Latest PIOMAS Volume update

[SCYetti]

Posted by: ChasingIce
« on: August 06, 2014, 06:23:56 AM » Insert Quote
: SCYetti  August 06, 2014, 03:56:19 AM
The PIOMAS validation page states that their model has a bias that under estimates thick ice and over estimates thin ice. What is the effect of this when the Arctic ice is overwhelmingly thin.

apparently, it would over-estimate thin ice, and under-estimate thick(er) ice
Really? Well, duh!
Obviously I did not express myself adequately. I wanted quantification rather than verification. I should have asked " How great would be the effects of over-estimating thin ice would be.

[epiphyte]

So it is true that red is less thinning.

Now what did I write, hmm, grrm. I need a vacation.

..As do I - especially w.r.t my previous comment. I was interpreting the reduction in thinning at the edges as being due to an underestimate by the model... but duh... there was no ice in the first place!

(otoh - it might be a good idea to mask off the open water on that graphic, though...)

[Frivolousz21]

A lot of "thicker" ice according to piomas biting the dust in grand fashion.

Not saying piomas is crap.  But it seems to have over estimated some areas or what folks have been preaching to me on different websites about how August can't get the "big" melts is wrong. 

I have contended if the weather is right August can have huge melting.  We will see.

[epiphyte]

Friv writes:

I have contended if the weather is right August can have huge melting.  We will see.

I'm inclined to agree. Not least because once the ice is mobile, and once significant waves can form,  the weather can have all kinds of effects that have never heretofore been in play. There is a huge reservoir of energy in the water surrounding the arctic, and more only a few meters beneath the ice.

As I've said before I'm not predicting it will happen this year - if $100,000,000 worth of super-computers and the best brains in the business can't get the next week straight, I'm not about to try. But I do agree with Friv that that August is when it will be decided. Whether this year or another in the near future, I don't know.

[ChrisReynolds]

A lot of "thicker" ice according to piomas biting the dust in grand fashion.

Actually PIOMAS July figures show that virtually all the increase in volume is due to ice between 3 and 3.9m thick in the Central Arctic (70% of the increase in volume from July 2012 to July 2014). What PIOMAS does not show, unlike HYCOM, is a tongue of thicker multi year ice from Beaufort to the ESS.

[Wipneus]

Updated, graphs are in the top post.

(gridded data updated also, I will post the graphs later)

[Wipneus]

Here are the August 2013 /2014 thickness maps, as well as the differences.

[Wipneus]

An here is the August thickness change difference (2013/2014). Red means more thickening or less thinning than last year (which gives some headaches in areas that are open water in one year and ice covered in the other).

[iceman]

Thanks for the update.  Your last two graphics indicate that the relative y/y gain in thickness in the central area of the pack - a notable feature of this year's melt season, along with concentration in the same location - has mostly carried over from the previous month's PIOMAS data.
      Looking at the anomaly graphic on Arctische Pinguin, the recent uptrend is consistent with recent years, yet still a surprise to me.  I had thought the steep incline during July was something of a mid-season aberration, to be partly reversed.

[ChrisReynolds]

http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl

  At this time (2014/09/29), the NCEP/NCAR Reanalysis is not being updated at PSD as NCEP has halted their distribution. Any of our products or web-tools that use this data will be impacted. Data will be updated when it becomes available. We have no further information as to when that might be.

Will this impact PIOMAS?

If it persists it will certainly impact my blogging.

[viddaloo]

What's up, Chris? Are you saying there will be no PIOMAS October release? The US Govt is stopping it, effectively ending the 1979-2014 data series?

[ChrisReynolds]

I don't know, but PIOMAS is forced by NCEP/NCAR reanalysis data, no reanalysis data for September, no PIOMAS data for September.

Dr Zhang probably downloads as netcdf, I don't know if that is blocked too, but at present NCEP/NCAR reanalysis is suspended.

I do not know for how long.

EDIT - check out this Google search. Only one other person is asking what has happened and I've drawn a blank as to why.

[viddaloo]

Now, why would the Obama administration make such a dramatic move? Fire under his presidential behind?


This is probably why weather and climate should never be Weather.GOV or Climate.GOV.

[ChrisReynolds]

I've emailed Dr Zhang.

[ChrisReynolds]

Now, why would the Obama administration make such a dramatic move? Fire under his presidential behind?


This is probably why weather and climate should never be Weather.GOV or Climate.GOV.

OK I'll bite. There are plenty of mundane reasons why there might be a glitch in the reanalysis data update. So why start stooping to conspiracy theory nonsense? 

[viddaloo]

If one man decides to end a climate data service it's by definition not a conspiracy, hence no conspiracy theories are involved here.

[ChrisReynolds]

There has been a technical problem at NCEP. Dr Zhang confirms that the September PIOMAS data will be delayed until the issue is resolved and reanalysis data is available.

[viddaloo]

OK. Computer problem or real-life observation problem? And why don't they use the excellent communication medium that their website is to communicate this message?

[Neven]

Come on, don't exaggerate, viddaloo.

[viddaloo]

Come on, don't exaggerate, viddaloo.

We simply disagree, Neven, no big deal. I think the web can be used for communicating info, others don't think that can be done via a website.

[jdallen]

Come on, don't exaggerate, viddaloo.

We simply disagree, Neven, no big deal. I think the web can be used for communicating info, others don't think that can be done via a website.

Others, who are in the industry, and know the bureaucracy, understand just how glacial change in websites can be.   

Never ascribe to malice what can be explained by inefficiency or indifference.

[viddaloo]

Granted. Yet you must agree that 1) not displaying any notice on their website within a week, 2) not telling anyone online what sort of issue is allegedly haunting the NCEP, and 3) not being able to tell anyone online what day, month, year or decade the service will be back, if at all, or 4) whether it will ever be back, is a tad excentric.

Begs the question: Are we living in the Information Age or the Dark Ages?

[ChrisReynolds]

Viddaloo,

Stop wriggling. You're wrong.

You started off with a mindless conspiracy theory about the loss of data being due to the US administration wanting to hush things up, now you're making childish demands without having the foggiest what is going on.

If my house had been broken into and I couldn't fix the locks, the last thing I would do would be put up a sign announcing the fact.

You really are very, very tiresome. 

[viddaloo]

I think not telling anyone is excentric, you don't. This world would be a boring place if everyone on the planet thought it was excentric, or, on the other hand, if everyone on the planet thought it wasn't excentric, right?

In other words, we disagree on this one. It's not the end of the world.

Worse things happen at sea.

Calm down.

Breathe.

Good.

[OSweetMrMath]

The only "official" news I've found on this is at the ESRL PSD site (http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html) which has been updated today to say "As of 2014/10/03, the NCEP/NCAR Reanalysis 1 is being updated at PSD. Some products are catching up and we don't yet know when normal distribution will return at NCEP." Hopefully this means that this was a temporary problem and PIOMAS will be updated soon.

Before I found that, I went to the NCEP/NCAR Reanalysis Wikipedia page (http://en.wikipedia.org/wiki/NCEP/NCAR_Reanalysis), which generally needs help, but it was revised about a day ago to read that the updates stopped in September 2014.

The update was made anonymously and does not have a citation. Does anyone here know anything about the Wikipedia change? In any event, based on the update at PSD, the change on the Wikipedia page does not appear to be correct.

[viddaloo]

Seems strange to criticise someone who's asking what sort of technical issue it is, for not knowing enough about the sort of technical issue involved. Rather than calling that "making childish demands", one could view it as a method of getting to know what sort of technical issue we're talking about. Had you known more about the type of issue, Chris, you probably would just say so.

Asking someone who might know is a great way of getting to know more. I know a lot of people disagree with me on this one. But people are different, and that's a good thing.

[ChrisReynolds]

Seems strange to criticise someone who's asking what sort of technical issue it is, for not knowing enough about the sort of technical issue involved. Rather than calling that "making childish demands", one could view it as a method of getting to know what sort of technical issue we're talking about. Had you known more about the type of issue, Chris, you probably would just say so.

Asking someone who might know is a great way of getting to know more. I know a lot of people disagree with me on this one. But people are different, and that's a good thing.

If I am told something in a private conversation, and if I suspect it might be information that one probably shouldn't make public, would it not be dishonourable for me to say such a thing publicly?

The reason I said it publicly here is because I noticed that on another thread (effective thickness) you alluded to such a reason - so I presumed the matter was now in the public domain.

[ChrisReynolds]

New announcement:

As of 2014/10/03, the NCEP/NCAR Reanalysis 1 is being updated at PSD. Some products are catching up and we don't yet know when normal distribution will return at NCEP.

http://www.esrl.noaa.gov/psd/data/composites/day/

[viddaloo]

Just taking a wild/educated guess based on the excessive secrecy of this matter. Let's hope it all comes up again nicely and that no data are lost.

[ChrisReynolds]

I doubt if data will be lost, looks like there's a chance of having PIOMAS data by the end of the week (if they're already putting things right at NCEP/NCAR).

[Neven]

Humans are involved, that's all I need to now. And as I'm human myself, I try not to interpret or judge too much. 

[ChrisReynolds]

Not long to wait now folks.

Then we can see how much 'baggage' the sea ice will carry into winter 2014/15. 

[viddaloo]

Great, Chris!

PS: Is anything official yet about the outage?

[ChrisReynolds]

Great, Chris!

PS: Is anything official yet about the outage?

Nope. Dr Zhang has said it is just what he heard and may be wrong. Another scientist told me the same thing, but that doesn't mean anything if it is a rumour in the community.

Anyway. I'm winding down for the evening. So if the data is released tonight (later afternoon in the US), I'll have to leave doing something about it until tomorrow night.

[diablobanquisa]

[slow wing]

So, eye-balling, it looks like just a jot under 7000 km^3 at minimum?

[viddaloo]

Hard to tell. Latest PIOMAS daily download still terminates on August 31st.

[slow wing]

So that isn't September's data in the plot just above posted by diablobanquisa?

[viddaloo]

Yes, it is. But as I just said, they haven't released daily numbers post-August yet.

[ChrisReynolds]

Gridded updated. Crunching numbers while I eat dinner. 

[ChrisReynolds]

Too tired to blog tonight, but here's PIOMAS volume for September for the regions of the Central Arctic.

The regional PIOMAS numbers have been updated, apart from the daily volume (HiDay has not been updated since August).
http://dosbat.blogspot.co.uk/2013/12/regional-piomas-volume-data.html

[viddaloo]

I'll think of something. Adding up the regions, for instance. Then we can have volume data even for September 2014, despite the #%^* incidence.

[slow wing]

Cheers for all your work, Chris. Much appreciated... 

[ChrisReynolds]

I'll think of something. Adding up the regions, for instance. Then we can have volume data even for September 2014, despite the #%^* incidence.

By gridded monthly data - haven't checked this morning if the main series is updated, just turned on my laptop to put more tunes on my MP3 player.

Total Volume.
6972.35 km^3

Central Arctic Volume.
6330.35 km^3

Slow Wing, Thanks, I'm glad it's of use to you.

[viddaloo]

I'll say thanks, too, Chris.

Checked PIOMAS volume again several times the last hour. Still very secretive about this year's September

[viddaloo]

1400 CET: Last daily volume is for August 31st.

[iceman]

Cheers for all your work, Chris. Much appreciated... 

Likewise... looking forward to your post on Dosbat.

[Wipneus]

I asked Dr Schweiger who fixed the issue immediately.

So data is updated, the usual monthly graphs are in the top post.

I will post the graphs based on September minimum later, the curve fitting algorithms are experiencing difficulties  :-(

Gridded data updated also, I will post those graphs first.

[viddaloo]

September 2014 daily sea ice volume:

2014 244   7.187
2014 245   7.164
2014 246   7.131
2014 247   7.110
2014 248   7.084
2014 249   7.067
2014 250   7.044
2014 251   7.009
2014 252   6.985
2014 253   6.963
2014 254   6.932
2014 255   6.902
2014 256   6.869
2014 257   6.834
2014 258   6.840
2014 259   6.834
2014 260   6.821
2014 261   6.810
2014 262   6.818
2014 263   6.839
2014 264   6.870
2014 265   6.892
2014 266   6.900
2014 267   6.937
2014 268   6.980
2014 269   7.015
2014 270   7.056
2014 271   7.077
2014 272   7.099
2014 273   7.119

PS: Note that for the first time since 2009 there is a net volume loss in September.

[Wipneus]

Here are the September 2013 /2014 thickness maps, as well as the differences.

EDIT: the difference graphics showed the wrong month.