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Messages - greatdying2

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1
Arctic sea ice / Re: Latest PIOMAS update (August mid monthly update)
« on: August 19, 2017, 02:29:24 AM »
Thanks Wipneus. A very useful update, as always.

It's worth keeping these in mind. I note that PIOMAS has not corrected the large anomaly near Svalbard -- will this now be perpetuated into the freezing season? I wonder if they are considering updating PIOMAS to assimilate CryoSat data...

2
Arctic sea ice / Re: Stupid Questions :o
« on: August 17, 2017, 09:45:33 AM »
Thanks Oren and Neven.

3
Arctic sea ice / Re: Stupid Questions :o
« on: August 17, 2017, 07:46:48 AM »
Already looked there. Can't find a thread with a posting this year that seems appropriate. And I don't like starting threads just to ask a question.

4
Arctic sea ice / Re: Stupid Questions :o
« on: August 17, 2017, 07:28:58 AM »
Question #1: Is there a way to block comments from specific users, and if so how?

Question #2: What thread do stupid questions like #1 belong in?

Thanks.

5
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 16, 2017, 06:45:04 PM »
It looks to me like the area fluctuations at least in the Laptev bite are due to cloud. The extent drops that Wipneus started to detect there, inside the ice perimeter, should continue and accelerate -- there's a large area of low concentration ice...

6
Arctic sea ice / Re: The 2017 melting season
« on: August 16, 2017, 07:10:52 AM »
Big drops in extent on the Pacific side again. Some also Atlantic and Russian sides, and a big area drop on the Russian side. The frequency and amplitude of area drop episodes on the Russian side are increasing and my guess is that it will start melting out within a week.

Attached Bremen 1 week 5-day 90 filter. See here for explanation and caveats:
http://forum.arctic-sea-ice.net/index.php/topic,2131.0.html .

7
Arctic sea ice / Re: The 2017 melting season
« on: August 14, 2017, 08:01:53 AM »
Pearscot, my take is that the ice is weak, but not so weak yet that breaking records doesn't depend on the weather. Also, the ice may not have been as thin as some models (esp. PIOMAS) predicted, due to the unprecedented weather last winter pushing the model in untested ways. Nevertheless, despite the slow start this season due to deep snow, and despite fairly nice ice-preserving weather, we may be heading for 2nd or even 1st (worst) place in different metrics.

Speaking of which, today's Bremen map (attached, last-under-90 filter) shows that: extent near the Beaufort has not stopped dropping, area in the central pack has recovered a bit after yesterdays big drop (probably noise in both directions), and the ice near Svalbard is starting to get into some serious trouble.

Edit: And the CAA is in trouble too.

8
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 14, 2017, 02:25:40 AM »
To quantify the amount of "artifacts" as you define them in the original image, you need to count the number of pixels your algorithm actually replaced. Those that were replaced by a lower value shall be known as "high concentration artifacts" while those that were bumped up shall be known as "low concentration artifacts".

That would certainly be easy and worthwhile to do. Not sure how it would help in choosing the "best" threshold, but it would be interesting to see the numbers. Note that the last-under-90 filter does not replace any low concentration pixels (but the quartile-based ones do).

9
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 14, 2017, 02:19:51 AM »
For a more realistic estimate, I wonder if it's possible to look at previous years and work out the probability that a pixel with 10%/20%/30%/40%/50%/(etc.) concentration will melt out by the time of the summer minimum, and then apply those probabilities to the current map.

Good idea. I have an idea along those lines too -- using classifiers (machine learning) to categorize pixels as melt / not based on the date, using previous years to train. Probably would use the original data instead of the concentration buckets used for the images. Would expect the classification to become more accurate as the melting season progressed. But no time now, so it's going to have to wait -- unless someone else wants to take a stab at it?

Also, A-team makes a very good point about the limitations of this approach on a pixel basis (as opposed to ice floes), and other problems. Not sure...

10
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 13, 2017, 09:11:53 PM »
Last bit of fun for now -- using the last-under-90 5-day filter, here is all the ice over 90 coloured white and under 90 coloured blue.

(NB: I don't think we will get anywhere close to this unless perhaps there is a late-season GAC, which looks unlikely based on current forecasts. But it's interesting to look at.)

11
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 13, 2017, 08:55:00 PM »
Hmm... it's a good idea to try to quantify that. So far it has just been from eyeballing it -- although backed up by the results, compare for example Q1 vs. Wipneus animation and Q3 vs. the same animation.

To quantify it, we would have to define mathematically what is meant by an artifact, which could be tricky. I suppose I could try to apply some kind of extreme value test... but that would assume that the artifacts only occur infrequently, which may not be true in this case.

Let me think about it and get back to you in a day or two. I don't have a lot of time today to play -- need to study for a job interview tomorrow  ;D .

If you (or anyone) have any suggestions about how to quantify it, I'm all ears.

12
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 13, 2017, 08:47:02 PM »
Looks like serious melting between Franz Josef and Svalbard.

Very much so. And it going to be hit by a storm over the next 2-3 days. I will be surprised if the whole Atlantic side isn't torn to pieces much like the Pacific side has been recently.

13
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 13, 2017, 08:34:34 PM »
Actually, I like Q1. It is basically a not-quite-minimum filter. Does a little smoothing, in regions of active melt is only 1 day "behind", filters out low concentration 1-day artifacts, and filters out high concentration artifacts even if they persist for 3 of 5 days.

Attached is Q1 for the last 2 weeks.

14
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 13, 2017, 08:22:36 PM »
For fun, here are the first (Q1) and third quartiles (Q3). Compare to the median above.

The period is 5 days, so Q1 is the second lowest value and Q3 the second highest. (Median is the third lowest / third highest.)

15
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 13, 2017, 07:12:38 PM »
Wipneus just posted a very useful animation of the basin ice:
http://forum.arctic-sea-ice.net/index.php/topic,382.msg125109.html#msg125109

For me, this re-confirms the usefulness of the last-under-90 filter. Take a good look at the details, all across the basin. The filtered image looks like reality.

The median filter does quite well too, but it is a bit blurry, a bit behind, and I think overestimates the concentrations a bit (because high concentration artifacts are far more frequent than low concentration ones -- I wonder if maybe a quartile filter might work... hmmm).

Attached are the latest full-sized last-under-90 and median filter images (5-day). (I'll leave it to you to guess which is which.)

16
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 13, 2017, 06:59:30 PM »
Arctic Basin animation.

Extremely interesting and useful animation -- thanks Wipneus.

17
Arctic sea ice / Re: What the Buoys are telling
« on: August 13, 2017, 11:06:16 AM »
Sure, of course it doesn't take a straight line. There are changes in wind direction, etc. But I thought you were talking about temperature and salinity trends that seem to be over at least the last 20 to 30 days? Maybe I misunderstood what trends you are talking about.

18
Arctic sea ice / Re: What the Buoys are telling
« on: August 13, 2017, 07:30:18 AM »
I was looking at ITP95.  It appears to me that the buoy is heading north from looking at the drift track. 

Isn't it drifting south (and into shallower waters)?

Latest location (triangle)

19
Arctic sea ice / Re: The 2017 melting season
« on: August 13, 2017, 06:24:19 AM »
Yes Sebastian, it's odd, isn't it? Also, a polynya appeared in the same location in 2012 and 2013. Must be a current.

Attached is the 1-day change (90% filter). Additional serious losses (perhaps area more than extent?) in and north of the Beaufort. Also looks like the Laptev bite may be preparing to recede.

20
Arctic sea ice / Re: The 2017 melting season
« on: August 13, 2017, 01:48:53 AM »
greatdying2: call me crazy, but is there a cloud artifact in your animation or is there actually a chunk of ice migrating in a couple days from the central siberian coast to the bering sea?

Yes, there is strong evidence of a new form of ice that has become airborne and sentient, and plans to recolonize the Earth. Just kidding  :o ;D yes it's a set of artifacts -- same on the original and the last-below-90 versions. One advantage of the median filter is that it eliminates artifacts such as these. (The minimum filter also would eliminate this artifact, but I no longer show it because I think the last-under-90 filter does a better job reflecting reality and is more responsive to day-to-day change.)

A-team -- The change is already impressive. The big question is, will it stop or will the next 2 weeks be as impressive... and nice find on that NOAA site!

21
Arctic sea ice / Re: The 2017 melting season
« on: August 12, 2017, 11:00:09 PM »
Bremen maps, 7 days ending Aug. 11. Original, median filter, last-below-90 filter. (Filters are based on 5 days ending on the labelled day. See previous posts for caveats.)

Pacific side continues to erode and looks like more area is thinning inside the new ice edge, preparing to do the same. But the Pacific side storms seem to be abating (for now), so maybe this thin ice can survive?

Atlantic side -- near-term forecasts suggest that maybe it is finally time for that side to get some bad weather. It will be interesting to see if the ice there is as weak as it has proven to be on the Pacific side.

22
Arctic sea ice / Re: The 2017 melting season
« on: August 10, 2017, 08:23:46 AM »
Bremen 1-week animations: unfiltered, last under 90, median (5 day filter).

23
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 09, 2017, 07:14:06 PM »
It is instructive to compare these different versions with this animation produced by Wipneus:

http://forum.arctic-sea-ice.net/index.php/topic,382.msg124478.html#msg124478

24
Arctic sea ice / Re: The 2017 melting season
« on: August 09, 2017, 07:37:00 AM »
Not to mention, it's getting pounded as we speak. This will be a telling week...

25
Arctic sea ice / Re: Solar wind storms effect on ICE?
« on: August 09, 2017, 07:30:37 AM »
Stupid question: If I post here, does it mean I'm stupid?  :o 8)

26
Arctic sea ice / Re: The 2017 melting season
« on: August 09, 2017, 07:17:30 AM »
1 day change in Bremen concentration. 3 versions attached: Original, last under 90 filter, median filter (5 day period). Choose your poison.

Pacific continues to erode and contract towards the CAA, with anti-clockwise motion in the direction of storm winds apparent throughout the Arctic, as anticipated by Sterks' post above. Such large scale coordinated motion cannot be good for the halocline.

27
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 09, 2017, 12:21:57 AM »
It's not cloud. The ridge can be seen in the ice on this Aug 4th image from WorldView. Could it be bands of thicker ice formed originally by ridging that are now moving? Similar patterns also appear in the areas that are melting out inside the ice perimeter.

28
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 09, 2017, 12:03:09 AM »
I forgot, I was going to post a version to show what happens if you select the most recent over 90% instead of under. Here it is (5 days).

Needless to say, this map is not very useful (except in helping to understand artifacts).

29
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 09:34:18 PM »
These occur after big storms, which are very real. Typically the ice concentration appears to drop sharply immediately after the storm, then rebound somewhat (and afterwards often continue to fall). I am not certain exactly what physical process is reflected in the rebound, but it is a pattern that can be predicted, not random noise.
Storms also have more atmospheric moisture - both as clouds and also just as more humid air.  So this pattern fits with a false low value (caused by cloud / atmospheric moisture) that then goes away as the clouds move, followed by continued decline - because it's melt season.  Personally I think this is the sort of process that ought to be filtered out if we are interested in real melting.

Yes and no. I think different filters are better for different different things. But you make a good argument, so how about this. In future I will post (at least) 3 versions: unmodified, most recent under 90, and median. Then people can look at their favourite, or even better,  compare them and draw their own conclusions.  :)

30
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 09:29:27 PM »
Edit:  "Most recent under 90" also clearly has a problem in areas where the true concentration is over 90, such as the area around 135W, 85-90N.  You can clearly see a spiral artifact appear over the course of 1-2 August as the core of the weather system passes overhead.  This then leaves a false "deposit" of low concentration pixels that lasts for several days - because the real concentration is over 95% and thus cannot overwrite the false low values.  The artifact is even larger (and just as false) in the "Most recent under 95" animation.  If you look at the Earthdata images in the right wavelengths, you can clearly see that the ice sheet in this region is unbroken and snow covered, at ~100% concentration.
https://go.nasa.gov/2vM23QD

Yes, I agree that this is an artifact. Furthermore, basically all of the "yellow streaks" in the "large purple area" are artifacts (as I suggested above).

Luckily, these are easy to see and to ignore. And besides, they are not in an area of much interest -- unless someone thinks a polynya might be forming here. The main purpose of these filters is to better watch the evolution of marginal ice zones during the melt season without being distracted by frequent cloud artifacts.

31
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 09:21:06 PM »
Most recent under 90% (5 days).

Compared to the median version above, this version does a better job at showing daily changes, for example the alternating loss and recovery cycle ("breathing") on the Pacific side

What is your basis for believing this apparent cycle (i.e. where an unusually high/low value goes away the next day) is real, and therefore this filter is better?  There seems to be no plausible physical mechanism that would cause it. On the contrary, this is exactly what you expect from random noise. Large excursions away from the true value will typically revert towards the mean the following day.

These occur after big storms, which are very real. Typically the ice concentration appears to drop sharply immediately after the storm, then rebound somewhat (and afterwards often continue to fall). I am not certain exactly what physical process is reflected in the rebound, but it is a pattern that can be predicted, not random noise. As I said in an earlier post, it's clearly not "real" in the sense that new ice is not forming, but as a guess it may result from ice that has been drenched in waves drying out and thus is useful to detect. If it was just random noise, the timing wouldn't coincide with storms.

32
Arctic sea ice / Re: PIOMAS vs CryoSat
« on: August 08, 2017, 08:54:46 PM »
There are two sources for CryoSat-2 derived Sea Ice Thickness. The Alfred Wegener Institute (AWI), and the Centre for Polar Observation and Modelling (CPOM). I have not seen any comparison between these two products, so here is a comparison of the AWI final product and the CPOM 2 day, 1km NRT product for January to April 2017. There is no great difference between the NRT and final AWI products, so this seems a reasonable comparison.

Thank you again Michael. These are a great help.

So there do seem to be some systematic differences between AWI and CPOM; however, they are relatively low in magnitude, less than half a metre one way or the other except in certain small regions (immediately adjacent to Greenland and the CAA).

Nevertheless, if I am reading these correctly, CPOM agrees with PIOMAS (a bit) more closely than AWI does?

33
Arctic sea ice / Re: PIOMAS vs CryoSat
« on: August 08, 2017, 08:52:10 PM »
Is it fair to say that from this animation of PIOMAS-AWI :

that at least w.r.t. Cryosat2 that PIOMAS overestimates thickness of the thinner ice on the boundaries of the Arctic basin, and possibly underestimates ice in the CAB ?

If so, it would explain some of the features in Wipneus' PIOMAS volume anomaly graph :
https://sites.google.com/site/arctischepinguin/home/piomas
and specifically the fast drop in June and the re-bound in July of the years that go low...

Yes, I completely agree.

34
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 08:48:26 PM »
facts remain exacxtly that and these images show the short/mid term development in a most comprehensive way

Thanks magnamentis, I'm glad that I'm not the only one who finds them useful!  ;D

35
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 08:36:11 PM »
This is great
There is, however, an issue which is how filter affects motion (translation or massive drift as Tor Benjar points out it happened today).
See, when a package translates and one uses a filter that does not take into account advective phenomena such as flows, drifts, or waves, funny things may result. The median filter just blurs the package in the direction of the movement. But a selective filter would tend to maintain a "wake" behind the translating package if it is low concentration (just like the ping pong character moving in the old phosphorescent monitors), and tend to make disappear a high concentration package.
All this would be difficult to evaluate in this animations, admittingly, but this is no artifice to be eliminated: drift exists and is very real, the same for high concentration or low concentration ice.
Excuse the long explanation

Good point. For drifting low concentration ice, the "most recent" filters can capture it -- provided it has not been obscured by a cloud artifact -- because they just use the most recent value as long as it's below (e.g. 90%). These filters would however fail for high concentration ice drifting quickly through low concentration areas. The high concentration ice would basically get erased by the filter if it was moving quickly enough.

Edit: Oh I see now what you mean by a wake. Yes, low concentration ice drifting through a high concentration area would indeed leave a low concentration wake when using these filters.

Edit2: I think I should compile a list of caveats to post along with these filtered images, which should include at least: 1.) Low concentration cloud artifacts are exaggerated; 2.) High concentration ice that is moving quickly through low concentration ice can be erased by the filter; and 3.) Low concentration ice that is moving quickly through high concentration ice can leave a wake.

Any additional caveats?

36
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 08:30:45 PM »
I also tried most recent under 95%. The results are passable but not as useful I think as the 90% threshold.

37
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 08:18:03 PM »
Most recent under 90% (5 days).

Compared to the median version above, this version does a better job at showing daily changes, for example the alternating loss and recovery cycle ("breathing") on the Pacific side, and the big extent gaps forming on the last frame (Aug 7). That's why I prefer this filter for daily use. Median is better suited for long-term trends.

By the way, I found a bug in a boundary condition which resulted in red (85%) being filtered out in previous versions. Fixed here. Also, in previous versions I had been replacing dark purple with lighter purple in some cases, which I am no longer doing.

38
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 08:10:01 PM »
Median (5 days):

39
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 07:56:23 PM »
You're welcome Peter. It's a fun project and the products are useful at least to me in figuring out what's going on with the ice.

I agree that the median filter is the most mathematically elegant and gives the smoothest result. Also, unlike the other filters, it would work equally well during refreeze (although ice concentration probably isn't very useful during refreeze, since I guess it will quickly become 100% in most areas). However, it suffers from the disadvantage that it is slow to respond to daily changes.

As to justification, seaice.de offered a technical justification here:
http://forum.arctic-sea-ice.net/index.php/topic,1834.msg123495.html#msg123495

Personally, I think the results are justification enough -- at least for use as an amateur tool. Compare the filtered images to the originals and to other evidence of the ice concentration such as satellite images. I find that the filters succeed in removing the obvious, fast-moving noise (apparently caused by cloud) and allow me to better see where the ice is thickening, thinning, or approaching the 15% threshold.

To demonstrate this again, attached is a gif of recent days, unfiltered. Look for example at the ice near the Chukchi/ESS around July 28 and again around Aug 4. Large areas become purple for a day or so and then revert back to lower concentrations. If you check WorldView, you will see that these 'purple flashes' correspond to areas and dates of thick cloud cover.

Then look at the filtered versions -- attached to following posts. They eliminate most of the purple flashes, and instead show a record of an earlier value (exactly what value they show depends on the algorithm).

This approach obviously would do a bad job at reflecting reality if low concentration anomalies were anywhere near as pervasive as high concentration anomalies. But they don't seem to be. I have been searching for them and although I do find one occasionally (see previous posts), they are rare. Indeed, this can be easily verified by looking at the high concentration area near the CAA. If low concentration artifacts were common, the filtered images would not succeed in retaining this large purple area. But, apart from a few small blemishes, they do succeed.

For additional justification about the "direction of the noise", I tried applying some inverse filters. That is, instead of for example filtering out concentrations above 90%, I filtered below 90%. The results of this exercise do not come anywhere near to reality and show just how common high concentration artifacts really are. (See following posts.)

Here is the unfiltered version:

40
Arctic sea ice / Re: The 2017 melting season
« on: August 08, 2017, 07:56:58 AM »
Bremen NIC, 7 days ending August 7th, filtered.

More extent loss today on Pacific and a little in the Laptev bite.

(NB: The attached Bremen map has been filtered by using for each pixel the latest concentration under 90% (not purple) over 5 days ending on the date labelled. See: http://forum.arctic-sea-ice.net/index.php/topic,2131.0.html)

41
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 06:10:43 AM »
Found a good example of a current low concentration anomaly, a yellow streak in a 90+% concentration area of the Beaufort that appears to be caused by an odd-looking cloud that barely moves over a period of 2 days.

42
Arctic sea ice / Re: The 2017 melting season
« on: August 08, 2017, 05:07:25 AM »
A-team, those are terrific visualizations. On the first one, is there supposed to be a difference between the top and bottom panels? The second one, showing daily deltas, really does a good job illustrating the amount of ice being melted on the Atlantic side even as more keeps getting exported.

43
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 08, 2017, 01:21:37 AM »
Here is an overlay of the latest (Aug 6th) v1.2 Bremen filter with a Wipneus PIOMAS thickness map and a Cryosat map that Michael just posted showing the difference between PIOMAS thickness and what Cryosat detected, both from April. (I haven't been able to find a map directly showing the Cryosat measured thickness.)

Visually, it looks to me like the Cryosat April thickness does a very good job at predicting the melt at this point as well as other features of the Bremen map, including the high concentration arm extending towards the ESS.

http://forum.arctic-sea-ice.net/index.php/topic,119.msg112164.html#msg112164
http://forum.arctic-sea-ice.net/index.php/topic,8.msg124238.html#msg124238

44
Arctic sea ice / Re: PIOMAS vs CryoSat
« on: August 08, 2017, 12:46:58 AM »
Here is an overlay of Michael's difference map with Wipneus' map of PIOMAS thickness, both from April.

45
Arctic sea ice / Re: The 2017 melting season
« on: August 08, 2017, 12:16:20 AM »
Speaking of thickness, here is the PIOMAS modelled thickness from April, and how much it is off by based on Cyrosat measurements.

Together, this does seem to support an arm of thicker ice in the CAB next to the ESS.

http://forum.arctic-sea-ice.net/index.php/topic,119.msg112164.html#msg112164
http://forum.arctic-sea-ice.net/index.php/topic,8.msg124238.html#msg124238

46
Arctic sea ice / Re: Latest PIOMAS update (August)
« on: August 08, 2017, 12:06:30 AM »
Personally I am highly sceptical about any model. Useful? Definitely. Truth? Definitely not. The real question is, in what ways is it useful and in what ways is it not.

Hopefully everyone has already seen this: http://forum.arctic-sea-ice.net/index.php/topic,8.msg124238.html#msg124238

47
Arctic sea ice / Re: PIOMAS vs CryoSat
« on: August 07, 2017, 11:44:49 PM »
Terrific! Thank you Michael.

Did AWI (or anyone else) make maps yet of the original (as opposed to the difference with PIOMAS) thickness detected by Icesat?

48
Arctic sea ice / Re: The 2017 melting season
« on: August 07, 2017, 09:55:11 PM »
Then for the following 2 days, the storm moves on to the Chukchi and Beaufort, where it almost certainly will do easily measurable damage, and a lot of it.

What will the storm do after 3 days...?

49
Arctic sea ice / Re: The 2017 melting season
« on: August 07, 2017, 09:41:07 PM »
Tomorrow, the latest storm will pass over the arm of higher concentration and probably thicker ice near the ESS. It will be interesting to see in the following days whether it will do much measurable damage.

(NB: The attached Bremen map has been filtered by using for each pixel the latest concentration under 90% (not purple) over 5 days ending on the date labelled. See: http://forum.arctic-sea-ice.net/index.php/topic,2131.0.html)

50
Arctic sea ice / Re: Ice Concentration Images and Animations
« on: August 07, 2017, 09:16:10 PM »
Thanks sedziobs and magnamentis for your suggestions.

Regarding the median filter, while I agree that it tends to look somewhat like older pictures, what it actually shows is the middle value of the last N days (half way between max and min), not the value of the middle day. In regions where there is an ongoing melt, this would indeed make the image look similar to a smoothed version of the middle day. So I see what you're saying, but I'm not sure relabelling would make sense (to me).

Pausing is definitely a good idea. I have actually been adding a brief pause (first and last frame are doubled), clearly it needs to be longer. :)

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