csnavywx

Can gradually see the late season ice pack of the next decade taking shape this time of year. 2016 and this year are good examples with a solid compacted half moon-shaped slab up against the CAA where the remaining MYI is located and an arc of weakened FYI from the Beaufort side right across the pole. A warmer summer would have melted that arc and left the MYI in place.

Weather gets much more hostile over the next few days, which will open the Pacific bite up even more, but it's much too late in the season for any of the compacted FYI/MYI to be melted away. It could definitely make a run at tying last year or 2007, though and leave a lot of scattered patches at the minimum. As we saw last year, that tends to re-freeze pretty quickly in late Sep and Oct. Just not quite warm enough to maintain open ocean that far north yet.

On 7/25/2017 at 7:02 AM, chubbs said:

Interesting chart from Wipneus on the ASIF today showing the area of various ice thicknesses on July 22. 2017 lags in the thinnest categories but leads in the thicker. Wipneus notes that 0.26 on July 22 always melts and 0.71 sometimes melts in severe late summers. So a range of outcomes is still possible this year depending on weather.

I'm fairly convinced that if you start with this year's April volume and add a 2012 summer, you'd get damn close if not hit the 1M "near sea-ice free" criteria. It's taken a solid 2 months for 2012 to cut that lead down (though most of was during late May-June). Sept 2012 only had 2800km3 left at the min. Rob it of 2K in April in the thicker/colder areas like this year and that might be enough to tip the balance. It's not a high chance at this point by any means, but I think it's starting to cross the 5% threshold.

2012's August losses were one of a kind ridiculous. EOSDIS doesn't show the kind of weak, broken ice pack that would be susceptible to mass extent/area loss in August like 2012 (and to some extent last year). With this turbo +AO remaining in place into the extended, there's a chance we could get get above 5M for extent in Sept if that pattern doesn't break appreciably.

-377k on area from the 5th-7th, making total losses from 30 June - 7 July around -1.1M. Wouldn't be surprised to see a brief stall or slower losses for a couple of days as the cyclone in the CAB makes its way south. Upcoming pattern features a windy push of subtropical air (via omega block and a flanking cyclone) into the ESS, Chukchi and Beaufort and perhaps into part of the CAB. That should get steep losses rolling there. Potentially big push coming on the Atlantic side if the ensembles are right, which might set up some hefty losses in the D6 timeframe. I hesitate to go much further, but the GFS, GEM and EC ensembles do seem to favor a TPV position near/over the Hudson/CAA/Baffin area. With a strong subtropical ridge to the south, it's possible this configuration gets stuck in a tripole and exposes the Atlantic front to hefty losses for the first time this season. Ice thickness is precariously thin on the Eurasian side, so I wouldn't be surprised to see that fold like a cheap rug. The silver lining is that configuration would shut down export.

The EC op and EPS paint an interesting picture. After the current TPV starts migrating away at t+72, a big subtropical intrusion starts from the Russian side over the ESS. Temps at 700mb rise to 5+C and 500mb temps get above -10C, denoting the deep subtropical characteristics of the airmass, along with high TPW/theta-e. Most importantly with the strong WAA is the forecast wind strength and fetch, which would enable these temps to mix down effectively. The EC OP is a knockout blow from D5, but I won't speculate much past that due to the limited recent model skill.

Definitely a potential watcher for the Pacific half of the basin.

On 7/5/2017 at 4:58 PM, ORH_wxman said:

Finally melting all that snowpack on the CAB ice and getting melt ponding. The bigger question though becomes is this happening too late?

2013 saw similar losses in the same period (670k) before stalling later in the month. OTOH, years like 2008 (the closest match to 2017 for area on June 30th) decided to go nuclear a few days later (about July 5-9 losing almost 800k) and finished pretty low...albeit still around 3.00 million sq km.

It's a good question. Looking at EOSDIS shows much of 2013's ponding on this date was confined to the periphery while much of the CAB snowpack survived until late July. This year shows ponding deep into the CAB -- not as extensive as 2012, but not far terribly far off either. This year is lagging behind 2012 in the Kara/Barents and Beaufort in open water coverage but ahead in the Chukchi and ESS.

The EC/EPS is backing away from a strong PV in the D5+ time period. Looks like the seasonal pattern of rapid switching will continue.

I'm really torn on how to go for minimum. Maybe a blend right down the middle with a large area of broken/partial coverage (not too dissimilar from last year). Volume not too dissimilar from 2012 (maybe slightly above) with extent well above.

After a slowdown with the PV pattern last week, the basin has lost-724k in area from the 30th-4th (on NSIDC).

PIOMAS actually stayed slightly below 2012 -- or a statistical tie, so it definitely hasn't lost much ground over the past 2 weeks. Most of the gap closing occurred early in the month.  Current anomaly is the lowest on record. As far as the state of the pack is concerned -- it's definitely weaker on the Pacific and ESS-Laptev front and definitely stronger on the Atlantic/Kara side.

The dipole shuts down after D5 (as far as the OP runs are concerned) and a cool PV pattern is dominant on the ensembles. This year has waffled rapidly back and forth, so we'll see if that continues.

Ironically, a great deal of ponding has shown up over the past 5 days on EOSDIS. The strong winds, WAA and chinook-type event off the Kolyma range on the forward flank of the storm did a great job of breaking the inversion and eradicating snow cover, jumpstarting melt-ponds. The O-buoy 14 pictures show that as well, going from solid snow cover to solid melt ponding in less than 2 days. Melt should slow considerably for the next 3-4 days. However, the upcoming pattern has downsloping flow off the Brooks range for an extended period, which will serve to push the Chukchi/Beaufort front back pretty quickly.

4 hours ago, ORH_wxman said:

The last two winters have definitely been poorer for first year ice with much warmer conditions than the previous 3 winters...though the thermodynamic thickening curve would still have the FYI achieving most of its possible thickness even in those warmer winters...we probably need another 2C or so to really start seriously denting the FYI thickness. I do wish we had better subsurface data on the SSTs up there, because I'm wondering if last year's El Nino played a role in the rapid melt during the 2nd half of the summer by increasing the flow of warm subsurface into the pacific side of the arctic...since last year didn't really have favorable melt weather outside of a very intense dipole for about 2 weeks in August.

There's evidence of significant Atlantic water shoaling over the past 5-10 years. Neven's site had some stuff posted from this paper: https://www.ncbi.nlm.nih.gov/pubmed/28386025

I believe the AW layer was found to have shoaled about 50% of the way to the surface in the last decade on the Eurasian side -- hence the paper's statement of a significant fraction of forcing coming from the ocean now. The issue there is that with additional shoaling, even weaker summer storms will be able to tap that water layer and cause it to interact with the near-surface layer. That may have been part of the issue last summer. I'm pretty sure the Pacific current played a role there too -- but as you say, it'd be nice to confirm that.

Your comment on winter warmth is about right. This winter's FDD anomaly total was around -1750. At around 2000, it begins to seriously undercut spring thickness and at 2500+ maintaining FYI gets pretty untenable even through a cool summer. There isn't much buffer room left there. The good news is that last winter was pretty extreme compared to any other winter, so there's a good chance we'll get a mean-revert this year.

Gotta go back to Aug. 2012 to find a cyclone as powerful as is being progged next week at this point.

Just now, bluewave said:

The -425 m PV is one of the strongest that we have seen in June. So yet another June post 2012 without the strong 2007-2012 dipole making an appearance.

 

 

 

 

 

 

Yeah, the EPS is now pretty adamant that just about the entire basin goes cold. I'm beginning to think the current +PDO/warm ENSO stretch is inhibiting any lengthy dipole development. There have been a couple of papers hinting at this outcome recently. You had one a couple years back relating to this issue as well, I believe?

2 minutes ago, ORH_wxman said:

The area losses look like they are mostly coming from Hudson Bay and perhaps the Kara. The Kara is more meaningful, but Hudson bay can deceive us sometimes in both directions...the main basin looks pretty high concentration to me right now.

 

Of course, we don't have SSMI/S area data right now...that's really the most important one for predictive purposes because unlike AMSR2 data, it is sensitive to melt ponding.

Good point about the Hudson. It's been wrecked pretty hard this season and probably can only contribute for another 10 days before there isn't much left (it's almost all grey ice at this point). EOSDIS does suggest some ponding has developed in the ESS, Laptev and perhaps the Barents, but given the colder weather on the way, I doubt they'll contribute much over the next 10 days.

Very solid area drops the past couple of days (per Wipneus's homebrew calcs). -192k for the 14th and -128k for the 15th.

Couple more days of decent drops are probably coming before cooler weather sets in. It will then depend on exactly where that advertised TPV sets up and how strong it is. A TPV positioned near the pole will of course result in much slower losses -- whereas a position over the Laptev or coast there will hasten Fram export and cause the Chukchi/ESS open water front to rapidly advance. Either way, it's probably still better than the dual ridge we had over the past week given the temperature drop.

Looking at individual years, it doesn't show up every year, but it shows up quite a bit from here on out. Some years are just as cold, if not colder this year.

Just out of curiosity, I went through the CCSM4 output on Climate Reanalyzer and looked at that region out through time. Something interesting popped up:

If I expand the timeframe to 2021-2040 vs 2001-2016, it's still there:

12 minutes ago, ORH_wxman said:

Out of curiosity, I plotted the May average temperature for the Siberian region....and it definitely is more of a 1990s profile (and 1980s/1970s for that matter)...so the flukish reversion to a cold May explained the big snow cover anomaly there.

 

Wow, that's a big drop. Pretty surprising, even with the high variance.

25 minutes ago, ORH_wxman said:

I'd say looking at the data that you have to go back to 1996 to get snow cover this widespread on the Siberian coast into mid June.

 

Thanks for the link...I assume you are talking about the level of "blueish" tint to the ice pack between years? I haven't really used this product before, but it's pretty cool. I've mostly used the false color products from AMSR/AMSR2 over the years with the area data from SSMI/S of course since it's a continuous dataset.

Yep, this exactly. It's not a quantitative thing by any means, but still useful, imo. It only goes back through 2012 unfortunately, but it's got enough to start making comparisons.

*Edit for typo.

4 minutes ago, ORH_wxman said:

It looks like the high snow cover anomaly on the land in Siberia is maybe having an impact on the melt on that side of the ice pack too.

Agree here. There's a big visual difference in ponding between years in which that snowcover disappears early and years like this one and 2013 where it takes a while longer. We haven't seen that much snow cover along the Siberian coast this late in over 10 years, maybe since the 90s.

3 minutes ago, ORH_wxman said:

Do you have a link to the daily plots?

Are those the ones from jaxa?

Sorry, should've been more clear, I'm referring to EOSDIS Worldview and scrolling between years on this date:

https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2017-06-12&z=3&v=-3714337.5732286554,-1744121.4245445705,4149982.4267713446,2552582.5754554295

Posted on Neven's forum. Definitely fits the bill of high snowfall retarding melt. Going to take a good dipole pattern to reverse that.

1 minute ago, ORH_wxman said:

We need to get bigger area drops soon to stay competitive with the lower years.

I don't really think that's going to happen for a couple of weeks at least. Maybe if the dipole showing up at D5+D6 comes to fruition. One would have figured the "bridge ridge" of the past few days would have done more damage, but that just shows how much snow is still there. Even 2013 had more melt ponds at this point looking at the daily worldview plots, even if it did have a lot less open water.

A 2007 pattern starting in late May would have done it this year I think. But that's an exceptionally bad pattern -- ergo pretty rare. This year is a bit wierd. We've got record low starting volume, but high adjacent land snowcover and a decent snowpack left on the ice in most areas. There isn't as much blue ponding on Worldview this year as last year or 2012, for instance, but there's a lot more open water in the ESS and Chukchi. I think the warm winter had the effect of dumping more snow on the pack than we saw in previous years. This has a lot higher albedo, retarding initial melt, but once that protective covering is eroded, the underlying thinner ice is melted more quickly.

Not really sure which way to go this year because of the confounding factors. I don't think big domes of high pressure are going to necessarily get the job done in the melting department though. Wind and sun is really needed to take care of the snowpack and weaken the inversion and break the low level cloud cover that sets up as a result.

12Z EC pretty much goes nuclear.