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Merged Global Warming Discussion II: Heated Conversation

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aleCcowaN said:
Why on Earth the ocean level dropped 8 mm from September 2012 to September 2013 while the atmosphere wasn't retaining much more water (even probably less), it didn't snow a lot more, glaciers and ice sheets continued to melt, and the oceans become warmer during the exact same period?
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I would bet on an equivalent increase in arctic sea ice, just because I'm rich so I like to waste your time and my money.
 
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Froggy Papy said:
I would bet on an equivalent increase in arctic sea ice, ...
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Arctic sea ice minimum in 2013 is 6th-lowest on record
After an unusually cold summer in the northernmost latitudes, Arctic sea ice appears to have reached its annual minimum summer extent for 2013 on Sept. 13, the NASA-supported National Snow and Ice Data Center (NSIDC) at the University of Colorado in Boulder has reported. Analysis of satellite data by NSIDC and NASA showed that the sea ice extent shrunk to 1.97 million square miles (5.10 million square kilometers).

This year's sea ice extent is substantially higher than last year's record low minimum. On Sept.16, 2012, Arctic sea ice reached its smallest extent ever recorded by satellites at 1.32 million square miles (3.41 million square kilometers).
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No one should bet on a known fact.

ETA: This probably has little relation to warmer oceans. The exceptionally low Arctic sea ice extent in 2012 is attributed at least partially to the collapse of an ice dam allowing warm river water to mix with the sea ice.
Effects of Mackenzie River discharge and bathymetry on sea ice in the Beaufort Sea
 
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One clue more:

If you take a look again to this post, you need to also look for one source like this article in Nature adding important elements to understand the story. Mainly the figure with isopycnals may turn the light bulb on and lead you to the answer (the answer is not that, but it's named above in the page)

I lost a link to a tabular version of every sea water property -some 500 pages-. Once I've found it, I'll link it.
 
Tropical Pacific Ocean remains on track for El Niño in 2014
http://www.bom.gov.au/climate/enso/
Sea surface temperature (SST) anomalies in the tropical Pacific Ocean have increased steadily since February, and are now greater than +0.5 °C in the key NINO regions. However, above-average SSTs also extend into the western tropical Pacific, meaning strong west to east gradients in tropical Pacific SST anomalies are yet to become established. As a result, atmospheric indicators—such as the Southern Oscillation Index and trade winds—have only shown a weak response.
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As we know, it's all about the gradients. All that warm surface must be kicking out some extra heat, though. Even if there is no El Nino and the warm water washes back West, 2014 and 2015 will be warm years for surface temperatures. The mythical Pause is dead; long live the mythical Surge.
 
aleCcowaN said:
One clue more:

If you take a look again to this post, you need to also look for one source like this article in Nature adding important elements to understand the story. Mainly the figure with isopycnals may turn the light bulb on and lead you to the answer (the answer is not that, but it's named above in the page)

I lost a link to a tabular version of every sea water property -some 500 pages-. Once I've found it, I'll link it.
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Does the ocean mean temperature of 3.5 degrees C have anything to do with this? And perhaps the volume of water that is close to that temperature? If you heat up a lot of water that is below 4 degrees C the density would increase and thus the volume would decrease.

ETA: on another note, I'm not sure I want to actively want to play this game any longer since I feel way out of my depth, but I am fascinated by what I'm reading even when it's in a very cryptic form from a fellow ESL speaker
 
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Turgor said:
Does the ocean mean temperature of 3.5 degrees C have anything to do with this? And perhaps the volume of water that is close to that temperature? If you heat up a lot of water that is below 4 degrees C the density would increase and thus the volume would decrease.

ETA: on another note, I'm not sure I want to actively want to play this game any longer since I feel way out of my depth, but I am fascinated by what I'm reading even when it's in a very cryptic form from a fellow ESL speaker
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You are really good at this ! (and good sport!) It has ALL to do!

But I'll give you a hint. What you said about 4°C or less is only true for distilled water. Salty water is always denser as it cools. What is the same to say this platitude -a much needed platitude- : sea water has a thermal expansion coefficient.

That coefficient varies with temperature -obvious-, with salinity -expectable- and with pressure. Sea water at 2000 dbars that warms from 3 to 4°C will dilate much less than what it would contract sea water at 400 dbars that cools from 10 to 9°C. The heat content remains constant, yet the sea level has dropped. Is this minimal? No. If I could move the temperature gradient one degree centigrade in some 1000-m layer and move it in the opposite direction in a certain different 1000-m layer, I would rise the sea level one whole metre, more or less, without adding a single Joule of energy.

In the original question there's a link to the ocean heat content repository. Values for 0-700m and 0-2000m are given. A value for 700-2000 could be gotten by subtraction (it's wrong, it's a dirty method, but good enough for this kind of analysis). The question is, can the oceans go warmer and the sea level drop at the same time? Yes, it happens about 15% of the time.

How much exactly? Well, we have to keep thinking, but the answers are just around the corner.
 
Reality Check said:
The exceptionally low Arctic sea ice extent in 2012 is attributed at least partially to the collapse of an ice dam allowing warm river water to mix with the sea ice.
Effects of Mackenzie River discharge and bathymetry on sea ice in the Beaufort Sea
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Interesting! Thanks, I only read the intro due to the pay wall.

The Makenzie River basin is about the same size as Germany, France, Spain and Poland combined at approx 1.8 million sq. kilometers.

One can imagine the significance of the increased albedo of that huge area as Northern Canada warms and there are less days with snow cover, exposing the darker ground and water, which then absorbs more heat. All that increased heat will get dumped into the Arctic. Now consider the effects of all the rivers that flow into the Arctic getting warmer.

The region is getting warmer and the impacts are huge.

Pine bark beetles have devastated large area of pine forests and are spreading further into the Makenzie River Delta. Lumber mills in BC are closing and people are losing their jobs due to the loss of pine trees. The beetles are likely to spread all the way across North America. They have already destroyed pine trees from Utah to Colorado up into northern BC and across into Alberta.
http://http://www.cbc.ca/news/canada/british-columbia/pine-beetle-blamed-as-quesnel-houston-sawmills-to-close-1.2224677

A map of the pine tree loss on the right

http://www.canadiangeographic.ca/wildlife-nature/?path=english/species/mountain-pine-beetle


Moose are now dying off across North America as well. One theory is that the winters are no longer cold enough to kill off the ticks that attack them, just like the pine beetle larvae.

http://www.nytimes.com/2013/10/15/science/earth/something-is-killing-off-the-moose.html

Hopefully they won't go extinct. Love the size of this one!

 
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aleCcowaN said:
You are really good at this ! (and good sport!) It has ALL to do!

But I'll give you a hint. What you said about 4°C or less is only true for distilled water. Salty water is always denser as it cools. What is the same to say this platitude -a much needed platitude- : sea water has a thermal expansion coefficient.

That coefficient varies with temperature -obvious-, with salinity -expectable- and with pressure. Sea water at 2000 dbars that warms from 3 to 4°C will dilate much less than what it would contract sea water at 400 dbars that cools from 10 to 9°C. The heat content remains constant, yet the sea level has dropped. Is this minimal? No. If I could move the temperature gradient one degree centigrade in some 1000-m layer and move it in the opposite direction in a certain different 1000-m layer, I would rise the sea level one whole metre, more or less, without adding a single Joule of energy.

In the original question there's a link to the ocean heat content repository. Values for 0-700m and 0-2000m are given. A value for 700-2000 could be gotten by subtraction (it's wrong, it's a dirty method, but good enough for this kind of analysis). The question is, can the oceans go warmer and the sea level drop at the same time? Yes, it happens about 15% of the time.

How much exactly? Well, we have to keep thinking, but the answers are just around the corner.
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Interesting. I have wondered how much we understand the changes that just look like 'noise' to me.

You said this happened at the wrong time, but I did find it intersting see that floods in Australia do lower the sea level.

Scientists have worked out that a combination of weather patterns over the Indian and Pacific oceans funnelled so much rain over Australia that the world’s sea levels fell in 2011.
Unlike other continents, the soils and topography of Australia prevent almost all of its rain from running off into the ocean, causing dry areas of Australia to act like an enormous sponge
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http://econews.com.au/news-to-sustain-our-world/study-aust-floods-lowered-global-sea-levels/

Which really makes me wonder about scientists like Judith Curry

http://judithcurry.com/2014/04/24/slowing-sea-level-rise/
Can someone then tell me how you can infer that sea level rise is accelerating due to AGW, when compared with sea level rise for the first half of the 20th century?
It is clear that natural variability has dominated sea level rise during the 20th century, with changes in ocean heat content and changes in precipitation patterns.
Once again, the emerging best explanations for the ‘pause’ in global surface temperatures and the slow down in sea level rise bring into question the explanations for the rise in both in the last quarter of the 20th century. And makes the 21st century of sea level rise projections seem like unjustified arm waving.
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Is she suffering from early onset dementia?
 
a_unique_person said:
Interesting. I have wondered how much we understand the changes that just look like 'noise' to me.

You said this happened at the wrong time, but I did find it intersting see that floods in Australia do lower the sea level.



http://econews.com.au/news-to-sustain-our-world/study-aust-floods-lowered-global-sea-levels/

Which really makes me wonder about scientists like Judith Curry




Is she suffering from early onset dementia?
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About this Curry person, I'd prefer to avoid any analysis of her words. But you are naming the period of floods in Australia -like macdoc did earlier- and that is very interesting.

I've not done this analysis previously, so, here I go, without safety net. From sealevel.colorado.edu we can take the value for April 2nd 2010 -51.199mm- and the value for April 4th 2011 -45.248mm- a drop of 5.95 mm in one year. Let's add 1.25 mm of melted ice, it's a 7.2mm drop.

Let's examine the ocean heat content from NOAA-NODC. For the first quarter of 2010, the global ocean heat content "anomaly" was 11.198 x 10E22 J in the layer 0-700m, and 15.881 for the layer 0-2000m, so, a dirty and wrong value by some, 3 or 5%? for the layer 700-2000m could be 4.7 x 10E22 J.

Now the same for 2011: 10.729, 15.216 and 4.5.

So the heat content in the 0-700m layer dropped, in the 700-2000m layer kept constant, then, much roughly, the ocean didn't dilate. Then, the 7mm drop comes from elsewhere, for instance, Australian floods (Did somebody think that I would consider Fasullo to be wrong?)

Back to my question, same data offered for September 2012 and 2013.

2012: 10.642, 15.346, 4.7
2013: 11.165, 16.297, 5.1

Woah! Almost the same. Or worse, It should have risen. Was all of it wrong!!?? What do you think?

The question is: each layer is from one metre to a few hundred metres thick, but it covers the whole world ocean. These comparisons can't be done that way.

Let's try a smaller area, the southern Atlantic (the same size as Asia)

2012: 1.68, 3.059, 1.4
2013: 1.462, 2.632, 1.2

sea level most probably dropped much (its contribution, I mean).

Let's try northern Atlantic

2012: 2.339, 3.246; 0.9
2013: 2.979, 4.232; 1.3

contributed to its rise.

This analysis gives us Southern Atlantic and Pacific contributing to a sea level drop, an Indian Ocean neutral, and Northern Atlantic and Pacific -the smaller- contributing to a rise. Not convincing? Of course it isn't.

That's why you have access to software and data -hundreds of megabytes in zipped file- from ARGO. I've been running this analysis since 2009 and it's amazing how subtle differences of 0.2°C here and there contribute to masses of heat being kept or lost by the oceans and sea level rising or dropping several millimetres.

But this is dizzying, and surely I've lost you.

I promise, when I found the 3D "table" of density as a function of temperature, salinity and pressure, I will show you with a simple problem of two thin layers how we can easily cool the seas and get the sea levels rising, and the opposite.
 
a_unique_person said:
My understanding is that melting sea ice does raise the sea levels, but not to a significant extent compared to the other causes of sea level rise.
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If you have a glass of water with ice cubes and the cubes melt -without the liquid modifying its temperature-, does the water level in the glass rise, drop or stay constant? Remember that the ice is not part of the liquid level, and that by sea ice we only include floes -ice cubes in the glass-, not chunks of ice-shelves -new ice cubes dropped in the glass-.
 
Reality Check said:
But a small rise in sea water. Sea ice is lower in salt than sea water.
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Because the salt that was in the water is now in the ocean. The salt doesn't just vanish.
Reality Check said:
When it melts the sea loses salinity, loses density and gains volume.
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Wrong. This is why blogs should not be used as sources. That is just plain wrong.

The salt free ice was originally made from salt water. So the amount of salt in the water when it melts is the same. It's not like the ice came from some other planet.

Even the ice from glaciers and water from melting snow was originally from the oceans. There is no loss of salinity when it returns.

Because the salt left behind when ice forms balances when the ice melts.

I can't believe how stupid some blogs can be.
 
r-j said:
Wrong. This is why blogs should not be used as sources. That is just plain wrong.
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Wrong. This is why ignoring what blogs contain is wrong. That is just plain wrong, r-j :jaw-dropp.
Sea level rise due to floating ice?
...demonstration the water level rises when ice melts in sea water...
Doesn’t that contradict Archimedes’ principle?

According to Noerdlinger and Brower (2007) it doesn’t because the principle refers to weight and not volume. The salt in sea water raises its density from about 1000 kg/m3 for salt free water to 1026 kg/m3 for normal sea water. The ice however is nearly salt free because of a process called “brine rejection” (the salt from sea water doesn’t enter the crystal structure of ice).

When the ice melts then this is a kind of freshening of the ocean and the overall salinity is lowered. The lower salinity, the lower density and the larger volume.

The melting of sea ice therefore doesn’t increase the mass but it increases the volume and therefore causes the water level to rise. After Noerdlinger’s and Brower’s calculations the volume of the meltwater is about 2.6% larger than the displaced sea water.
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it is simple to understand, r-j.
The amount of salt in the sea water when the ice melts is the same.
The volume of sea water has increased by the volume of the melted ice.
Thus the salinity (salt per volume) of the sea water has decreased.
The lower the salinity, the lower the density of the sea water.
The lower the density of the sea water, the more volume it has.
 
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Melting of floating ice and sea level rise
Contrary to popular belief, the melting of floating ice (in the form of ice shelves, icebergs and sea ice) may have a non-zero impact on sea level. This is because the melting process cools and dilutes the oceans on average, and unless these opposing effects exactly balance each other there will be a net change in the ocean density. We discuss how these subtle effects can be quantified and put bounds on the potential sea level rise associated with melting of the ice masses that are currently afloat in the world's oceans.
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The melting of floating ice raises the ocean level
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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