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Post by missouriboy on Dec 28, 2015 23:48:08 GMT
We should thank Nautonnier for that link. So now that they're getting some quantitative heat data ... how long till some sharp fellows can tell us how this affects ocean temperatures in various locations under various assumptions? Can it heat the East Greenland Sea???
"the vents release over a one thousand kilograms per second of fluid at 215°C, which carries hundreds of megawatts of heat out of the crust."
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Post by acidohm on Dec 30, 2015 21:16:17 GMT
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Post by missouriboy on Dec 30, 2015 22:48:53 GMT
Most people (including myself) don't have a clue as to how big this "cup" actually is. So ... when we ask the next question ... "How much ice would we have to melt to lower the temperature of the upper 700 meters of the North Atlantic Ocean by let's say 0.5 degrees C ? What would that answer be??? And would it be in the range of what we've seen happen in the Arctic (including Greenland) over the last, let's say, 15 years? Or 10 years? Yes, that does not account for the atmospheric transfer component of heat loss ... assuming it's been negative for a short while. Where are our mathematicians? Who wants to step up to that problem?
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Post by sigurdur on Dec 30, 2015 23:18:37 GMT
Most people (including myself) don't have a clue as to how big this "cup" actually is. So ... when we ask the next question ... "How much ice would we have to melt to lower the temperature of the upper 700 meters of the North Atlantic Ocean by let's say 0.5 degrees C ? What would that answer be??? And would it be in the range of what we've seen happen in the Arctic (including Greenland) over the last, let's say, 15 years? Or 10 years? Yes, that does not account for the atmospheric transfer component of heat loss ... assuming it's been negative for a short while. Where are our mathematicians? Who wants to step up to that problem? Whoa......that one would take some WORK! And I don't think the slight net negative loss of ice is enough to materially affect the OHC of the area. Think of how much water is ACTUALLY there. Kinda like putting a cup of cold water into a bathtub full of water @110.F.
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Post by sigurdur on Dec 30, 2015 23:19:50 GMT
And I am talking about the old crow foot cast iron bathtub that held 100+gallons of water!
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Post by missouriboy on Dec 31, 2015 2:14:05 GMT
Most people (including myself) don't have a clue as to how big this "cup" actually is. So ... when we ask the next question ... "How much ice would we have to melt to lower the temperature of the upper 700 meters of the North Atlantic Ocean by let's say 0.5 degrees C ? What would that answer be??? And would it be in the range of what we've seen happen in the Arctic (including Greenland) over the last, let's say, 15 years? Or 10 years? Yes, that does not account for the atmospheric transfer component of heat loss ... assuming it's been negative for a short while. Where are our mathematicians? Who wants to step up to that problem? Whoa......that one would take some WORK! And I don't think the slight net negative loss of ice is enough to materially affect the OHC of the area. Think of how much water is ACTUALLY there. Kinda like putting a cup of cold water into a bathtub full of water @110.F. Yeah ... that was kinda what I was thinking. So I just used the already converted figures in the article for Greenland ... 8165 km3 ... equals 8,165,000,000 m3 ... or 8,165,000 m2 x 1 m thick ... divided by 2,590,000 m2 per mile2 equals 3.15 sq. miles. So 1 m3 of meltwater at 0 C would lower 20 m3 of 10C water by 0.5 C. Therefore, all ice lost from Greenland in the 20th century would lower approx. 60 sq. miles of ocean water one meter thick at 10 C by 0.5 C. Therefore, if my calculations are correct, then melting all the ice on Greenland would increase this area by 333 (100% / 0.3%) would only amount to about 20,000 sq. miles at 1 meter thick. Given there are about 20,000,000 sq. miles of area in the North Atlantic, it seems safe to say that temperature drops of 0.5 C, as those claimed to have occurred during the last negative AMO could likely not be accomplished by melting ice. So unless these back-of-the-envelope calculations are oft by 2 or 3 orders of magnitude, even the melting of all of Greenland and the entire Arctic Ocean (~5 million sq. miles) would not accomplish this task. I feel better now! Of course the heat released by water in the task of melting ice would also have an effect I guess.
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Post by sigurdur on Dec 31, 2015 3:54:38 GMT
I see nothing wrong with your calculations. I was thinking of ice volume actually shed by Greenland on an annual basis, did a quick mental calc.....and thought.....not significant.
You proved it you sharp feller!
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Post by buildreps on Dec 31, 2015 3:58:33 GMT
That's not so easy to answer indeed. You'll need a whole range of more data to answer that question, but if you want to have a first shot, you did it quite well Better use Kelvin instead of Celsius, it's much easier. Let's neglect the mixing effects between sweet and salt water, and the salt secretion when the whole ocean drops a 0.5K in temperature. Just an example (20*283+1x273)/(20+1)=282.5K The vertical temperature gradient of the Atlantic between 0 and 700 meters will resp. go from 283K to just above freezing point I guess. Let's say it's average 278K. To cool that volume of the Atlantic (A = 106,400,000km2 * 0.7km = 7.448×10⁷ km3) with a 0.5K would require like the example of above (A*278+B*273)/(A+B)=277.5K. Simplifying this formula results in 0.5A=4.5B. So, B is 9 times smaller than A. B=8.3×10⁶ km3. It looks like that's the whole Greenland ice sheet. Am I right?
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Post by sigurdur on Dec 31, 2015 5:12:56 GMT
If I get a chance I will check your post tomorrow. Need to be in my office. Looks good initially tho!
Thanks for what you presented!
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Post by sigurdur on Dec 31, 2015 5:15:26 GMT
Doing it in my head, looks like you are spot on!!
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Post by missouriboy on Dec 31, 2015 6:06:11 GMT
Just occurred to me that I may have destroyed my number one answer for the increasing volumes of cold water moving down the Labrador Current and interfering with the NAD ... not to mention the temperature changes (-0.5 to -1.5 C) that are occurring, according to Argo at depths of 0-700 meters (and below with smaller temp changes) in the North Atlantic. These are occurring to very large quantities of water north of about 45 N latitude. So, if ice melt is not contributing a large portion of this cooling, then what the hell is? Is loss of heat to atmospheric warming so dramatic, that with little warm recharge, that alone (largely) could account for all this water cooling in the N. Atlantic at depth? I have not calculated the volumes of water we are talking about, but they are very large. Increasing salinity in the northeastward moving expansion eddy of cooling water keeps the leading edges subducting back to the southeast (and perhaps the northwest as well?). We have seen this in previous Argo sections. Winds and the Coriolis effect keep the sub-polar gyre operating but the amount of warm water appears to be dwindling. Is it now feeding largely on itself??? and becoming colder and colder??? Shooting from the hip here. We do know however that in select years after 2007, large quantities of cold water have crossed the subtropical gyre and cooled the Sargasso Sea.
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Post by missouriboy on Dec 31, 2015 7:16:29 GMT
That's not so easy to answer indeed. You'll need a whole range of more data to answer that question, but if you want to have a first shot, you did it quite well Better use Kelvin instead of Celsius, it's much easier. Let's neglect the mixing effects between sweet and salt water, and the salt secretion when the whole ocean drops a 0.5K in temperature. Just an example (20*283+1x273)/(20+1)=282.5K The vertical temperature gradient of the Atlantic between 0 and 700 meters will resp. go from 283K to just above freezing point I guess. Let's say it's average 278K. To cool that volume of the Atlantic (A = 106,400,000km2 * 0.7km = 7.448×10⁷ km3) with a 0.5K would require like the example of above (A*278+B*273)/(A+B)=277.5K. Simplifying this formula results in 0.5A=4.5B. So, B is 9 times smaller than A. B=8.3×10⁶ km3. It looks like that's the whole Greenland ice sheet. Am I right? Thank you buildreps! The volume of the Greenland ice sheet as reported in the article is 2.61x10 6 km3. wattsupwiththat.com/2015/12/30/greenland-retained-99-7-of-its-ice-mass-in-20th-century/Let's say that the area of the N. Atlantic is 20x10 6 mi2 x 2590 km2/mi2 x 0.7 km = 36.26x10 9 km3 Substituting into your formula. A = 4.029x10 9 (or 4.029 billion km3). This would equal an area 1543 times the volume of the Greenland ice sheet? So ... the answer is ... there is nowhere near enough ice to cool the N. Atlantic by 0.5 C even if you melted all of it???
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Post by acidohm on Dec 31, 2015 8:59:15 GMT
Just occurred to me that I may have destroyed my number one answer for the increasing volumes of cold water moving down the Labrador Current and interfering with the NAD ... not to mention the temperature changes (-0.5 to -1.5 C) that are occurring, according to Argo at depths of 0-700 meters (and below with smaller temp changes) in the North Atlantic. These are occurring to very large quantities of water north of about 45 N latitude. [ [/span][/quote] TBH Missouriboy, I never thought about Greenland ice sheet melt when looking at the Lab current...my initial research shows it dispenses 1/3 of all fresh water from that goes into the arctic, via hudson bay...
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Post by acidohm on Dec 31, 2015 9:03:53 GMT
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Post by sigurdur on Dec 31, 2015 13:39:35 GMT
Just occurred to me that I may have destroyed my number one answer for the increasing volumes of cold water moving down the Labrador Current and interfering with the NAD ... not to mention the temperature changes (-0.5 to -1.5 C) that are occurring, according to Argo at depths of 0-700 meters (and below with smaller temp changes) in the North Atlantic. These are occurring to very large quantities of water north of about 45 N latitude. So, if ice melt is not contributing a large portion of this cooling, then what the hell is? Is loss of heat to atmospheric warming so dramatic, that with little warm recharge, that alone (largely) could account for all this water cooling in the N. Atlantic at depth? I have not calculated the volumes of water we are talking about, but they are very large. Increasing salinity in the northeastward moving expansion eddy of cooling water keeps the leading edges subducting back to the southeast (and perhaps the northwest as well?). We have seen this in previous Argo sections. Winds and the Coriolis effect keep the sub-polar gyre operating but the amount of warm water appears to be dwindling. Is it now feeding largely on itself??? and becoming colder and colder??? Shooting from the hip here. We do know however that in select years after 2007, large quantities of cold water have crossed the subtropical gyre and cooled the Sargasso Sea. Missouriboy: Your idea of where the cold water is coming from potentially came from Dr. Mann, as that is what he and a few others claim. I only know that there are a lot of things we don't know about how the ocean operates, so am wide open for any idea.
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