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Messages - SimonF92

Pages: [1] 2 3
1
Developers Corner / Re: Test space
« on: February 08, 2021, 04:38:17 PM »
<add an if statement>
At the moment I delete entries >0.99m/s but I think it's interesting to see the deployment, also some resupply vessels to mosaic and other expeditions. I was thinking the opposite so that all deployment journeys were visible but more accurate, rather than taking short cuts across land ;) . We'll see what's cleanest. I think the problems might be in the way I'm loading the data using rbind.fill. Plus I didn't really check much when I started using the daily full resolution data. I've been lazy just running the existing code in the background.
Busy looking at ess leads today.

here's 2017-2021, crf31 compression is getting higher to reduce 266MB down to 11MB, 3hrly so I can overlay nullschool at some point. Daily didn't really work for me.
2014-2021 is going to be a big file though...

2
Developers Corner / Graphtoy
« on: January 04, 2021, 12:46:25 AM »

3
Arctic sea ice / Re: What the Buoys are telling
« on: January 02, 2021, 08:52:38 PM »
IABP buoys 2012-2014.

4
Arctic sea ice / Re: What the Buoys are telling
« on: December 22, 2020, 05:54:58 PM »

//////////////// PS, would welcome criticism of my Arctic-donut approach to defining region (will also be bugged before 1986):

lon=(df.Lon.values.tolist())
lat=(df.Lat.values.tolist())
locations=[]
for lon_i,lat_i in zip(lon,lat):
    if lat_i > 80:
        location='Central Arctic Basin'
    else:
        if lon_i > -161 and lon_i < -125:
            location= 'Beaufort'
        elif lon_i > 148 and lon_i < 178:
            location= 'ESS'
        elif lon_i > 95 and lon_i < 148:
            location= 'Laptev'
        elif lon_i > 56 and lon_i < 95:
            location= 'Kara'
        elif lon_i > 16 and lon_i < 56:
            location= 'Barents'
        elif lon_i > -15 and lon_i < 16:
            location= 'Greenland'
        else:
            location= 'Chukchi'     
    locations.append(location)   
df['location']= locations
A couple of suggestions to align a bit closer to wipneus and nsidc. I think 80N is a good compromise.
if lon_i > -157 and lon_i < -125:     ## utqiagvic as marker
            location= 'Beaufort'
        elif lon_i > 145.5 and lon_i < 178:
            location= 'ESS'
        elif lon_i > 97 and lon_i < 145.5:  ##mid NSI
            location= 'Laptev'
        elif lon_i > 64 and lon_i < 97:
            location= 'North Kara'  ##not many buoys in Kara anyway?
        elif lon_i > 16 and lon_i < 64:
            location= 'Barents'
        elif lon_i > -45 and lon_i < 16:  ##coastal drift might be interesting
            location= 'Greenland'
        else:                   ## 157 to 178 though this will include bering, cutoff at 66.5N?
            location= 'Chukchi' ##probably best to define chukchi or it may pick up CAA/baffin outliers

5
Very interesting, had no idea about "flushing"
Could be that many of our assumptions about ice melting and refreeze need confirming.
Quote
For the time being, instead of having a set value of -1.8 I just set ice bottom as the thermistor below which the temp is 0.2degC less than whatever the ocean temp is at that measurement time.
''
ice_thermistors=ice_or_water_thermistors.where(ice_or_water_thermistors<mean_ocean_heat-0.2)
''
Looks good if my ice temperature doubts turn out to be wrong.

17 older tbuoys deployment report update

6
Arctic sea ice / Re: MOSAiC news
« on: November 24, 2020, 12:18:53 AM »
I know this is a scientific discussion and I have no science to add so I'll be brief, but A-Team those "plot Z-stack profile" images, particularly the laptev wedge one, are worthy of display in a gallery somewhere.

An absolutely brilliant visualisation. Like a thinning forest of leaves. It brings the data to life!

7
Arctic sea ice / Re: MOSAiC news
« on: November 23, 2020, 02:28:58 PM »
Here is some additional analysis of the Laptev region. The first figure shows an all-in-one analysis of open water for the first 65 days past the Sep 15th minimum for 11 years back to 2010, the second looks at growth of ice to a half meter or more in Smos-Smap which has been very slow in 2020 with much of the Laptev still only 20-30 cm thick on Nov 23rd.

The third figure looks at ice less than one meter thick during late winter of 2020, with some still present at the start of melt season.
\
The final figure removes the very highest concentrations of ice in AMSR2_AWI  on 21 Nov 2020 to let the ice thickness below from Smos-Smap show through. Note that the tan color at lower right is likely a weather artifact in AMSR2; indeed selecting this color in Smos_Smap is a way of removing it.

8
The rest / Re: What is your likeability?
« on: November 05, 2020, 06:49:42 AM »
worth  a reply i guess.
I have a high like ratio on this blog.
About .5
In the real world my views are  marginalized and I find it hard to relate to the "normal" person I encounter.
Because.
First and foremost I have what they call Asperger syndrome this simply means  I dont think like "normal" person. I/100 ...
2nd is IQ apparently mine is something like 2 sd to the right . another 1/100....
On this forum both of my differences are approaching normal hence what I have to say often resonates  with  the average person on here.
What does  my high like ratio mean to me ?
It makes me feel I am among my peers and a valued contributor with views worth considering rather than feeling alone in an incomprehensible uncomprehending world .

9
Arctic sea ice / Re: The 2020/2021 freezing season
« on: November 01, 2020, 11:32:15 AM »
IABP buoys sea temperature, oct18-31
data attached as text. (760 is off map in the Kara) 761 data fits with yesterday's coastal refreeze shown on amsr2.

10
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 26, 2020, 11:22:43 AM »
NSIDC comparison tool.  Oct 24 2020 ice extent vs Oct 24 2019, 2016, 2012.

11
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 25, 2020, 02:50:27 PM »
IABP buoy drift and surface temperature update.(11MB)

closer look at iabp204761 and 204762 in the Laptev (3.5MB)
click

12
Developers Corner / Re: Test space
« on: October 05, 2020, 09:49:40 PM »
buoys, april-oct. Ignore the deployment straight lines.

13
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 02, 2020, 02:20:08 PM »
The first SMOS thin ice thickness map of this freezing season is released.


14
Arctic sea ice / Re: The 2020/2021 freezing season
« on: October 01, 2020, 12:37:46 PM »
Here's the sea ice concentration animation for all of September. The dynamical movements are pretty interesting to watch.
There'll be a larger, better quality version going up on my twitter page in about 2.5 hours

(Large animation, ~11mb. Click to Play)

15
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 29, 2020, 01:42:21 PM »
And the latest images and animation.

BFTV, the last frame in the final figure (the gif), shows the total change over the period- that is itself a nice visualisation and could be a stand-alone

Here ya go

16
Arctic sea ice / Re: The 2020/2021 freezing season
« on: September 29, 2020, 10:56:55 AM »
And the latest images and animation.

17
Arctic sea ice / Re: The 2020 melting season
« on: September 28, 2020, 09:44:17 PM »
2020, 2018, 2015, 2012, and 2009. Roughly the same days, similar location.

18
Arctic sea ice / Re: The 2020 melting season
« on: September 06, 2020, 10:16:26 PM »
Snow will indeed increase (marginally) but eventually this will transition to rainfall
Amazing graphic, may I ask where it is from?
https://www.nature.com/articles/s41598-018-34450-3

19
Arctic sea ice / Re: MOSAiC news
« on: September 04, 2020, 09:02:21 AM »
Before it gets too far back, just want to say thanks very much for your detailed & very informative replies to my question on finding the ice bottom from the thermistor strings, SimonF92 and uniquorn.

I'm still digesting your replies & my understanding of the physical situation - things like the fresh water lens - definitely needs some revisions.

20
Arctic sea ice / Re: The 2020 melting season
« on: August 25, 2020, 02:33:50 PM »

Scary that over 70% of the ice is just 10cm-30cm thickness

10cm - 3.93 inch
20cm - 7.87 inch
30cm - 11.8 inch

As had been written countless times, that chart, during summer does not mean that. Please read comments upthread

21
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: August 25, 2020, 11:42:44 AM »
This is one thread where I will really miss blumenkraft's contribution to the forum . Big block is hanging around for his hoped for return .. b.c.

22
Arctic sea ice / Re: The 2020 melting season
« on: August 23, 2020, 12:42:31 PM »
I think that the fact that 2020 seems to be coming in second is almost as scary as if it were heading for a record. 2012 was a freak, but each normal year is getting lower and eventually we will pass 2012, even if there is not another cyclone or something.

24
Arctic sea ice / Re: The 2020 melting season
« on: August 10, 2020, 11:35:15 AM »
Below is the change in concentration from the 8th to the 9th of August. The second is the absolute change, where sea ice was lost or gained for the same dates.

25
Greenland and Arctic Circle / Re: St. Patricks Bay Ice-caps are gone
« on: August 07, 2020, 09:11:40 PM »
While looking for these I set one image to last year and one year to now. I was shocked by how many ice caps lost significant volume in the last year.  :o

26
Greenland and Arctic Circle / Re: St. Patricks Bay Ice-caps are gone
« on: August 07, 2020, 07:14:38 PM »
I remember reading about these in 2017 and hoping they might be making a cyclical recovery, but no, they are officially gone

https://nsidc.org/news/newsroom/st-patrick-bay-ice-caps-canada-have-completely-disappeared

There are are many spots in Greenland were the situation is similar, just opposite Ellesmeere Island in Washington Land and next to Petermann at least a dozen are gone or almost gone.

27
Arctic sea ice / Re: The 2020 melting season
« on: June 26, 2020, 01:27:11 AM »
Why post month old Hycom?
Sorry. Because of the garlic press discussion.

28
Arctic sea ice / Re: The 2020 melting season
« on: June 26, 2020, 01:16:01 AM »
That HYCOM model ^^ predicts lift off of the thickest ice , which may soon come slamming back and have us an active garlic press by the middle of July . Just one of the many reasons this could still be BOE No 1 ! b.c.
This model has been showing an active garlic press, or perhaps cheese grater or ice cream scoop since may.
Whether Its right or not, blue has gone deep violet on worldview in the most protected place for seaice in the arctic today.

29
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: June 22, 2020, 02:26:41 PM »
It's getting a bit tricky to discern open water and shadows with all that cloud at the moment.

DMI is showing new opening just above Alert in the Lincoln Sea.

Yes, that opening has been visible from the station, it's only a couple hundred metres offshore from us.  We had very high winds (sustained 15-20 m/s) from Thursday through Sunday that did a lot of melting and pushing.  The majority of our snow cover disappeared in that period.

30

If one were to zoom in with a powerful enough microscope, they would see that the ice and the brine are discrete entities.

In liquid state, sea water is H2O molecules bound by hydrogen bonds (intermolecular bonds) with salt ions (Na+ and Cl-) dissolved in solution.

During the freezing process, the salt ions and some of the H2O molecules are separated from the rest of the H2O molecules. The crystal lattice of ice is composed of only H2O molecules bound together by intermolecular bonds. Consider this lattice to be similar to a house which is held together with wood and screws.

The brine exists in the spaces within the lattice, but is not part of the lattice itself. The brine is like a sofa inside a house. It fits inside the house, but it is not a component of the ice house and does not impact the strength (heat) required to dismantle the ice house.

As you indicate, the brine does exit the ice lattice over time... by escaping through the spaces in the lattice. Most of the brine exits within a year of ice formation.

The lattice portion of the ice house is the same in the Arctic as the ice in your freezer and melts at the same temperature.

As one who in my chemistry career used salt-ice baths to achieve lower than 0ºC temperatures I wish to correct the physical chemistry referred to in this post.

When water freezes into ice, the hydrogen bonds make a hexagonally shaped network of molecules inherent to the structure of ice.
When a solute is added to water the ordering of the solvent molecules is disrupted. This means that more energy must be removed from the solution in order to freeze it.
When salt is added to water, the resulting ions in the water disrupt the usual network of hydrogen bonds made upon freezing. As a result, the freezing point of the solution is lower than it is for the pure solvent. This is termed freezing point depression.  As the ice warms up the network of hydrogen bonds (referred to above as the lattice) requires less energy to be broken up so the melting point is lower.
Because the solubility of the salt decreases with temperature some of the salt is rejected, forming brine pockets.  These brine pockets get eliminated over time but some salt remains in the ice disrupting the structure. In multiyear ice the salt content will ultimately reach the solubility of the lowest temperature the ice has reached so in thick MYI you'd expect lower salinity at the top vs. the bottom.

Here's an amusing video illustrating the difference in melting between saline and pure water ice.


32
Good luck :) as long as you don't block adblockers.
Continuing analysis of T77 here are the temperatures from may18-jun2. I think there was snow between therm39 (possible therm37) and 43 and based on the animation above, I don't think there is bottom melt yet.
Not sure which parameters can be adjusted to match.
click for a gif to get rid of the lines.

33
Arctic sea ice / Re: 2020 Melting Season Predictions
« on: May 31, 2020, 10:21:29 PM »
Interesting figure (couldnt find source article unfortunately)

This is the original source i think, Simon >> https://sites.google.com/site/arctischepinguin/home/piomas/

34
Arctic sea ice / Re: 2020 Melting Season Predictions
« on: May 31, 2020, 10:16:31 PM »
This picture has been presented in this forum before.
It is based on the projections made in 2012 where an ever faster decrease was assumed.
But then came the increases in 2013 and 2014.
Therefore this picture is just an illustration of what could have happened if the disastrous 2012 melting season would have had even worse follow-ups in the next years.

35
Consequences / Re: Temperature signals from Covid-19
« on: May 27, 2020, 03:16:02 PM »
Come on guys the CO2 impact from COVID-19 & the impact on global temperatures is so minuscule it's noise at best.  The fact that you think will be able to track it month-by-month global mean temps affects is silly.

You realize that CO2 concentration growth year-over-year is responsible for an additional radiative forcing of like ~0.03 W/M².  Estimates have 2020 *annual* emissions down 7%.  That's doesn't even account for all anthropogenic CO2: land use changes, etc..  Regardless, that 7% drop in emissions due to COVID-19 is a drop in radiative forcing of  ~0.00021 W/M².

Also what's the obsession with satellite data?  Surface temperature data is way more accurate for global mean estimates.  You realize that satellite data goes through massive algorithms & corrections because of changes in orbits & time of day passes.

The focus should be on aerosols not CO2 concentration changes when talking about COVID-19.

36
The port at 8501 is unfortunately a must, and wont be going away any time soon

http://www.mosaic-ice.com:8501/

"Any port in a storm."

37
I think the 'fortress' ~1km distance from PS may be over 6m thick. I can't find the reference though.
Quote
On 28 September the first researchers from Polarstern set foot on the floe, which had long been a preferred candidate thanks to the promising analyses of the satellite data. On the radar images produced by the satellites, the dark, nearly oval floe stood out thanks to a large, bright region in its northern section. This clearly set it apart from all of the other potential floes, which were consistently dark in the radar images. In the meantime, the experts have dubbed this region ‘the fortress’: made up of highly compressed, several-meter-thick ice,
webapp is a good idea but probably won't run directly from the forum

39
The 2 remaining cryosphereinnovation simb buoys are in broad agreement with our numbers. Snow depth perhaps more stable.
piomas indicating our results should be a touch thicker

40
Will look at that in a bit. First draft of the ani. My initial impression is that it's a shame to lose the path detail by using only 1frame/day. How about we use all the ts data but replicate the thicknesses.
Note that none of the buoys are over 2m thick using this method.  ctr
I have a feeling they are all going to experience sudden melt at this drift rate.

adjusted a few things ctffr
and added est snow thickness, though I can't do 2 colours at a time.

41
Policy and solutions / Re: Lessons from COVID-19
« on: March 31, 2020, 05:34:01 PM »

The system requires, no, demands more consumers, and growing consumption rates. Why is that?

Because it was put in place after WW2 to give US industries, which had boomed during the war, somewhere to push their goods to.  To ensure that the end of the war did not wind up with an inevitable depression.

It was sound at the time but nobody expected that the whole wold would become invested in a short term "fix" solution.

It continues to exist today and shouting "the king has no clothes", whilst ignoring why it has continued in the way it has and also all angles of the situation, is more likely to get the little boy stoned than for the people to suddenly wake up and realise the situation is unsustainable.

42
Arctic sea ice / Re: The 2020 melting season
« on: March 29, 2020, 08:42:49 PM »
nothing out of the ordinary
One thing that is different, or that I haven't seen before, is the large leads that have developed since feb15 making their way around north greenland so early in the season. With >80km/h winds forecast on apr1 we are likely to see them open up more.
Kaleschke SIC leads, oct1-mar29

43
Estimated thermistor numbers based on last entry in heat120 files (chart attached, cffr)
buoy   Th(snow)   Th(ice)
T56   24   35
T58   18   34
T62   40   51
T63   18   32
T64   24   47
T65   12   35
T66   42   49
T68   34   46
T70   32   42
T72   28   36

T69   25   35


44
Looking only at T64 where the chart shows 3 clear drops in estimated thickness. The temperature ani doesn't show any bottom melt events. There are, however, some higher air temperatures that flatten the curve that may occur at roughly the same time as the 3drops.
Not exactly a bug but perhaps an error in the method.
Some thermistors are recording persistently higher temperatures. Perhaps there was a problem during calibration
Was using Spyder but jupyter charts are good


Still need to see a time series of the stdev(10rows) charts to see it they are messing about during temperature rises

45
T56 method comparison
eyeballing the numbers Therm-snow/ice=30 for the spreadsheet method
Spreadsheet method is less complicated, std dev+ is more mathematically justifiable
Is the difference down to snow depth?

Quote
Nag to the 17: This is probably a once in a decade opportunity to use the mosaic project to gather almost unprecedented near real time arctic data. Perhaps you are content to sit back and watch a model. Maybe a view from a satellite. Maybe just wait for someone else to do it. But why? There are over 70 active buoys in the arctic today(Mar18). Why aren't we analysing them?? If we are. Why aren't we sharing??

46
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 31, 2020, 10:39:56 PM »
Here I have plotted the normalized average extents in january, februrary and march, compared to september. Normalized meaning the value divided by the average value for the whole year. This means that the long-term trend of general melting is removed.

There seems to indeed be a strong correlation of high extent early season = low extent late season, for all three months graphed.






47
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 14, 2020, 03:53:40 PM »
Average surface wind anomalies during the past 12 months: (source)
Thanks Steven. Here comparing noaa/esrl sep-dec wind anomaly with jan1 uni-hamburg amsr2, 2013-2020. click to run.

48
Arctic sea ice / Re: The 2019/2020 freezing season
« on: December 20, 2019, 12:28:41 PM »
Thanks johnm33, I hadn't seen these before.

https://www.uaf.edu/cfos/research/institute-of-marine-scien/zygmunt-kowalik-publicati/Kowalik-Tides.pdf
Quote
The  largest  component  of  the  tide  in  the  Arctic  Ocean  is  the  semidiurnal  M2 (period  12.42h).  Since  the  tide  producing force for this constituent in the Arctic Ocean is very  small,  the  origin  of  this  wave  is  an  incoming  tide  from  the  Atlantic  Ocean.  The  M2  tide  entering  the  Arctic  Ocean  between  Greenland  and  Scandinavia  is  divided  by  Spitsbergen into two branches. The main wave enters through the Greenland Sea and the secondary wave propagates around Scandinavia  towards  the  White  Sea.  The  latter      has  amplitude at Northern Norway of about 1m. In the White Sea at the entrance  it grows to  about 2-3m and in the shallow Mezen Bay the amplitude is greater than 4m.   The  M2 wave  in  the  main  basin    of  the  Arctic  Ocean  propagates  during  one  period,  counterclockwise  around  an  amphidromic point located off the Canadian Archipelago. The tidal  amplitude  is  zero  at  an  amphidromic  point,  and  it  increases    towards  the  shoreline.  While  traveling  in  the Arctic Ocean the M2 wave undergoes transformation. When it impinges  on  the  North  Siberian  Shelf  its  amplitude  diminishes  through  the  bottom  friction.  Along  the  North  Siberian  Shelf  the  amplitude  is  about  20-30cm  and  further  the amplitude decreases to 5-10cm at the Alaskan shore. The M2   tidal currents in the deep basin are quite small of the order of 2cm/s. The strong currents were observed along the coasts in the shallow water of the Barents Sea, especially over  Spitsbergenbanken  and    close  to  the  Bear  Island.  The  strongest  currents  often  up  to  2m/s  occur  at  the  entrance    to  the  White  Sea.  Along  the    North  Siberian  Shelf, 
especially  in  the  region  of  the  New  Siberian  Islands,  the  M2   tide  currents  are  often  of  the  order  of  50  cm/s.  The  variability of the tidal currents is much stronger compared to  the  tidal  levels,  because  currents  depend  on  the  local  conditions, e.g., the currents along Alaska Beaufort coast are  of  the  order  of  5-10cm/s,  but  in  the  narrow  entrances  to the coastal lagoons they  can be enhanced several times. Amplitudes of the second semidiurnal constituent S2 (period 12h)  are  much  smaller  but  the  general  picture  of  the  wave  propagating  counterclockwise  in  the  main  basin  is  very  similar to the M2 wave. 
https://www.researchgate.net/figure/The-schematic-pattern-of-the-model-M-2-energy-flux-in-the-Arctic-Ocean-and-adjacent_fig5_44021887

49
Arctic sea ice / Re: The 2019/2020 freezing season
« on: December 19, 2019, 07:05:54 PM »
Wat?

50
Arctic sea ice / Re: "Smart" and "Stupid" Questions - Feel Free To Ask
« on: November 26, 2019, 10:01:33 PM »
Irrespective of ecological effects, based purely on geophysics, would a wall here help to preserve Arctic ice?

If you fancy a VERY LONG read, you can start here...

https://forum.arctic-sea-ice.net/index.php/topic,1545.msg76945.html#msg76945

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