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Messages - uniquorn

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101
Arctic sea ice / Re: MOSAiC news
« on: September 19, 2020, 04:22:04 PM »
The default scale is utm km which may be reasonably accurate this close to the pole, though confusing to some, so I normally remove it. Recent location of most of the nearest buoys to PS

102
Arctic sea ice / Re: MOSAiC news
« on: September 19, 2020, 03:35:13 PM »
drift update from P176.
2 submarine landslides a day seems unlikely. I think I'll stick with tides.

103
Arctic sea ice / Re: The 2020 melting season
« on: September 18, 2020, 01:09:19 AM »
I see it differently, I think both years were eventually quite similar, when using generalizations:
2012 was sunny and warm and then windy and very stormy. It had some extra fluffy ice in the ESS but eventually it melted that ice and was left with a compact pack (and an extent record).
2020 too was sunny and warm and then very windy and somewhat stormy. It had some extra fluffy ice in the Chukchi and Siberian facing sections of CAB,  but eventually most of it melted and it was left with a mostly compact pack - except in the CA and the Beaufort arm (and a 2nd place extent finish).
I agree, only to stress that 2012 was an outlier and 2020 is almost normal as the global warming goes on.
Also I don’t see a paradigm shift at all, just a continuation of a warmer planet due to CO2. The ice is basically the same, only a lot less.
I agree too and would add that, with less ice, the arctic ocean is beginning to show itself more. Last year the CAA crack and this year the Greenland gap.

104
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 17, 2020, 05:09:01 PM »
Signs of turbulence north east end of the yermak plateau. https://go.nasa.gov/3iLPHNq

105
Arctic sea ice / Re: The 2020 melting season
« on: September 17, 2020, 01:01:16 PM »
AMSR2: Some recent days of 2020 compared to 2012
Rough overlay of 2012 vs 2020 using awi amsr2 v103, aug20-sep15 (am/pm)

gimp grain extract, the years were slightly different sizes so there is a small scaling error

106
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 17, 2020, 12:42:07 PM »
I wonder if awi amsr2 sic v103 is using some of the SIC LEADS (experimental) processing.
Yesterdays worldview terra modis with v103 inset.

107
Developers Corner / Re: Test space
« on: September 17, 2020, 12:42:43 AM »
grain extract was better. Might try more accurate scaling tomorrow.
posted elsewhere

108
Developers Corner / Re: Test space
« on: September 17, 2020, 12:28:09 AM »
tried to do difference on seaice.de post here
Strange that the two years were different pixel sizes. A very rough resize produced this, so I think I've done something wrong. Interesting though.
removed

109
Arctic sea ice / Re: The 2020 melting season
« on: September 16, 2020, 11:12:06 PM »
Wipneus' regional extent chart for the CAB suggests there has been a physical limit for latest refreeze set by 2012. 2018 and 2019 tending to confirm that limit. 2020 is close to testing it.

110
Arctic sea ice / Re: MOSAiC news
« on: September 16, 2020, 10:05:08 PM »
A lot of good videos on https://twitter.com/seaice_de

Quote
The Polarstern is represented by the gray ball; it is moored with its starboard bow against the ice
Quote
Lars Kaleschke@seaice_de
12 Sep  Too much tension? Be careful with the anchor line. A very dangerous environment. @MOSAiCArctic  - April 28



111
example of ice/ocean interface

112
Arctic sea ice / Re: MOSAiC news
« on: September 16, 2020, 09:36:21 PM »
Probably best with VR headset but you can use the mouse (or finger) to look around. Look up first to  lose the auditorium.


113
latest t78 and t81. T78 is an algo nightmare

114
Arctic sea ice / Re: The 2020 melting season
« on: September 15, 2020, 11:32:08 PM »
relative "compactness" of the ice pack compared to say 2016
Laptev/atl ice edge has been subjected to a few weeks of southerly wind so yes, relatively compact compared to 2016 and at the same time a short cyclone leaves the pack riddled with leads north of CAA while the Greenland gap slowly recovers (a large polynya is visible today at 85.2N-10)
https://go.nasa.gov/2Rycjog  (light contrast enhancement)

115
Arctic sea ice / Re: MOSAiC news
« on: September 15, 2020, 09:32:47 PM »
That 25km2 of bow radar might overlay nicely onto buoy drift now that it is relatively static. A shame it's not hourly.
This is a wider view of the previous animation here with the tight cluster at the centre.

intermittent light snow


  Lat  Long  YY-MM-DD  UTC     Wind       T(C)  N  h  VV  wwWW  ICE  Pnn(hPa)
  89.1  108.3 20-09-15 20:00    4  230     -4.6  /  /  //  //// ///// 1005.2
  89.1  108.1 20-09-15 19:00    5  210     -4.9  /  /  //  //// ///// 1005.2
  89.1  107.9 20-09-15 18:00    5  200     -4.7  /  /  //  //// ///// 1004.9
  89.1  107.6 20-09-15 17:00    4  220     -4.7  /  /  //  //// ///// 1004.8
  89.1  107.3 20-09-15 16:00    4  230     -4.9  /  /  //  //// ///// 1004.8
  89.1  107.1 20-09-15 15:00    4  200     -4.9  8  2  98  7082 49/9/ 1004.7

116
They were probably just spam on the mosaic thread.
@SimonF92 is it possible to take surface temperature into account when using the heat files in the algo?So that it amplifies the stdev in some way.

117
Arctic sea ice / Re: MOSAiC news
« on: September 15, 2020, 07:54:21 PM »
drift speed increased during sep13-14. click for motion

118
t78 and t81 temp proc

119
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 14, 2020, 09:20:26 PM »
Last four years.
You have a reasonable point that the ice age product shows a possible increase in 4+ year ice.
A technical graphics question. What made you choose to insert a transition that ignores the other 51 weeks into that animation? It makes no sense (and increases the file size).

120
Arctic sea ice / Re: MOSAiC news
« on: September 14, 2020, 03:46:39 PM »
Quote
Somewhere up-forum, all the weather commentaries for the entire expedition was extracted into a flatfile database and a MS Word-type glossary system proposed to stub in the code lookups to eliminate tedious and error-prone code lookups. No one picked up that baton.

63 downloads, quite popular. Though no further analysis from them.
Looking at some thread stats is valid as we near the end of the mosaic project. Gauging popularity of areas of analysis can be useful to determine viewer interest and whether sizing an animation to fit the forum's tight limits is worth the effort

Thanks, I hadn't  heard of diamond dust or graupel before.

121
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: September 14, 2020, 01:24:20 PM »
nsidc ice age for the week to sep1 (or sep2), 1984-2020

122
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 14, 2020, 01:01:35 PM »
Quote
It might make sense to make an avi using each consecutive pass as a frame.
That might be a more efficient than the am/pm. A daily avi of swaths which could be compiled by the user, one daily tiff compiled with lut, one compiled png and one compiled .nc
Avi might not be the best option. I think a tiff can contain multiple 'pages' which might retain the lut.

123
t78 and t81 heat120 temps
t78 has some odd features

124
Arctic sea ice / Re: MOSAiC news
« on: September 14, 2020, 11:33:22 AM »
Sorry about that. I mixed up the ww and the WW
I should have said snow or mixed rain and snow moving to with less significant rain
Quote
W1 -- Most significant weather in past 6 hours
W2 -- Less significant weather in past 6 hours

    0 -- cloud covering less than half of sky
    1 -- cloud covering more than half of sky during part of period and more than half during part of period
    2 -- cloud covering more than half of sky
    3 -- sandstorm, duststorm or blowing snow
    4 -- fog, or thick haze
    5 -- drizzle
    6 -- rain
    7 -- snow or mixed rain and snow
    8 -- showers
    9 -- thunderstorms
Quote
76 -- diamond dust

Recent weather is hovering around 0C with continuous light drizzle.

125
Arctic sea ice / Re: MOSAiC news
« on: September 13, 2020, 10:54:08 PM »
Sub -12 C now:

  88.7  105.8 20-09-10 22:00      -12.4 
  88.7  106.0 20-09-10 21:00      -12.1 
  88.7  106.1 20-09-10 20:00      -12.6 
 

And then back to above 0C with freezing rain and 'diamond dust'

126
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 13, 2020, 10:29:48 PM »
nsidc ice age update

127
Arctic sea ice / Re: Tides
« on: September 13, 2020, 04:04:08 PM »
Some buoys near the pole

128
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 12, 2020, 11:25:50 PM »
Quote
We are looking on this forum for an explanation of what visible, infrared and radar satellite imagery and drifting buoys have been showing for months above Greenland, Ellesmere and CAA which are nowhere near major rivers or their plumes yet the ice has been melted out to the point of oblivion by insolation and MDD this summer. We have direct confirmation from the captain of the transiting Polarstern.
Hopefully not too far off topic, this long term view of mercator 34m salinity could provide an explanation. There is a noticeable acceleration during the 2020 strong tpd event pushing higher salinity atl water? towards the greenland coast.
sep2018-sep2020

129
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 12, 2020, 10:57:14 PM »
mercator 34m salinity, jun1-sep11
Mercator not showing anything unusual north of greenland at 34m (short term)

130
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 12, 2020, 10:04:20 PM »
yes, I used to get told off for posting animations without the scale but including it in the animation makes the file size larger so I post it separately, if I remember. hmm

131
Arctic sea ice / Re: MOSAiC news
« on: September 12, 2020, 10:01:12 PM »
Quote
My sense is that buoy data needs a lot more edu: arrows drawn on stills, longer prose accounts of basics, fewer assumptions that such and such is obvious, tutorials even
You're probably right. Arrows on things no one looks at. Post some buoy data once a month.

132
Arctic sea ice / Re: MOSAiC news
« on: September 12, 2020, 09:38:10 PM »
The drone photo is both beautiful and shocking because of the blue water in the ponds apparently on 6 September. Because the basic info identifying the photo has been stripped, I'm left wondering if it was actually taken in the month of September at the pole.
Air temperature was mostly below 0C at PS location for a week before sep6. The pond water would have to be quite fresh saline.

aug25 was first full day on the floe according to fomo. Pics of fog. A lot of days with fog in awimet weather report
88.7  117.6 20-09-06 12:00    8  100     -2.8  8  2  99  0372
03 -- clouds developing 72 -- intermittent moderate snow
The camps and tracks look quite well developed.

133
Arctic sea ice / Re: MOSAiC news
« on: September 12, 2020, 09:31:43 PM »
I think we may be too harsh on mosaic. We have had loads of buoy data but it seems few are interested in it (or are willing to share their analysis). 1.4% of viewers can be bothered to look at recent ice temperature data to estimate thickness when it is practically spoon fed to them.
We need to up our own game and get some planks out of our eyes.

Im working on the stuff from last season but the data is pretty poor to be honest. There are 4 'active' thermistor buoys, but only T78 is providing reliable data at this point. The thickness for that one seems to be 90cm-1m.
Had a look at T81 and the data is challenging. The colder weather is helping at the surface but not really at the ice/ocean interface yet. Dropped to -1.69C on sep10.

134
Arctic sea ice / Re: MOSAiC news
« on: September 12, 2020, 04:13:16 PM »
I think we may be too harsh on mosaic. We have had loads of buoy data but it seems few are interested in it (or are willing to share their analysis). 1.4% of viewers can be bothered to look at recent ice temperature data to estimate thickness when it is practically spoon fed to them.
We need to up our own game and get some planks out of our eyes.

135
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 12, 2020, 03:22:11 PM »
mercator 0m salinity(SSS), jun1-sep11

136
Arctic sea ice / Re: The 2020 melting season
« on: September 12, 2020, 03:05:51 PM »
Probably not. We haven't had the teasing ups and downs yet.
mercator 0m temperature(SST) with amsr2-uhh sic overlay, jun1-sep11

137
Arctic sea ice / Re: MOSAiC news
« on: September 10, 2020, 10:43:50 PM »
It's probably going to take a while so moving delaunay development to the dev thread

thickness update. t81 may be showing some snow.

p234 drift speed

138
continuing from mosaic thread
squared up the grid and added some labels. Looking at adding some distances but tracking them is difficult as the delaunay lines move around. It is in the code somewhere though.

139
Arctic sea ice / Re: The 2020 melting season
« on: September 10, 2020, 05:09:49 PM »
I bet there is a nice rebound of 4+years  MYI this year <>
Ice age updated on the 7th of last month but nothing new yet. There was a reasonably clear view of, what must be some of, our soon to be 4+yr ice yesterday on noaa-20. https://go.nasa.gov/2DS1v1m

140
Arctic sea ice / Re: The 2020 melting season
« on: September 09, 2020, 11:57:55 PM »
amsr2-awi dev v1.03 latest
amsr2-uhh, sep8 for comparison.
awi dev possibly using later swaths.

141
Arctic sea ice / Re: The caa-greenland mega crack
« on: September 09, 2020, 11:11:23 PM »
The caa-greenland mega fracture https://go.nasa.gov/2FoXSQY

142
Arctic sea ice / Re: The 2020 melting season
« on: September 09, 2020, 10:52:09 PM »
Remember the JD storm in June UCMiami? That storm was weaker over then still a solid thick ice pack, and it did leave a mark. The difference was persistence of the wind, and it was a speculation of mine before this storm that the frozen melt ponds would leave the wind without much to grab onto. The ridges - that must have been still present in June - are all gone now. The ice must be dead flat right now right? And that is a lesson learned for me...
I think a mark has been left. Better unlearn that one. :)
https://go.nasa.gov/33gEmhs

More analysis here

143
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 09, 2020, 10:49:00 PM »
I think it's real. Noaa-20  https://go.nasa.gov/33gEmhs

144
Arctic sea ice / Re: MOSAiC news
« on: September 09, 2020, 09:37:02 PM »
First attempt at delaunay triangulation on the close Pbuoys. This only uses the hourly locations. lat/lon scale is in metres.
Lateral movement at this scale is too fast to view the small changes in position so one buoy's lat/lon (in metres) has been subtracted from all buoys. That buoy is at 0,0.

We should be able to tell when freeze sets in.
The 3d version might be interesting on this close set

Adding a fine grid adds another 5MB to the file size. Either there is quite a lot of movement within this 1.44km2 area or we are at the limits of gps tracking this far north. I forgot that the presentation is not square, will look into that (squashed it horizontally).
Data is from iabp The conversion from lat/lon to utm is from plot-svalbard, saved as csv. Delaunay is run in octave. data is attached below as text.

oops, now it's less than 500px (unsquashed)

145
Arctic sea ice / Re: MOSAiC news
« on: September 09, 2020, 03:14:35 PM »
drift update using T78.
Tbuoy temperature data. Not long to wait till core temp drops to allow us to get a clearer idea of where the ice/ocean interface is. updated below
P234 drift speed update

Thinking overnight about the Pbuoy deployment, we know that there were many more local buoys on the first floe. Perhaps they are sharing even more buoy data this time. I haven't had time to calculate any distances yet, but a close array of buoys might be useful for documenting reduction of motion during the early stages of the freeze cycle in relation to other measurements being taken.

Agreed, possibly a missed opportunity with the north greenland gap. Maybe they thought they had to get through it before it closed up.

146
Arctic sea ice / Re: MOSAiC news
« on: September 09, 2020, 12:11:50 AM »
What do you suppose the scientific objective is, releasing them so close together?
It's possible they are waiting for clear weather to distribute them but why not take some closer data while it's foggy etc.
If they don't redeploy it might be possible to create a more static presentation that shows very small lateral differences. Say, take the middle buoy and subtract its latlon from all the buoys. That would make it possible to maintain a very small focussed area at the loss of drift data. super zoomed delaunay.

Hopefully all genders feel equal on this thread.

147
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 08, 2020, 10:38:09 PM »
I think there's a good case for the low concentration area north of the Yermak plateau. North of Ellesmere Island looks like coastal upwelling which is the ultimate rough topography. North of Greenland? Surprising there is not more discussion. It's rough topography but with returning AW. Hardly any recent data. It's a shame that itp116 profiler failed before it passed right over that area. (failed at 88.3N on new years day). Mosaic was all further east.
So it's a reasonable connection but some may not be convinced  ;)

148
Arctic sea ice / Re: MOSAiC news
« on: September 08, 2020, 07:24:38 PM »
A squadron of new Pbuoys in tight formation
click for movement and lat/lon

added tbuoys

149
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 08, 2020, 05:45:43 PM »
Now, how long does it take for laptev water to reach the yermak plateau/north of Greenland?
my bolds
Quote
Cross-correlation analysis of time series of AW temperature measured at 250 m from 1997–2018 in Fram Strait, the entry point of AW into the Arctic, and from 2002–18 in the eastern EB (red time series in Fig. 5a) shows the strongest correlation, R = 0.67, for a lag of 682 days (Fram Strait series leads; Fig. 5b). The fit between the two time series is better over the last 7–8 years than it is over the earlier period. The ~2-yr lag suggests that warm pulses of AW that entered the Arctic Ocean through Fram Strait are traveling toward the eastern EB at a speed 2–2.5 times faster than that estimated for a warm AW pulse that entered the eastern EB in 2004 (Polyakov et al. 2005). This implies that the rate of advection has increased over time. However, noisy data due to gaps in the EB record preclude meaningful statistical analysis using just the early part of the time series. Assuming that the lagged correlation between the two time series will persist in the near future, the latest part of the Fram Strait series (not shown) implies that the AW temperature in the eastern EB reached its peak in late 2018 (these data are not yet available) and will slowly decrease over the next 1–2 years.

Does it take 2 years to get back to the north of Greenland?

Quote
Composite 2002–18 time series of (a) monthly mean potential water temperature θ and (c) daily depth of the lower halocline boundary Hbase defined by the 0°C isotherm at the M14 mooring location (for location, see Fig. 2). (b) Comparison of deseasonalized monthly mean time series of normalized θ anomalies from 250 m of the M14 mooring of the eastern EB (EEB) relative to F2–F3 moorings of Fram Strait lagged by 678 days (as obtained from correlation analysis); time series are normalized by their standard deviations.

150
Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: September 08, 2020, 04:10:49 PM »
Quote
How long does it takes to destroy the halocline over those areas and have a well-mixed ocean?
Quick answer. I don't know. I try to analyse what is happening now, presently attempting to link low concentration areas with possible turbulence.
whoi itp114 and other active itp's give us an idea of what is happening in the middle of the Beaufort today. Thermocline/halocline are still there. Temperature at 5m is ~-1C. Temperature at 50m looks to be on the high side but I haven't done a thorough yearly comparison. You could go back through the years and document the beaufort buoys. A few members would be very grateful and the data might give you a trend to work from.
Hopefully mosaic will deploy another itp near the pole to give us something to compare regarding atlantification.

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