the so-called arctic halocline at 200 meters as in the above diagram.
and in the Nansen Basin, respectively. Both temperature and salinity
at 180m and 250m depths clearly increase from the Amundsen Basin
through the AMOR to the Nansen Basin.The halocline is caused by a combination of salt descending by freezing of salt water, plus fresh water flow into the arctic basin from precipitation Any partially land locked sea is going to tend to be a lake rather than fully salt water because the heavier salt water does not easily push against the outwards flow of lighter fresh water. An extreme land locked sea is the baltic sea and the black sea must be an even more extreme example. Water at the sea shore in Southern Finland is hardly salty at all compared to the water around New Zealand - a small island in a huge sea. thanks for the link that's a nice source. Your comment "because the heavier salt water does not easily push against the outwards flow of lighter fresh water." Cold freshwater should run like a river out of the arctic while warm Atlantic salty water runs at depth under it. The warm salty Atlantic water should push from the force of gravity into the arctic. The fact there are fronts (salinity or otherwise) at bottom topography features is not unique to salinity differences. Bottom topography creates current breaks that creates the same kind of fronts between waters of different color. The salinity differences between tropic waters and arctic waters I presume is due to evaporation in the tropics being a more robust salting process than salt falling out of ice. So I am guessing that this deeper halocline (and perhaps its not a halocline at all in the traditional sense) is instead some kind of mixing zone between atlantic and arctic water. According to halocline chart (taken in the tropics) I posted above there is no halocline at the equator below 40 meters. Dynamic processes are indeed complex. The pdf is interesting and when I have a bit more time I intend to study it more carefully but I did see this:
In order to understand the variability of the Arctic Ocean and its
role to the climate change, we have been carrying out ice-drifting
buoy (J-CAD) observations in collaboration with NPEO project since
2000. Observational results during 2000-2002 clearly present a
continuation of an increase in surface salinity and warming of the
Atlantic water in the Amundsen Basin. However, some recent articles
reported a recovery of the cold halocline in the Amundsen Basin.
What is the difference between them?So what is this? A temperature cycle in the arctic? Is it multi-decadal in nature? The water at depth has only recently reversed direction towards getting colder after getting warmer throughout the entire earlier data record? Stay tuned! |
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Post by sigurdur on Sept 23, 2012 20:34:05 GMT
Icefisher:
There is a well known current change/cycle in the Arctic. I don't have time right now, but I will dig and find papers talking/showing this.
In fact, that current/change cycle has a name, but I can't remember it right of the top of my head. I must be getting older.....phew......a good thing. LOL.
The effect of less ice in the Arctic is actually negative feedback. The thing to watch for this winter is any sudden stratospheric cooling periods. When this happens, a HUGE amount of earths heat is quickly shed to outer space. I don't remember how long it takes to recover that heat loss, but it is far longer than a few months.
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Post by douglavers on Sept 23, 2012 22:47:20 GMT
I think I understand and agree with what Sigurdur is saying. ocean.dmi.dk/arctic/meant80n.uk.phpLooking at the nearly vertical downward trend in the graph, and bearing in mind the vast ice creation process which is now occurring in the Arctic, an enormous amount of heat is exiting the planetary system as radiation during the Arctic night. This is aided by the large area of [relatively] warm unfrozen water surface. Of course, this will only go on for another month or so, after which most of the Arctic will be frozen; ice melting panic over for another year. Perhaps the level of Summer Arctic Ice melt is actually trivial. I suspect that when the planetary ice control process is really understood, large Summer storms such as occurred in the Arctic Ocean in August will be seen as major net cooling events. |
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Post by thermostat on Sept 24, 2012 1:34:35 GMT
I think I understand and agree with what Sigurdur is saying. ocean.dmi.dk/arctic/meant80n.uk.phpLooking at the nearly vertical downward trend in the graph, and bearing in mind the vast ice creation process which is now occurring in the Arctic, an enormous amount of heat is exiting the planetary system as radiation during the Arctic night. This is aided by the large area of [relatively] warm unfrozen water surface. Of course, this will only go on for another month or so, after which most of the Arctic will be frozen; ice melting panic over for another year. Perhaps the level of Summer Arctic Ice melt is actually trivial. I suspect that when the planetary ice control process is really understood, large Summer storms such as occurred in the Arctic Ocean in August will be seen as major net cooling events. douglavers, In looking at the historical DMI temperature graphs for the arctic, it is useful to click back through the past 10 to 20 years to get a useful sense of the historical data. You wrote,"Looking at the nearly vertical downward trend in the graph, and bearing in mind the vast ice creation process which is now occurring in the Arctic, an enormous amount of heat is exiting the planetary system as radiation during the Arctic night." That is correct, in a similar manner to all of the recent years with reduced minimal sea ice extent. Similar heat was also leaving the system then, especially over the past 10 years. Also, take into account those graphs from the last 10-20 years. A lot of the variation one sees here is due to weather. Weather is also a factor at the present time. Overall, the fundamental effect of this phenomenon is to delay freezing in the arctic and increase arctic surface temperatures in the Fall and Winter. Together, these effects feed back and reduce the volume of ice formed during the freezing season. (consider; the 'vast amount of heat' now entering the arctic atmosphere that never used to be there.) You also wrote, "Perhaps the level of Summer Arctic Ice melt is actually trivial." The Sea Ice extent affects the addition of heat to the system via the albedo effect, but the sea ice volume is the real key. fyi, the large summer storm was actually induced by ongoing warming. The storm had the effect of pulling heat into the arctic. It was another example of ongoing arctic amplification. |
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Post by thermostat on Sept 24, 2012 1:46:32 GMT
Just a short comment, the fundamental notion that melting the Arctic Sea Ice cools the earth is fundamentally contrary to our understanding of the recent Ice Ages. In particular, such a notion fundamentally challenges the present mechanisms that explain the Pleistocene. I would be most curious to hear a plausible mechanism that could explain this contradiction.
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Post by magellan on Sept 24, 2012 2:21:21 GMT
Just a short comment, the fundamental notion that melting the Arctic Sea Ice cools the earth is fundamentally contrary to our understanding of the recent Ice Ages. In particular, such a notion fundamentally challenges the present mechanisms that explain the Pleistocene. I would be most curious to hear a plausible mechanism that could explain this contradiction. You still need to explain the "more rapid warming of the 20's and 30's" than CWP. That's #1. You seem to avoid that inconvenient observation. Your standard response has been to mock natural cycles as mythical. Do you still hold that view? I ask because in 2009 at a UN conference a top climate modeller, who is not a "denialist" said this: www.newscientist.com/article/dn17742-worlds-climate-could-cool-first-warm-later.html?full=true&print=true"cycles", "cold phase". Sound familiar? I thought it was already determined cycles and phases were a thing of the past, or in your words, mythical. |
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Post by thermostat on Sept 24, 2012 2:27:20 GMT
Just a short comment, the fundamental notion that melting the Arctic Sea Ice cools the earth is fundamentally contrary to our understanding of the recent Ice Ages. In particular, such a notion fundamentally challenges the present mechanisms that explain the Pleistocene. I would be most curious to hear a plausible mechanism that could explain this contradiction. You still need to explain the "more rapid warming of the 20's and 30's" than CWP. That's #1. You seem to avoid that inconvenient observation. Your standard response has been to mock natural cycles as mythical. Do you still hold that view? I ask because in 2009 at a UN conference a top climate modeller, who is not a "denialist" said this: www.newscientist.com/article/dn17742-worlds-climate-could-cool-first-warm-later.html?full=true&print=true"cycles", "cold phase". Sound familiar? I thought it was already determined cycles and phases were a thing of the past, or in your words, mythical. Magellan wrote "You still need to explain the "more rapid warming of the 20's and 30's" than CWP." You got me with your jargon here. Could you state that question in plain english? |
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Post by thermostat on Sept 24, 2012 2:30:59 GMT
Regarding the question of whether arctic sea ice melting would create a negative feedback, physics indicates the opposite. ie. increased arctic melting results in a positive feedback.
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Post by magellan on Sept 24, 2012 4:11:46 GMT
You still need to explain the "more rapid warming of the 20's and 30's" than CWP. That's #1. You seem to avoid that inconvenient observation. Your standard response has been to mock natural cycles as mythical. Do you still hold that view? I ask because in 2009 at a UN conference a top climate modeller, who is not a "denialist" said this: www.newscientist.com/article/dn17742-worlds-climate-could-cool-first-warm-later.html?full=true&print=true"cycles", "cold phase". Sound familiar? I thought it was already determined cycles and phases were a thing of the past, or in your words, mythical. Magellan wrote "You still need to explain the "more rapid warming of the 20's and 30's" than CWP." You got me with your jargon here. Could you state that question in plain english? You are a self proclaimed expert and don't know what CWP is? Look it up. This is getting repetitious because nearly everything being posted was done prior to the original Arctic thread being deleted. Are you denying the period prior to 1940 didn't warm as fast or faster than the last 30-40 years? What natural cycle (you call them myths) caused the rapid warming in the first half of the 20th century that can't explain the current period (1979-2012), which you seem to think comprises all of Arctic history and anything previous to 1979 is folklore. Wash, rinse, repeat. |
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Post by magellan on Sept 24, 2012 4:22:34 GMT
www.agu.org/pubs/crossref/2006/2006GL026510.shtmlWe provide an analysis of Greenland temperature records to compare the current (1995–2005) warming period with the previous (1920–1930) Greenland warming. We find that the current Greenland warming is not unprecedented in recent Greenland history. Temperature increases in the two warming periods are of a similar magnitude, however, the rate of warming in 1920–1930 was about 50% higher than that in 1995–2005.
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Post by magellan on Sept 24, 2012 4:23:49 GMT
meteo.lcd.lu/globalwarming/Chylek/greenland_warming.htmlTo summarize, we find no direct evidence to support the claims that the Greenland ice sheet is melting due to increased temperature caused by increased atmospheric concentration of carbon dioxide. The rate of warming from 1995 to 2005 was in fact lower than the warming that occurred from 1920 to 1930. The temperature trend during the next ten years may be a decisive factor in a possible detection of an anthropogenic part of climate signal over area of the Greenland ice sheet.
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