chubbs

Currently Antarctic sea ice is even more unusual.

Looks like 2016 volume caught-up to 2012 by late October. Record low volume likely in Nov.

3 hours ago, nflwxman said:

Right.  In the near term, the record slow refreeze means very little in terms of "climate feedbacks."  The extent in May and June have much larger implications on lasting arctic warmth due to the sun pouring in at that time.  The argument can be made, however, that a record slow refreeze could potentially cause a less solvent ice pack moving into next melting season.

The climate feedback maybe smaller this time of year but the mid-latitude impact is greatest through warming of the Arctic leading to a weaker jet stream. Could be another good I95 snow year.

9 hours ago, tacoman25 said:

A little bit of inconsistency going on in this thread. In recent years when we set a record for fastest fall freeze-up, or reached a high point for that part of the fall, we were told it was meaningless, the min is what really matters.

Now we have a people saying record low ice 2 months past the min is just as meaningful as a record min. 

As long as the Arctic Ocean completely freezes in winter, record melt extent will always produce record re-freeze. With all the open water in the Arctic Ocean this year, we will get a record late Fall/early Winter re-freeze at some point.

Global sea ice extent  has moved far outside the historical envelop in the past 3 weeks. Unlikely to get much better in the next week or so with PV splits at both poles.

NSIDC extent for Oct 29 from Mohyu blog. (1000 of square km)

              Arctic      Antarctic     Total
2015      8444       17748       26192
2016      7111       16620       23731

2016 has 2461 x 1000 sq km or 9.4% less sea ice than this date last year. This is roughly 0.5% of the earth's surface.

This just out (behind a paywall) . Timely for this fall's unusual arctic circulation. Note positive feedback between sea ice loss and circulation changes leading to increased heat transport to arctic.

On the atmospheric response experiment to a Blue Arctic Ocean

Tetsu Nakamura1,2,*, Koji Yamazaki1,2, Meiji Honda3, Jinro Ukita3, Ralf Jaiser4, Dörthe Handorf4 and Klaus Dethloff4

http://onlinelibrary.wiley.com/doi/10.1002/2016GL070526/abstract

Per Jaxa, looks like antarctic extent is also at a record low. First time ever for both poles at same time?

Saw this Wipneus plot of PIOMASS minimum volume at the ASIF. This year ended up close to 2010 and 2011 and not far below the linear trendline.  If we follow the linear trend, 2012 will be a normal year by 2022.

6 hours ago, PhillipS said:

Keeping in mind that SMB is only half of the mass balance equation, it looks like 2016 was the fifth worst melt season of the instrumental period, and the second greatest season for runoff.  Just eyeballing the graph it looks like there is a long-term decline in snowfall but I don't know if that's due to less precipitation overall or more precip falling as rain.

Here's the GRACE plot of total mass balance since 2003.  I expect that 2016 will have a net mass loss of around 300 Gtons (300 km3).  

 

The figure below from a recent paper below shows how glacier discharge (D) has increased and surface mass balance has decreased since 1990 causing an increasingly negative Greenland mass balance (MB). Comparing the SMB estimates in the chart below to the chart posted above, the long term trends are similar but there are some differences in the relative ranking of individual years.

http://www.the-cryosphere.net/10/1933/2016/

Here is a summary of the modeled surface mass balance of the Greenland ice sheet for the 2015/16 melting season. Strong melting was partially compensated for by above average snowfall.

http://climato.be/cms/index.php?climato=the-2016-melt-season-over-greenland-as-simulated-by-marv3-5-2

20 hours ago, ORH_wxman said:

Yeah it is interesting they mention the upper ocean heat...I wonder if the exceptionally strong El Nino made it worse this summer than recent years.

Northern oceans have continued to warm while el-nino fades cooling the tropics. See also:

http://www.esrl.noaa.gov/psd/map/clim/sst.anom.anim.year.html

1 hour ago, ORH_wxman said:

Now that we've reached the min it looks like on all metrics, time for a quick review.

 

I posted predictions for CT SIA on June 30th this year like I've been doing since 2013. For the first time, this year fell outside the 5-95% confidence intervals. A 5% result would have been a min of 2.58 million sq km on CT SIA, and we finished down near 2.42 million sq km which was actually closer to 2012 (the lowest year) than 2011 (2nd lowest). I'll get back to this in a minute.

For extent, it is a bit harder, but loosely converting area to extent made the low of roughly 4.1 million sq km (on NSIDC...a bit lower on jaxa around 4.02) a result that would occur about 20-25% of the time given the information we had on 6/30. So the extent was low, but not well outside of the typical confidence intervals.

Getting back to the extreme area result....the first culprit you would look at is the weather. However, the weather wasn't hostile to the ice in July/August this summer. There were a few hostile periods, but they were largely transient and we would have needed to see off-the-charts extreme. So weather isn't really a valid explanation. That leaves two other variables that may have played a large factor....bottom melt and reduced ice thickness from an exceptionally warm January-May period. PIOMAS didn't really have exceptionally thin ice, though the CAB region close to the pole was a bit thin and this is actually where a lot of the area damage occurred as we had a big fragmented pool of floes that was the major contributor of the area loss in August. Cryosat2 was a bit thinner here as well. But we've had very thin ice here before too that experienced summer weather worse than 2016 and yet we didn't see this. In 2013, the ice was significantly thinner in much of the CAB region near the pole, though it did have weather more favorable for ice retention than 2016 did. But still, that leads me to believe we may have had more bottom melt too this season. We don't have a lot of reliable data on this. Some scattered buoys is about it. There is some literature that suggests stronger El Ninos causes an influx of warmer waters at depth into the arctic ocean, but it's not very robust.

 

At any rate, it will be interesting to gather more data as it become available in the early winter with cryosat2. I think a combination of exceptional warmth in spring and above average bottom melt likely contributed to the extreme result. Something like this may have to be taken into account in the future when making predictions.

It is surprising how close CT SIA came to 2012. The series of storms in August may also have played a role by enhancing bottom melt.

NSIDC extent dropped 120k on 9/6 to 4083k clinching 2nd place.

9 hours ago, donsutherland1 said:

That's the way it appears. That's why I still think there's a reasonable prospect that the minimum will be under 4 million square kilometers.

Yes, good job flagging 4mil as a reasonable prospect at the start of the year

4 hours ago, donsutherland1 said:

Now that August is ending, a closer look at the Arctic sea ice extent figure is in order.

The 8/30 figure (JAXA) was 4,302,421 square kilometers. If that were the minimum, it would rank as the 5th lowest on record.

However, it is all but certainly not the minimum. A number of scenarios for the minimum figure:

Smallest decline from 8/30 to the minimum (2002-15): 4,140,726 square kilometers (would rank 3rd lowest)

Largest decline from 8/30 to the minimum (2002-15): 3,793,311 square kilometers (would rank 2nd lowest)

Average decline from 8/30 to the minimum (2010-15): 4,007,579 square kilometers

All said it appears very likely that 2016 will see the 2nd or 3rd lowest Arctic sea ice extent minimum on record. There remains a reasonable possibility of a minimum figure below 4 million square kilometers for only the 2nd time on record (JAXA). 2012 is currently the only such case.

Would expect above average extent losses to close out the melt season due to the large areas of low concentration ice, good melting momentum, and relatively mild weather to start September particularly over the Laptev.

1 hour ago, ORH_wxman said:

What is the rate of cooling for the entire basin? 80N is really narrow region. It needs to cover the large region of where FYI regenerates volume. 

Here is 70-80N on the Pacific side covering most of the rest of the Arctic Ocean. There are some year-to-year differences, particularly this year, but the overall trend is similar.

21 hours ago, ORH_wxman said:

 

We really need winter to warm a lot more to start really thinking about "ice free" (which is less than 1 million sq km).

 

Right now, the low sea ice in the autumn actually acts a negative feedback for volume regeneration in winter once we lose the sun. That open water sheds the excess heat pretty effectively and most of the volume gain occurs in the first couple months of refreeze, and then tails off as ice reaches the asymptotic point for thickness gain. Throw in a couple decent patterns in the winter (like we saw in 2012-2013 and then again in 2013-2014), and you end up "regressing" away from the ice free arctic and have decent volume bounces like we saw those years which means you have to "start over again" in trying to shed that volume. The last two years have trended back downward and lost back that volume gain, but they can reverse with a decent winter pattern and a non-dipole summer.

 

I forget where I read this...I'll look around...but someone had shown that we really need winter to warm about another 2C to really be able to get ice free arctic. If everything happened perfectly in one season (abnormally warm winter coming off a bad melt season...then another horrendous pattern in melt season), we could maybe achieve it within a decade? Hard to say, but we want to see winters warm enough to where we aren't realizing the full regeneration of volume from first year ice.

Cool season 80-90N has warmed by roughly 4C in the past 20 years, so unless things slow down, 2C is not that far away.

4 hours ago, ORH_wxman said:

CT SIA has locked in 2nd place now...it fell below the 2011/2007 mins today. It would need another 600k or so to catch 2012, which isn't happening. (though I should never say never when it comes to these things...but it would be crazy to have that much loss this late in area...esp with that big area of low concentration near the pole which will likely refreeze pretty soon and be a headwind on further area losses after the next few days) Looks like extent though is lagging somewhat. Still uncertain whether we will make it for top 3 in extent.

 

I wonder if that poster last page still thinks my prediction range of 2nd-7th is still too low?

Down 360k in the past 3 days.  With this late area drop, looks like 2016 is going to separate from 2011/2007 on CT SIA.

On 8/23/2016 at 11:01 PM, csnavywx said:

Probably surface pond re-freeze. The upcoming pattern features a +3-4SD ridge (570-582 dam) over the CAB and a -2SD low near the Kara, so the upcoming week should feature some significant late losses. It may be enough to lock a 2nd place finish, but we'll see.

Could also be cloud/precip/ice movement since it reversed last night with a 147k amsr2 area drop. Day-to-day trends have been variable but area is still dropping at a good clip averaged over the past week or so.

1 hour ago, frontranger8 said:

It was actually prior that I said that. Probably depends on how long the dipole persists. Hard to say, given that it's a pretty destructive pattern, but coming so late in the season. I'd probably say 3rd-5th is most likely at this point for area, at least.

Yes dipole would be much worse in June or July. I favor 2 or 3 on area.

10 hours ago, frontranger8 said:

And that pattern was much different than the one we've been in the past few days. Much smaller cyclone, stronger, and not nearly as cold.

Looks like a dipole develops next, though, so should see losses pick up again soon. But we're well past peak melting season, so that's the good news (if you're rooting for ice survival rather than annihilation).

 

You were thinking 4-6'th at the start of the stormy period. Is that still your call?

Big area losses in the CAB the past couple of days. With the stormy pattern forecast to persist for the next week, may get open water close to the pole.

Per the PV pattern, 12z euro/gfs forecasting strengthening low moving from Laptev/ESS to CAB in 4/5 days, euro bottoms out at 966, gfs at 971.

Hoth, on 07 Dec 2015 - 7:02 PM, said:

1) Do you know of any peer-reviewed literature out there that provide a percentage of warming that is directly attributable to Man’s activities? I’ve never seen anyone offer a quantitative breakdown or range.

Per chart below, the IPCC estimated that almost all of the temperature increase since 1950 was due to man-made forcing.

2) The article you posted above states that the earth is even more sensitive to carbon dioxide than originally thought. Why then, since carbon emissions have been rising almost exponentially for decades with the rapid development of BRIC nations, has temperature maintained a more or less linear rate of increase? (Some might say there’s been a pause). Shouldn’t such sensitivity and strong correlation suggest we should have observed rapid temperature increase for some time?

Per chart below,  temperature is well correlated with atmospheric CO2. Note that GHG forcing is proportional to the log of CO2.  Other man-made GHGs like methane and CFC's also have an impact as well as aerosals which have a cooling effect. The rate of increase in man-made GHG forcing has actually slowed a little since the 1980s due to the Montreal Protocol which dramatically reduced CFC emissions and a slowdown in the rate of methane increase.