ORH_wxman

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.

Yeah jaxa had another 78k increase last night...so I think we can call it on jaxa as we are now about 180k above the min...esp given the rate of ice growth seems to be accelerating in the CAB.

It makes sense anecdotelly, but the lower mins haven't shown to be any earlier than higher mins thus far if we're using empirical evidence. 2007 was actually one of the later mins on record. 2011 was a bit early, but 2012 was pretty late. I think perhaps the open water this season getting fairly close to the pole but still surrounded by a lot of ice on most sides in the CAB helped cause the early min....assuming we've actually reached the min. The smaller finger of open water there was more vulnerable to closing up quickly once we lost insolation. The higher res U Bremen AMSR2 min occurred even earlier than Jaxa so far...it had a min on 9/1.

9/7 would be the earliest extent min on record for Jaxa. I'll have to see what the earliest is for NSIDC.

We're taking geoengineering projects.

And how do you know it would stop? Climate systems have inertia. How do you know what the effects would be? Our understanding of feedbacks is not precise at all What if you started a cooling process and weren't able to stop it where you wanted and it ran a degree of cooling? That's pretty dangerous stuff. Rapid cooling is probably more dangerous than current warming.

On Jaxa which is lower than other datasets since they changed their land mask. I think NSIDC, U Bremen, Hamburg, etc will stay above 4...no guarantee tho. I agree with winter that geoengineering is very dangerous given how much we still do not understand about the feedbacks in the climate as it is.

If we get another winter like we just did then it would be a lot more possible. This year was very difficult despite the early low extent and premature proclamations of a record being likely because average thickness was too high. But we will be going into this winter with fairly low volume so if it torches again and there's also good Fram export then that would load the dice for 2017. But if winter is a few degrees colder than last year then we'd probably have to rely on exceptional weather to gun for the record.

The trash is negligible to sea level rise. It takes 360 billion tons to raise SL by 1 millimeter...the total amount of trash is almost certainly less than that as the amount per year that ends up in oceans is usually measured in the low millions of tons.

I think this year looks worse on the Pacific side assuming the whole ESS arm melts out. 2012 did have a "base" of multi-year ice still left on the PAC/Beaufort side of the CAB that was larger than this year's. Luckily in the winter of 2012-2013, that chunk got pushed westward and helped out with the rebound in 2013/2014 in volume when those summers were cold enough to keep that base of MYI in place. Then 2015 came and melted out most of it in the Beaufort during the torch that summer...and this year, we're seeing the effects of that (along with a warm winter) with the ice melting out fairly easily on the PAC side despite avoiding a nasty dipole. I am a bit surprised at how much ice survived in the Laptev sector given how the ice didn't hold out very well in the ESS....usually the ESS holds out better than the Laptev sector.

Definitely slower than the 80N graph tho. So I would guess that were still a good 20 years away from expecting regular ice free arctics at the min. Though the first occurrence would obviously happen sooner during a year when all the stars lined correctly. Though of course this is assuming that 2C figure I said earlier was correct and assuming the rate of warming did not increase or decrease....which is a lot of assumptions.

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.

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.

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?

Looks like it was displaced a bit too much toward the Asian side though to produce the type of cold we saw in those other seasons. (1996 had the coldest June/July on record and 2013 was top 5) Still, it prevented a record from occurring when the ice was well beyond record lows in May.

Ahhh...right. I don't usually use those since they have no real history (only back to 2013 AMSR2). Though the bootstrap AMSR2 data from U Bremen does look like a slowdown the last couple days: The ice still looks pretty precarious though so I wouldn't be surprised if we see some big drops between now and the min. I don't know if it will be enough to finish below 2011, 2015, or 2007...but we'll see. You can see on the graph how 2015took a really steep dive starting this week.

We gained area on today's update but we didn't gain extent on any of the main datasets. I'm not sure which datasets you are using to get those numbers.

Doesn't he use SSMI/S for 2012 though? That would not be the best comparison. If those numbers are accurate though, then they will show up on most metrics very soon. I'm a bit skeptical on that though. I do think there's higher than normal risk for a late crash given all the marginal concentration....but on the flip side, I could see a pretty big area spike if that stuff near the pole starts to refreeze in the next 4-6 days. That's a difficult area to keep low concentration this late.

CT SIA (or really NSIDC area) is something like 400k above 2012 actually.

You can look at it both ways this year...we had a record warm spring (after a record warm winter) and June actually wasn't that cold...maybe slightly below normal, but it ranked like 19th or something since 1979. 2013 and 2014 ranked in the top 5 coldest. There was unprecedented open water on the pacific side early in the season. So the ice came into this summer in about the worst shape it could have given the starting point at the end of last melt season. Yet, we're not going to come close to the record. On the other hand, July and August have been cold and yet we're still challenging the 2nd lowest season. So that sounds impressive too. It will be a race between the ESS arm of ice melting down and the CAB slush pool refreezing late this month that determines the exact spot we finish.

CT area as calculated by wipneus on the arctic sea ice forum is currently 3rd lowest...just below 2011 and above 2007 (2012 is long gone). So we def still have a solid chance at getting the 2nd place spot. We'll have to see how the ESS does in the next week...we've lost a ton of area in the central CAB just north of the CAA/Greenland recently and that spot can refreeze pretty fast in late August, so I'm guessing we'll need to see that arm of ice in the ESS get hit hard to secure 2nd place.

Area is currently 3.63 million sq km. In order to finish higher than 7th, we'd need to only lose 200,000 sq of area between now and the min as the current 7th place year of 2009 had a min of 3.42 million sq Km. A loss that low from here to the min has never happened I don't think (if it did it was maybe 1997 but I don't have the numbers right in front of me). The 6th place year was 2015 at 3.09 million sq km which is still possible to finish above. So I feel pretty safe saying that we will finish between 2nd and 7th in area. Volume also doesn't bottom out in August. It bottoms in September. At least according to piomas it does.

Way too early to know if it is going to be an early min. The min won't occur until at least a week into September and that is still 4 weeks away. Also, that arm of ice extending out into the East Siberian sea is looking pretty fragile...so the storm may not be good for it. The 2012 storm destroyed ice out in that area...but the difference this time around is that the ice is in a bit better shape there and the storm is occurring deeper into August than 2012 which means colder temps...but the water getting churned up could easily offset that. We'll see in a few days what happens. I'd call it a toss-up right now on whether extent finishes top 3 or not. 5th is certainly a possibility...but so is 2nd. As for area...we're in the same boat. We are currently in 4th place behind 2012, 2011, and 2007...and barely lower than 2015. So it's basically a tossup...we could finish anywhere from 2nd to 7th realistically.

We definitely could have had a legit chance of beating out 2012 if this summer had a 2007-2012 pattern. The ice was served up in rough shape after the month of May. But that June pattern is still so crucial and even with obscenely low extent well below 2012 in May, you need the good dipole or you won't break the record. But that really rough start will still be felt this summer. There's a decent chance still we can get by 2007/2011 depending on the weather at the end here.

I wouldn't classify this summer as good. It was ok. June temps were significantly warmer than 2013 and 2014 despite it not being a classic dipole pattern. It ranked something like 21st or 22nd coldest June since 1979 while '13 and '14 were in the top 6.