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Messages - SATire

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Arctic sea ice / Re: Arctic sea ice free (extent)
« on: April 10, 2013, 10:08:11 PM »
Dear colleagues,

I would like to ask you to calm down a bit. The topic is interesting, the changes are steep - but please get cool a bit. The worst thing here is to get called "Alarmist" without reason - so reason ist important. Errors are often made, like big ones by myself - but agree, when you missed something important or calculated in stupid way. That is normal and nothing bad - bad is only, if you are the only one not able to see, when you are wrong...

Something in the discussion above is misleading by exaggeration and/or misunderstanding - that could be ruled out easily. E.g. End of July is not 1. July. Ice free July is not ice free after July. Next year July is not end of this years June, a picture of ice condition in Sept. 2012 does not indicate albedo of this years May...

I think the strength of this site is the interdisciplinarity - experts discuss with noobs and both learn and are surprised again and again by daily novel pictures. Please take the comments serious in any case - there is no truth anymore but todays observations. Risks should be rated, but not hyped because that is dangerous for credibility.

I am sorry if I disturbed again. I just love to read all the comments here because of their style without bickering. 

Since I believe in the exponential decribing the volume due to albedo-feedback, I would guess 2 Mio km2 (of about 1m thick ice) as most probable value. Since the standard deviation is quite large (also about 2 Mio km2) I voted for the largest bin closest to that value: 0-1 Mio km2.

Arctic sea ice / Re: Year-round ice-free Arctic
« on: April 03, 2013, 05:30:08 PM »
Your calculation is wrong by a factor of 286.  To increase salinity from 34 PSU to 35 PSU, you need to lower the volume by a factor of 1/35, i.e. evaporate away 2.86 metres from the top 100 metres.
Peter Ellis, you are right with that. What a shame - this thread is bs.

The halocline is not only due to sea ice formation, but also due to large amounts of freshwater influx from rivers draining into the comparatively closed Arctic basin. 
There are no rivers in Svalbard or Barents - the various processes for halocline formation are described nicely in that linked paper.

In any event, evaporation is low at Arctic temperatures.  I'm not quite clear what you're aiming at by comparing it to the heat taken to warm the water up by a few degrees.  If you start with water around freezing point and warm it up a few degrees, you get slightly warmer water, not great clouds of water vapour.
Are you sure with that? Cold air from continents getting warmed over the ocean are very dry and can take significant water from evaporation. E.g. look at the "smoke" next to leads in the ice. But there is of course not enough heat for vaporization of 2.86 m water column - so I would agree to close this thread and delete it, at least until I have lost the red color from my face  :-[

Arctic sea ice / Year-round ice-free Arctic
« on: April 03, 2013, 01:53:11 PM »
After reading other threads in this forum and Neven's blogs I assume some agreement about the prediction of an ice-free arctic in summer between this year and 2017 (e.g. caused by exponential decline of ice volume due to albedo-feedback, I also assume some agreement from climate paleontology, that current atmospheric CO2 content of 400 ppm is similar to the Pliocene or even Miocene situation. Therefore, we are now in a transition period from (inter-)glacial clima to a glacial free clima at least in northern hemisphere. What is unclear and of interest are the major processes driving this transition and their time scale. I would like to describe a possible process for the transition to a year-round ice-free arctic basin below.

If you read this, please be aware, that I am not a climate specialist nor a ocean scientist. I am only an interested amateur in this field (instead I am an engineer with a PhD in physics, for the case you want to know that). But since the professionals are failing so badly predicting current situation in the arctis for 2050 using history-proofed complex models, we all have a chance to do better even with simple empirical pictures. So I am interested in your critics and thoughts, maybe we can find a proper description of probable transition schemes together.

As introduction I would like to point to an article describing the waters and the halocline in the arctic ocean very nicely und readable:
In figure 1 in that paper you find salinity- and temperature profiles in the Eurasian basins (Nansen basin (yellow) and Amundsen basin (green)), the Makarov basin in the center of the arctis (violet) and the Canada basin next to Alaska (blue). Some possible origins of the haloclines there are described quite understandable.

In the Eurasian basin below a depth of ~100m warm waters of atlantic origin are hold back by the halocline. Since the halocline is a result of sea-ice e.g. north of Svalbard and in Barents sea, an ice-free arctic can result in a slow "atlantification" of the arctis. An absence of a halocline in the Eurasian basin would result in a mixing with deeper warm waters preventing the formation of ice in winter.

An additional mechanism able to destroy the halocline could be vaporization of water over an ice-free Eurasian basin in autumn: Since the salinity is only 1 PSU lower in the top 100 m (yellow curve for Nansen basin) and 1 PSU is 0.1% salt content, only 10 cm of water need to be vaporized to result in disappearing halocline there (0.1% x 100 m = 0.1 m) after some mixing. The heat needed to vaporize this water has to be stored in the upper water layer, e.g. the top 10 m. Since 2700 kJ/kg are needed (2256 kJ/kg vaporization enthalpy + 420 kJ/kg for 0->100 °C), for comparison that is the energy needed to melt 0.8 m ice (334 kJ/kg) or to heat a 10 m water culumn by 6.4 °C. I think that amount of heating is well in reach for an ice-free ocean in the summer.

In the Amundsen Basin this numbers would be 0.15 m to vaporize (0.15% x 100m, heat equal to 10 m water heated by 10 °C), in Makarov basin 0.3m (2 PSU x 150 m) and in the Canada basin 1 m (8 PSU x 50 m plus 3 PSU x 200 m). Therefore, I estimate the transition time to an all-year ice-free ocean 1-2 years for the Eurasian basin and 1-2 decades for the Canada basin. Both transitions would start after the ice melted early enough to result in a surface temperature of 5-8 °C  (7-10 °C above melting temperature there).

To conclude, I have drawn a picture to describe how and when evaporation could result in a perennial ice-free state above the deep basins in the arcits and I am asking for your thoughts. This is not a proper prediction for the bays (e.g. Hudson) and the shelf waters (Siberian seas, Kara, Tschuktschen, Makenzie delta,...) - I think some ice will be grown in that areas under the influence of fresh-water inflow and cold air from continents.

Since open sea in the arctis will kill the polar vortex, the jet stream and the atmospheric flux of energy to the arctis the oceans currents must cool the equator on the long run. Evaporation will suck the Atlantic water north and cover the continents with a ton of wet snow. The persistent depression over the artic ocean will kill the jet stream and the westerlies - leaving only the Antarctis to cool the Equator by air. What would that mean for monsuns, westerly, northern trade wind, ... persistent winter weirdness globaly, I guess. 
And what would that mean to Greendlands ice -  that last memory of the glacial periode? Probably some more water to motivate our dykers.
Erratum: Since the change of salinity by vaporization is calculated wrong in this message (see comment from Peter Ellis below), vaporization is not reasonable to destroy the halocline. Instead other processes could be discussed in this thread. I am sorry for that mistake.

Arctic sea ice / Re: Length of melting season
« on: April 01, 2013, 05:48:30 PM »
one positive feedback: The more ice is molten, the more far north the remaining ice is retired. Far in the north in begins earlier to refreece when the sun is about to set. That is a positive feed-back, but not really positive enough to save the ice... 

Arctic sea ice / Re: Records and oddities
« on: March 10, 2013, 06:48:16 PM »
A4R - it seams like cracking has reached "mission accomplished"-state as there is no save haven left for multi-year-ice. Every part of multi-year-ice left has now a good chance to leave either via Fram-Express or to visit the sunny coast of Alaska for a short summer holiday to get extinct.

I am not sure, if the 2 oberservations discussed above "ice-volume transport through Fram stays constant" and "volume-melt has reached constant/maximum value" are linked - but I think so. Both are signs for record years to come until arctis is seasonaly ice-free, since after that date both values must decrease anyway. If the multi-years ice is gone, the only thing to export or to melt is then the ice grown in the winter just before. Therefore - to observe the 2 plateaus now is a sign that we will reach ice-free arctis soon, e.g. this year or in 5 years.

Arctic sea ice / Re: Records and oddities
« on: March 05, 2013, 08:32:32 PM »
When I look at at the ice speed forecasts and the fracturing, I am drawn to the fracturing that is occurring over the pole. Does this suggest the Fram is set to pump a lot of ice into the Atlantic?

Indeed - if transport of ice-volume through Fram is going to keep constant while ice thickness in the arctic ocean is decreasing, it would have to go faster. Obviously it is trying to keep that flow rate constant, thus increasing velocity and tearing the thick ice appart by doing so. The fractured ice is surely more mobile allowing to keep that flow rate constant, but why? And it can not be like this for ever, because the old thick ice will be gone soon...

Policy and solutions / Re: Will Renewable Energy "Solve Global Warming"?
« on: February 22, 2013, 02:27:29 PM »

I did understand quite well, that the projection is not the goal, since there is obviously no goal at all! But China and everybody else would decide on the basis of a figure like that from EIA. So that message will work...

Of course China will act more responsible and modern and will stay significantly below US emissions. But they are not encouraged by US to work hard. That is the reason, why I believe that USA will be responsible for human failure in the end:  They are very succesfull in convincing everybody to stopp working hard for the future of the planet.

Policy and solutions / Re: Will Renewable Energy "Solve Global Warming"?
« on: February 21, 2013, 08:15:18 PM »
Jim, that is really extreme disappointing. Only 11(+2) % renewables in 2040??? And that is a "goal"?

Likely China is going to follow the US-way, they might have similar wealth in 2040 and reaching US emission - the world will surely be blown. Even if China will go only to 50% of US-emission/person due to the more strikt laws, it will not help us. I hope something will make USA change their mind or we really can forget all our efforts...

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