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Messages - Michael Hauber

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Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 07, 2019, 04:49:57 PM »

The "intuitive" guess was the posited explanation for the acceleration in 2002 - nothing in the above linked article even tries to touch on that. In fact, I am totally missing the relevance here!

Besides, isn't it totally counterfactual to claim that the loss of MYI somehow causes a flatlining of the annual minimums? I'd have thought it would be exactly the opposite.

When the slowly vanishing MYI was finally mostly gone in 2012, the minimums should have started to drop ever lower! The difficult-to-melt ice was all gone, only the easy FYI left, and minimums should have plummeted. Instead the annual minimums are (most probably) heading steadily downwards or have (quite possibly) stalled.

It looks as if there is no any causal link between the trends in annual minimums and the loss of MYI.

The explanation and timeline, as I see it, for acceleration and then later deceleration runs as follows:

Just prior to ~1998-2000 the flywheel of Ice making it around beaufort gyre and having a life of around 10 years in which to thicken meant large MYI extent and thickness. Nghiem et al 2007 has perennial ice extent slowly decreasing towards 4m km^2. Once it reached that level, the ice in Chukchi, East Sirberian and Laptev was melted out such that each year so it was only first year ice in those regions each year so they melted out every year. Some MYI might move into Chukchi, but it didn't make it around East Sirberian and Laptev parts of Beaufort gyre.



This created crash in thick MYI volume, area quickly declined to 3m km^2 and volume even more rapidly. As thick MYI reduces in thickness, it does not grow back during the winter if it is already above the equilibrium thickness. FYI is saltier and more easily melts out so the increase in FYI area and lower thickness allows more open water formation so more albedo feedback. This drives a rapid reduction in extent.



As it took ice ~ a decade to complete the beaufort gyre, this process goes on for at least a decade til the MYI reaches a new much lower level equilibrium basically squashed up against Greenland and CAA. The centre doesn't melt out so extra MYI is added there, being more or less balanced by some MYI getting squashed out into Beaufort or Nares or Greendland sea where it melts out.

There is only so much MYI that can be reduced in the rapid process before the reductions in MYI has to slow down. Once the MYI loss slows down, this then slows down the extent loss which was following the MYI losses.

This explains both the acceleration and the deceleration.

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Arctic sea ice / Re: The 2019 melting season
« on: August 15, 2019, 07:06:36 AM »
There's a good view for the first time in a long time on the ice that's left in the ESS. I'm absolutely gobsmacked to see how long that ice is lasting. I think I predicted a month ago that it would only last a few more days. Yet today, it's still there... Amazing! That was a good lesson!

https://go.nasa.gov/2OXr2ei

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Arctic sea ice / Re: "Stupid" Questions :o
« on: August 04, 2019, 05:56:11 AM »
Q. Can it? My response to this statement on the 2019 Melting Thread.

There is more than enough heat in the deep water to melt the ice and keep the arctic ice free year round. 

However, the heat can not move upwards through the halocline. 

The halocline is 50 meters thick (at least) and is very difficult to breach.  If it ever happens, look out!   The arctic will be a completely different place.


I've often wondered if/why the thermal conductivity of seawater is insufficient for significant melting of the ice just by thermal conduction, when the halocline is stable.

So let's see...


Consider the year-round loss of ice thickness due to thermal conduction from a 1-degree-C-warmer layer at a 50 meter depth.


ASSUMPTIONS & PROPERTIES:




CALCULATIONS:

Upwards heat flux = (temperature gradient) x (thermal conductivity) = 2e-2 K/m x 0.6W/mK = 1.2e-2 W/m^2

Thermal energy added to ice in 1 year = (Upwards heat flux) x (time in 1 year) = 1.2e-2 W/m^2  x 3.1e7 s = 3.7e5 J/m^2; multiply by 1e-4 m^2/cm^2 = 37 J/cm^2

Depth of ice melted = thermal energy added / (heat of melting x density)
= 37 J/cm^2 / (334 J/g x 0.9 g/cm^3) = 0.12 cm depth



CONCLUSIONS

So the thickness of ice melted over a year in the above scenario is only of order a millimeter.

Indeed, the thermal conductivity of seawater is insufficient to provide significant melting from deep layers of warmer, saltier water below the ice.

4
Arctic sea ice / Re: The 2019 melting season
« on: July 31, 2019, 03:41:39 AM »
Given the accuracy of past Slater projections to minimum, a record should not happen this year, but I don't think a Slater projection for 2012 is available.

Slater's prediction for 2012 can be seen at http://cires1.colorado.edu/~aslater/SEAICE/Slater_AGU_2013_poster.pdf.


His model did successfully predict a record low extent minimum 2012, but not as low as reality. The predicted 2012 minimum was just a bit under 4 million km2 - which is also what the Slater model predicts for this year.

Given its similar predictions for the extent minima in the record year 2012 and in 2019, the Slater model can't be said to rule out a new record low extent this year.

5
Arctic sea ice / Re: The 2019 melting season
« on: July 30, 2019, 07:38:12 PM »
Note to Oren .. Geronto's  NSIDC graph yesterday showed ESS this year in a clear lead .. bbr was being factual with his CAPS .. but facts vary .. not just in Trump's world .. b.c.
Thanks b.c., I didn't think to check that, though it seems I was correct anyhow. NSIDC area chart shows the same behavior, 2015 and 2017 on same leading path as 2019, with 2012 and 2016 coming from behind and overtaking them soon.

Don't forget 2007, which was much lower than the other years for the ESS at this time of year:



(Image from Wipneus' regional NSIDC area graphs.)

6
Arctic sea ice / Re: The 2019 melting season
« on: July 26, 2019, 09:46:51 PM »
I think it is quite obvious now that there is not going to be a record this year just a second place. If you compare 2012 and 2019 and consider  only the pink/purple area (as the green and yellow melts out in 1-2 weeks anyway) then you can see that 2012 has a huge adventage: almost no purple south of 80 degrees, while 2019 has much more of that harder to crack ice. Also, the Atlantic front is way behind in 2019. I know that we will see about 5 days of hot-sunny weather but beyond that it seems cold and cloudy again.

attached: 20120725 and 20190725

7
Arctic sea ice / Re: The 2019 melting season
« on: July 26, 2019, 07:26:34 AM »

It hasn't been relatively cold. You are just making sh*t up over and over again.

I'll invite you to read Gerontocrat's daily summaries for the entire melting season.

Almost every day as part of his boilerplate analysis, he includes the Arctic temperature anomaly. When historian's go back and look at his entries, they will be interested to find that the range of temperature anomalies was always positive from April through June.

In mid July for the first-time they will see for the first time...references to zero degree temperature anomalies. Interesting...I guess Gerontocrat is making shit up too?

No. For some reason, there is denial on your part that momentum has slowed since mid-July and you're getting hostile about it.


8
Arctic sea ice / Re: The 2019 melting season
« on: July 24, 2019, 06:05:53 PM »
Re: the icebreaker.
According to this article the ship had to return due to a leakage in the propellerhouse. The thicknes of the ice was not a problem. The icebreaker was built in Italy and was one year late due to construction problems, according the article. https://www.nrk.no/troms/forskningsskipet-_kronprins-haakon_-skadet-etter-mote-med-is-1.14636312

9
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 29, 2018, 04:57:18 AM »
The soil and rock below us cannot absorb as much water as the ocean, but it still can absorb quite a lot.Brown Ocean effect

Trivial correction: Should presumably have been "as much heat" and not "as much water".

10
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 17, 2018, 08:42:48 AM »
JAXA ARCTIC EXTENT 5,248,792 km2(August 16, 2018)

For those who do care a flying whatsit, herewith some more extent data.

Just to add to Juan's post...

- Extent is now 84 k km2  (1.6 %) below the 2010's average extent on this date,
- and 112 k (2.1%) above 2017 (which is about to start a series of below average extent losses) ,
- Extent loss to date is now 286 km2 (3.2 %) below the 2008-2017 average, with 89.6 % of the average melting season done.

Resulting minimum from average remaining melt is  4.21 million km2, (excluding 2012 from the average gives 4.24 million km2 - an insignificant difference). Range of results from last ten years remaining melt is 3.96 to 4.58 million km2 - also a narrowing range. For a minimum at 2nd lowest remaining melt needs to be about 14% above average. For a new record low remaining melt would need to be 2.07 million km2 as opposed to the average remaining melt of 1.03 million km2, i.e 1.04 million (100 %) above the average. Not feasible.

Of interest (?) is that in 2012 melt from this point was just 0.26 million (25%) above the average remaining melt.

That 2017 feeling wanes and waxes- extent losses are only slowly (or not at all) catching up on the slow melt to date and NSIDC Area losses have slowed significantly. There is, on average, just 10.4% (27 days) of further extent loss to go. Could the melting season last a bit longer than that - Yes.  On the other hand, could extent loss sharply reduce? Yes.

A September minimum in the range of 4.00 to 4.50 million km2 seems probable, with the result of least drama at 0.2 million km2 above 2nd place, 0.2 million km2 below 2017 and about 1 million km2 above the 2012 outlier.

11
Arctic sea ice / Re: The 2018 melting season
« on: July 03, 2018, 05:08:36 PM »
NCEP Reanalysis temperature data for June (since 1948):

Arctic: 6th
Atlantic: 46th or thereabouts
Siberian: 1st (more than 1° C higher than previour record)
Pacific: 12th
Canadian: 37th or thereabouts

12
Consequences / Re: Global Surface Air Temperatures
« on: June 21, 2018, 03:25:35 AM »
The image just provided uses Fahrenheit while the one above it uses Celsius.

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