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Old 29-04-2018, 13:30   #751
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Re: Northwest Passage - 2018

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The weight of the snow would cause the ice to sink a bit more (Archimedes' principle).

As well the snow is a really good insulator, thereby trapping more heat in the water.
Now here's something that puzzles me. With no ice blanket, will a "warm" ocean loose heat to the colder atmosphere slower than it will heat from albedo? Having stood in frozen northern climes in the winter, and observed how feeble the sun is, and with a basic understanding of light polarisation and refraction - I just cannot see how this would be that big a positive feedback. Especially considering increased cloud cover that I would expect would also occur.
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Old 29-04-2018, 14:11   #752
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Re: Northwest Passage - 2018

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Originally Posted by SailOar View Post
VOTE TOTALS
Sea Level Rise: 1
Sea Level Same: 3
Sea Level Fall: 0

Currently voter turnout is light, and there is no waiting in line to vote. Shall we keep the polls open for a few more hours to allow everyone to express their preference? We can call this "science by ballot".
I do believe you have all the votes you are likely to get ..
Now is the time to depart your wisdom and give the answer.
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Old 29-04-2018, 15:10   #753
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Re: Northwest Passage - 2018

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Originally Posted by Reefmagnet View Post
Now here's something that puzzles me. With no ice blanket, will a "warm" ocean loose heat to the colder atmosphere slower than it will heat from albedo? Having stood in frozen northern climes in the winter, and observed how feeble the sun is, and with a basic understanding of light polarisation and refraction - I just cannot see how this would be that big a positive feedback. Especially considering increased cloud cover that I would expect would also occur.
Remember that Arctic is warming twice as fast as the rest of the planet.

Here is the long term forecast:



The air temeparture in summer will be higher than the water temepature

Quote:
The warmest sea in Pangnirtung in August is 8°C/46°F, and the coldest sea temperature in August is 0°C/32°F. Average water temperature in Pangnirtung in August is 4°C/39°F.
The average high and low temperatures at Pangnirtung for August are 11° and 6°. The air is still warmer that the water. The net heat transfer will be from air to water.
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Old 29-04-2018, 16:46   #754
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Re: Northwest Passage - 2018

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Originally Posted by jackdale View Post

...

The air temeparture in summer will be higher than the water temepature



The average high and low temperatures at Pangnirtung for August are 11° and 6°. The air is still warmer that the water. The net heat transfer will be from air to water.
Early to mid season yes, but later in the season I would expect air temperature to drop whilst the sea remains warm due to thermal inertia. This would occur before any appreciable ice reformed as I'm pretty sure ocean temperature would need to be near freezing at least? I also think sea surface temperatures don't necessarily reflect the average temperature of the water.
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Old 29-04-2018, 17:24   #755
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Re: Northwest Passage - 2018

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As a thought experiment, if all the Arctic sea ice were to melt (and nothing else changed), would the sea level rise, stay the same, or fall?
Sea Level Rise: 1
Sea Level Same: 3
Sea Level Fall: 0

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I do believe you have all the votes you are likely to get ..
Now is the time to depart your wisdom and give the answer.
I suspect my wife would agree with you that whatever wisdom I may have had has departed me.

As to the question at hand, I am torn between two lines of thought. Since I subscribe to the idea of a democracy, my inclination is to accept the wisdom of the majority and conclude that the melting sea ice will not change the sea level.

But I also have respect for the problem-solving abilities of scientists, and this study says that sea level will rise as a result of melting sea ice (Arctic and Antarctic included). So I guess everyone has to decide for themselves who to believe.
Quote:
Summary
It is shown that the melting of ice floating on the ocean will introduce a volume of water about 2.6 per cent greater than that of the originally displaced sea water. The melting of floating ice in a global warming will cause the ocean to rise. If all the extant sea ice and floating shelf ice melted, the global sea level would rise about 4 cm. The sliding of grounded ice into the sea, however, produces a mean water level rise in two parts; some of the rise is delayed. The first part, while the ice floats, is equal to the volume of displaced sea water. The second part, equal to 2.6 per cent of the first, is contributed as it melts. These effects result from the difference in volume of equal weights of fresh and salt water. This component of sea rise is apparently unrecognized in the literature to date, although it can be interpreted as a form of halosteric sea level change by regarding the displaced salt water and the meltwater (even before melting) as a unit. Although salinity changes are known to affect sea level, all existing analyses omit our calculated volume change. We present a protocol that can be used to calculate global sea level rise on the basis of the addition of meltwater from grounded and floating ice; of course thermosteric volume change must be added.
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Old 29-04-2018, 17:30   #756
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Re: Northwest Passage - 2018

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Remember that Arctic is warming twice as fast as the rest of the planet.

The air temeparture in summer will be higher than the water temepature

The average high and low temperatures at Pangnirtung for August are 11° and 6°. The air is still warmer that the water. The net heat transfer will be from air to water.
Heat loss can also occur through radiative cooling.
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Old 29-04-2018, 18:17   #757
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Re: Northwest Passage - 2018

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Originally Posted by SailOar View Post
Heat loss can also occur through radiative cooling.
Heat loss can occur through four different processes: convection, conduction, advection and radiation.

https://sciencing.com/difference-con...s-8479535.html

Regardless, Arctic water in summer is cooler than Arctic air.
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Old 29-04-2018, 18:27   #758
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Re: Northwest Passage - 2018

Quote:
Originally Posted by jackdale View Post
Heat loss can occur through four different processes: convection, conduction, advection and radiation.

https://sciencing.com/difference-con...s-8479535.html

Regardless, Arctic water in summer is cooler than Arctic air.
...And also via evaporation. I think this would be a big contributor to the cooling of an exposed ocean regardless of the ambient air temps. In fact the warmer the air, the greater the cooling effect on the sea.
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Old 29-04-2018, 19:17   #759
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Re: Northwest Passage - 2018

Quote:
Originally Posted by SailOar View Post
Sea Level Rise: 1
Sea Level Same: 3
Sea Level Fall: 0


I suspect my wife would agree with you that whatever wisdom I may have had has departed me.

As to the question at hand, I am torn between two lines of thought. Since I subscribe to the idea of a democracy, my inclination is to accept the wisdom of the majority and conclude that the melting sea ice will not change the sea level.

But I also have respect for the problem-solving abilities of scientists, and this study says that sea level will rise as a result of melting sea ice (Arctic and Antarctic included). So I guess everyone has to decide for themselves who to believe.
sorry autocorrect. Was supposed to be impart. Not depart.
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Old 30-04-2018, 04:24   #760
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Re: Northwest Passage - 2018

The Great Totten Glacier is Floating on More Warming Water Than We Thought | Robert Scribbler

A massive glacier the size of France is floating on more of a warming ocean than previously thought. The Totten was once considered to be stable. However, over recent years, concerns were raised first when plumes of warm water were identified approaching the glacier’s base and later when it was confirmed that Totten was melting from below. Concerns that were heightened by new research identifying how winds associated with climate change were driving warmer waters closer and closer to the huge ice slab.

After follow-on expeditions to Totten, scientists (over the past two years) discovered that the glacier’s floating underside was losing about 10 meters of thickness annually even as its seaward motion was speeding up. Now, new research has found that more of the Totten Glacier is floating upon this warming flood of ocean water than previously thought.

Beneath Totten lies a large ridge upon which most of the glacier is grounded as it flows toward the sea. But penetrating this ridge are numerous gateways that, if melted through, provide sea water access to the glacier’s interior. And recent studies have found that a number of these gateways have been thawed open, allowing warming ocean waters access to sections of the glacier that are hundreds of miles inland.


A massive glacier the size of France is floating on more of a warming ocean than previously thought.
Taking into account past reports of thinning along the glacier’s underside,
and this is a rather concerning finding. Image source: Australian Antarctic Division.



Warm water invasion pathways have opened along Totten’s previous grounding line.
These openings have allowed water to flood far inland beneath the glacier. The result is a less stable, more rapidly moving ice sheet.
Image source: Jamin Greenbaum/University of Texas-Austin.
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Old 30-04-2018, 04:48   #761
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Re: Northwest Passage - 2018

SailOar - I hope you're satisfied. I'm leaving in a couple of days for a 400nm coastal run from Charleston to the Chesapeake, and thanks to you I am going to have to completely recalculate my navigation due to anticipated MMGW-induced fluctuations in the set of the gulf stream current.
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Old 30-04-2018, 08:22   #762
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Re: Northwest Passage - 2018

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SailOar - I hope you're satisfied. I'm leaving in a couple of days for a 400nm coastal run from Charleston to the Chesapeake, and thanks to you I am going to have to completely recalculate my navigation due to anticipated MMGW-induced fluctuations in the set of the gulf stream current.
Sounds like fun! Hope you have a great time. Navigation is fun -- it keeps one's mind nimble.

I'm just finishing reading a small, out-of-print book called North to Baffin Land, by John Rowland. In 1911, just after graduating from Yale (he had to wait until he returned from his voyage to find out whether he had passed his exams (he passed)), he delivered a 30' motor-sailor yawl for medical mission work to Baffin Land (for quite a while it was thought that Baffin Island was part of mainland Canada, and therefore called Baffin Land). Even as recent as 1911, charts were poor in southern Labrador, and terrible in Hudson's Strait and points north. Fog was frequent, tides were 20-30', compass was useless, sextant only worked if you had a clear sky and a clear horizon -- though he figured out a way to make an artificial horizon with a bowl of fuel oil??? Rowland's adventures make my life seem extraordinarily tame by comparison!
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Old 30-04-2018, 16:21   #763
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Re: Northwest Passage - 2018

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Solar cycle 23 began in 1996. Here is a plot of temperatures against sunspot activity. Temperatures are increasing, sunspot activity is decreasing.

Newhaul could be on the money. And we only need a handful of months to see if this is the case...

ICE AGE: Forecaster predicts 'coldest winter on record'



Quote:
MINI Ice Ages, horrific thunderstorm and cyclone seasons, and a lot more floods - the future of Australia's weather looks grim according to amateur weather forecaster David Taylor.
Mr Taylor - who runs East Coast Weather Facebook page - has correctly predicted major weather events in the past, and his latest terrifying prediction was that Australia could experience its coldest winter on record.
Temperatures and snowfall could reach shocking levels compared to previous years, and icy conditions could impact huge areas of the country in periods.
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Mr Taylor previously told the Cairns Post while it will be "slightly cooler than normal in the north...the real cold will be in the southern states (NSW) and south-east Queensland".
He uses sunspots and interprets them with models to get readings of upcoming weather events, but the majority of weather sources, including The Bureau of Meteorology, don't use this method.
According to National Weather Service: "Sunspots are areas where the magnetic field is about 2500 times stronger than Earth's, much higher than anywhere else on the sun."
"Because of the strong magnetic field, the magnetic pressure increases while the surrounding atmospheric pressure decreases.
"This in turn lowers the temperature relative to its surroundings because the concentrated magnetic field inhibits the flow of hot, new gas from the Sun's interior to the surface."
Mr Taylor wrote a "winter update" on East Coast Weather on April 16.
According to the forecaster, sunspots play a huge role in the earth's weather, including events such as El Nino and volcano activity.
"Sunspot activity is normally 40,000 to 50,000 but at the moment it's down to just 50," Mr Taylor said.
He said the drop in sunspot activity normally affects winters but does not particularly mean summers will be any cooler.
"When sunspot activity drops it normally affects the winters long before any impact on our summers.
"The sunspot activity has reached an all-time low and should be like this for the next seven to 15 years.
"The last time the planet has experienced anything like this was back in 1645 and it created a mini Ice Age.

"I am not saying that it will create a mini Ice Age, but I am saying that this winter overall should be cooler than what we (are) normally used to and we could see snow in areas that hasn't seen snow in a very long time or even snow in places where it hasn't snowed before."
Mr Taylor said this has already been evidence in the Northern Hemisphere where it was one of the coldest winters on record for Russia, and Europe recorded snow in places where snow hadn't been previously recorded.
He said this was due to "big winter storms" formed by "really powerful and deep low pressure systems", and the Southern Hemisphere should experience at least one of these systems.
This means very cold conditions for Australia and possible snow fall to places where it hasn't snowed before.
Coming out of winter he said Australia could see "a horrific thunderstorm and cyclone season" due to the "interaction of colder than normal cold front and possibly hotter than normal summer temperatures".
Future summers could possibly hold "a lot more floods".
"Winter overall should be cooler than normal but if one of these winter storms affects the Australian mainland, then this winter will definitely be one of the coldest that we have experienced in a long time - possibly even on record," Mr Taylor said.
"Winter after this season should gradually get cooler each year until sunspot activity starts to increase."
The Bureau of Meteorology has not yet released their 2018 Winter Seasonal Outlook.

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Old 30-04-2018, 17:13   #764
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Re: Northwest Passage - 2018

Check the meandering of the jet streams.... some areas will be colder, some warmer. Apparently the speed of the jet streams and hence any meandering is related to the temperature difference between the equator and the poles. As that difference decreases, meandering increases.
https://phys.org/news/2015-02-eviden...et-stream.html
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Old 01-05-2018, 04:42   #765
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Re: Northwest Passage - 2018

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Sounds like fun! Hope you have a great time. Navigation is fun -- it keeps one's mind nimble.

Nimble indeed! I'm learning about the so-named 'Charleston-Bump' where the gulf stream takes a pronounced jog to the east off of Charleston. There is some counter-current inshore of the stream so it's always fun trying to figure out the most efficient way to catch the stream and take advantage of its push towards Hatteras. There's a huge swath of high pressure & light winds settling in so any favorable current would be nice. I've fortunately only ever sailed around the notorious Cape Hatteras in reasonable conditions but it's always a bit spooky nonetheless.

I'm just finishing reading a small, out-of-print book called North to Baffin Land, by John Rowland. In 1911, just after graduating from Yale (he had to wait until he returned from his voyage to find out whether he had passed his exams (he passed)), he delivered a 30' motor-sailor yawl for medical mission work to Baffin Land (for quite a while it was thought that Baffin Island was part of mainland Canada, and therefore called Baffin Land). Even as recent as 1911, charts were poor in southern Labrador, and terrible in Hudson's Strait and points north. Fog was frequent, tides were 20-30', compass was useless, sextant only worked if you had a clear sky and a clear horizon -- though he figured out a way to make an artificial horizon with a bowl of fuel oil??? Rowland's adventures make my life seem extraordinarily tame by comparison!
No kidding! Amazing what these mariners accomplished, and that was early 20th century. Imagine what it was like before they figured out how to calculate longitude. But of course Colombus was headed for the East Indies was he not? I'll never forget the chapter in Two years Before The Mast where, on their return trip from California around S. America, the captain waits out safe passage through an opening in the ice at the entrance to the Straights of Magellan. The crew has no idea why they're waiting there so long in winter, and since it was the 1840's the captain must have been making his decision on pure instinct.
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