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Messages - Brigantine

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1
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 18, 2019, 10:03:43 PM »
Please, keep posting them!
This is the first thread I always open when I reach ASIF.

Thanks to all that make this thread so informative!
+1. This is the first place I come to as well.

2
Arctic sea ice / Re: September predictions challenge 2019
« on: June 15, 2019, 12:53:14 PM »
4.25-4.75 jaxa
4.50-5.00 nsidc
OK. But what confidence level?

Since there's still time, I'm revising my JAXA prediction:

June:
JAXA 3.75 - 4.25 medium confidence (down from 4.00 - 4.50 medium confidence last week)
NSIDC 4.25 - 4.75 medium confidence (no change)

Things progressed more than expected in the last week! (though not extent data)

3
Arctic sea ice / Re: September predictions challenge 2019
« on: June 12, 2019, 12:30:08 AM »
To enter, post guess and confidence in this thread before the closing date of the poll.

When is the deadline for June predictions in this thread?  Last year the deadline was 16 June, 23:59 UTC, is it the same this year?
For context, the polls last year closed:
JAXA: 2018-06-15 23h52m49s UTC
NSIDC: 2018-06-12 22h10m19s UTC

So basically the deadline for predictions was 24 hours after the later of the polls closed.

This year:
JAXA: 2019-06-11 18h24m20s UTC
NSIDC: 2019-06-11 19h45m19s UTC

I only posted in this thread some hours after the polls closed, but linked to predictions (including confidence level) I posted in the poll threads. Those posts were last edited on June 8. Please let my prediction qualify!  :)

4
Arctic sea ice / Re: September predictions challenge 2019
« on: June 12, 2019, 12:19:13 AM »
June 2019

JAXA: 4.00 - 4.50 medium confidence
NSIDC: 4.25 - 4.75 medium confidence

5
Link to Last year's same poll.

I just came back to ASIF after not keeping up for a few months... because poll season!

I have a lot of reading to do before I decide on a number... things like how well June anomalies correlate with September, what the ice surface is looking like this year and how it compares, etc.

UPDATE: relevant comment on the state of the ice surface, with links to relevant data. [HT Michael Hauber]
UPDATE 2: relevant comments on melt onset / momentum. [HT Neven]
And SMOS 10 year comparison [HT slow wing]

And then here's last year's predict-o-matic [HT Ned W] including confidence intervals. Adjusting for current JAXA data [HT Juan C. Garcia], 2019 minimum should be 4.02 +/- 1.26 (95% CI) based on predictive power of June 7 extent alone.

Provisionally voted for 3.75 - 4.25 atm, I'm thinking medium confidence.
Raised it to 4.00 - 4.50 after looking at that SMOS beige pixel count graph.

6
Arctic sea ice / Re: The 2018/2019 freezing season
« on: December 13, 2018, 12:03:04 AM »
Per CIS, the Parry Channel is mobile again.

Also, there's this one ARGO float sitting in the warm current NE of Svaalbard (~82N 39E).
It's taking profiles every day, and it's quite Atlantified there.

7
Consequences / Re: Volcanoes
« on: November 29, 2018, 12:13:17 AM »
If it's at 1/17 Hz and no other frequencies, then I'm not at all surprised that no one felt them.

Slow Slip Earthquakes are a relatively recent discovery, 16 years ago or something. AFAIK they aren't very well understood yet. I have a feeling this 1/17 Hz Mayotte event is going to teach us a bunch of things we didn't know yet.

For now I'll just call it the Magma Flute  :P

8
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: November 23, 2018, 08:26:59 PM »
Excuse me if you consider this cherry-picking, but the extent and area growth of late seems to me extraordinary and insane especially during this out-of-control climate change we keep hearing about.  8) 8) 8) 8) 8) 8) 8) 8)

I imagine the the 1980's average to be an average of essentially 10 differently timed steep rises. The effect of averaging then takes all the steepness out of it.

On this date, maybe 5 years in the 1980's were mostly done already and thus growing slowly again, 1 was rising steeply like 2018, and 4 had not picked up the pace yet and were still low.

It would be interesting to see a plot of extent vs growth rate, with time omitted. Then we could see if the growth rate is unusual at this stage of the S curve.

Regardless of the growth rate, it's fair to interpret that the freeze is happening extraordinary early relative to the last 20 years.

9
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: November 21, 2018, 10:53:33 PM »
Specific predictions are good. We like them, and it's a shame none of the doubters made a specific prediction with a number on it (other than "normal" values, and iirc someone said 75% extent on Dec 1st).

Your calibration was just a bit off this time. As if it was a 5th percentile 'highest plausible' value, rather than a 95th percentile confident prediction. This sort of calibration is what the September Prediction Challenge was about - which I very much approve of.

I'm considering making a prediction on whether / how early we'll observe mixing to 400m+ depth in the Sub-Polar Gyre in February/March. If I do make a prediction I'll probably get egg on my face too :P

10
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: November 21, 2018, 10:05:59 PM »
Not the same Hudson Bay region as used in other products - This one includes a chunk of the Labrador Sea, and excludes half of Foxe Basin.

But it's at a 25 year high for the date (same week), and by a reasonable margin.

It would have been quite impressive... but then bbr set the anchor at 75%, and there's a long way to go to get there yet  ::)

11
Arctic sea ice / Re: The 2018/2019 freezing season
« on: November 20, 2018, 10:40:21 PM »
The garlic press is now closed, according to the Russians. (but if Canada disagrees tomorrow, I'll follow them)

Svaalbard must be an eerie place at the moment - No light, (sun 6*+ below the horizon at all times) but at the same time no ice.

12
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 07, 2018, 09:22:26 PM »

Why would a weaker AMOC lead to more transport up Norway instead of Labrador?
My understanding of that:

1) Overturning happens when the surface water becomes (slightly) denser than the intermediate water beneath it
2) Weaker OC implies a water column that is less dense (particularly in the surface layer)
3) This further implies a higher sea surface height (more like a less pronounced depression in SSH)
4) Gradients in sea surface height influence ocean currents, particularly in areas where the sea bed is at ~500m depth - such as the ridges from Iceland towards the SW (along the Mid Atlantic Ridge), and to the Faroe Islands, and also the entrance to the Barents Sea and the ridge NW of Svaalbard

So all else equal a stronger OC in the Sub-Polar Gyre (S tip of Greenland) pulls more of the ex-gulf stream water in the Iceland/Faroe Islands region towards Iceland and spiraling into the SPG, instead of towards the Faroe Islands and up the Norwegian coast. Stronger OC in the area around Jan Mayen pulls more warm(ish) water into that gyre instead of into the West Spitzbergen Current and the Barents Sea.

Conversely, a weaker AMOC in both gyres allows more ex-gulf stream water into the Arctic and Barents.

Basically that ~500m deep ridge from Scotland to Iceland, and SW along the MAR, is a perfect switch that responds to small changes in water density in the deep water regions surrounding it. In deeper water, currents are perpendicular to SSH gradients like wind following isobars, but in shallow water currents can just go from high SSH to low SSH.

13
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: September 19, 2018, 10:32:44 AM »
Reading off the graph:

Sept 17: 4.49M
Sept 18: 4.50M

I don't know how to get the exact figures... but our 2018 minimum is in the 4.25-4.50 bin and is now into 7th place.
(below 2008's minimum)

14
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: September 09, 2018, 06:19:23 AM »
2018 is now below the 2010 minimum.

2003     5933760
2004     5683663
2006     5625046
2005     5179300
2009     5054055
2014     4884120
2013     4809288
2010     4622092
2018     4609439 [to date]
2008     4500623
2017     4472225
2011     4269199
2015     4257003
2007     4065739
2016     4017264
2012     3177455

15
Arctic sea ice / Re: What the Buoys are telling
« on: August 29, 2018, 08:56:05 AM »
It still has a location reported for 2018-08-29, so it's not 1).

2) would be an interesting theory if it had been moving consistently in one direction and then just stopped... but it looks like it's last movements have been a bit back and forth in no particular direction, but over a range >> 1.4km.

So 3) seems most plausible to me, but I haven't looked at nearby weather data or anything.

One thing I found interesting, last time I looked the profiler was ~220m deep, in water 200<depth<500. Now it is at 477m in an area close to the 500m isobath. Not just the cable, but probably also the profiler itself is dragging along the sea floor.

16
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 29, 2018, 08:26:47 AM »
Now below the 2013 minimum.

2003     5933760
2004     5683663
2006     5625046
2005     5179300
2009     5054055
2014     4884120
2013     4809288
2018     4804103 [to date]
2010     4622092
2008     4500623
2017     4472225
2011     4269199
2015     4257003
2007     4065739
2016     4017264
2012     3177455

17
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 27, 2018, 11:33:08 AM »
Can someone post the resulting minimums of JAXA extent data in previous years?

Jaxa September minimums for the past 15  years have been:
(from the poll OP, re-ordered and 2018 latest value added for context)

2003     5933760
2004     5683663
2006     5625046
2005     5179300
2009     5054055
2014     4884120
2018     4860720 [to date]
2013     4809288
2010     4622092
2008     4500623
2017     4472225
2011     4269199
2015     4257003
2007     4065739
2016     4017264
2012     3177455

18
Arctic sea ice / Re: What the Buoys are telling
« on: August 17, 2018, 08:35:48 AM »
There are no less than 3 ARGO floats north of Fram Strait which have been reporting data this month.

~5.7C at depth 20m near the NW corner of Svalbard (on Aug 4),
~2.8C at depth 200m further to the NE (on Aug 14)
and the furthest NE float (82.8N 22.1E) is showing a typical arctic water profile, peaking at ~1.8C at 200-300m depth (on Aug 14), with a healthy halocline above that.

19
Arctic sea ice / Re: What the Buoys are telling
« on: July 30, 2018, 05:13:20 AM »
The latest profile from the West Spitsbergen Current:

20
Permafrost / Re: Northern Hemisphere snow cover
« on: June 22, 2018, 01:17:09 AM »
It's the solstice. These three datasets (or 4, or 5) have different ideas about where there is still snow
(actually the last 3 somewhat agree - mainly looking at Victoria Island, Baffin Island and northern Quebec & Labrador).

None of the graphs had updated in 2-3 weeks, but now they're back! (except for FMI) - Snow water equivalent is back down to ~+1.5SD (another cliff in June). Extent now a bit more than that - ~+2.5SD.

21
Are you kidding? Have you taken a look at the in coming weather systems.
There are *always* incoming weather systems that people are talking about... Which sometimes eventuate and sometimes don't.

What baseline from previous years should we be comparing to in terms of incoming weather systems? In 2013, 2014, 2017, do we assume that the forecast at this stage in the season read "Weather for the next 10 days: nothing happens"?

22
Arctic sea ice / Re: Arctic Image of the Day
« on: May 22, 2018, 11:49:09 PM »
Apparently your forum software doesn’t handle orientation tags? The world is not actually upside down here.

And here I was being amazed at such a clear reflection of that cliff face in the water...

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