This is Neven's Typepad Profile.
Join Typepad and start following Neven's activity
Join Now!
Already a member? Sign In
Neven
Recent Activity
I used those MODIS composite images back in 2012, by the way (see here), and vaguely remember that there was some sort of archive where you could look at MODIS composite images from previous years. I can't seem to find it now, though. It'd be interesting to compare the current ones to those of 2012.
The 'Arctic' MODIS Composites images (False-Colour and True-Colour) from the Canadian Ice Service has not been updated for over two weeks now, when they are normally updated every week. Could you please look into this? I'm sorry, Zorro Spacemail, but I'm too busy. Maybe you could shoot off a mail to Environment Canada?
and now Top 3 is no longer ruled out. You're going to have to quote me on that, as I can't remember having said that. I have said many times now that the top 3 isn't a certainty, and going as low or lower than 2011/2015 (NSIDC September minimum) will not be easy if the weather stays as it has been for the past 6-7 weeks. On the July poll I have voted for 'between 4.5 and 4.75 million km2' (2011 and 2015 each had 4.63 million km2). I apologize for relying on what I have learned during the past 7 melting seasons, and for refraining from announcing The Day After Tomorrow every single melting season. I think the (long-term) situation is alarming enough without having to resort to short-term alarmism.
How's that for suspense, eh? ;-) Sometimes while I'm writing, I think of something else I want to write, do that first and forget to finish the other thing. Thanks for checking.
Also be sure to read the latest analysis on the NSIDC website.
Image
During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Because of issues with data based on the SSMIS sensor aboard DMSP satellites, I mainly focus on higher-resolution AMSR2 data from the Japan Aerospace Exploration Agency (JAXA), as reported on the... Continue reading
Posted 5 days ago at Arctic Sea Ice
61
Tamino has a blog post on Arctic Heat.
Toggle Commented Jul 17, 2016 on Iced lightning at Arctic Sea Ice
Image
From a children's book: "In The Legend of Lightning and Thunder, a traditional legend that has been told in the Kivalliq region of Nunavut for centuries, two siblings resort to stealing from their fellow villagers, and inadvertently introduce lightning and thunder into the world. This beautifully illustrated traditional legend weaves... Continue reading
Posted Jul 16, 2016 at Arctic Sea Ice
22
Clearly there is a problem with the model when it shows no melt ponds when anyone on the internet using NASA's web sites can see melt ponds where the model says there are none. Fish, I stated why I find the model results interesting (as a comparison to previous years), but that doesn't mean I'm going to defend the model as being the best thing since sliced bread. No one is saying this, least of all the people from CPOM. However, I'm going to have to repeat the caveat that "the distribution of melt ponds doesn't necessarily reflect reality." And also that the maps you're seeing show anomaly from the 10-year average, not the existence/absence of melt ponds per se. If it's blue it means there's less melt ponds than on average (white is the same, red is more melt ponds). This doesn't mean there aren't any melt ponds there.
Toggle Commented Jul 14, 2016 on 2016 melting momentum, part 3 at Arctic Sea Ice
Thanks, Wayne. I'm not ruling out anything you're saying, but this blog post simply reflects how I'm seeing things as of now. I will keep watching, of course, and adjust my views when needed (do that every day anyway ;-) ). I'm doing a new ASI update this weekend. We the Borg, are always gunning for perfection. 100% accuracy is what we live for, those who don't adhere will be assimilated.... But resistance is welcomed, as long as it is polite like most Canadians. PIOMAS lacks in situ verification, its always good to be skeptical about it. Actually, speaking of assimilation, that's the A in PIOMAS (Pan-Arctic Ice-Ocean Modeling and Assimilation System). As it says on the UW Polar Science Centre website: Purpose Sea ice volume is an important climate indicator. It depends on both ice thickness and extent and therefore more directly tied to climate forcing than extent alone. However, Arctic sea ice volume cannot currently be observed continuously. Observations from satellites, Navy submarines, moorings, and field measurements are all limited in space and time. The assimilation of observations into numerical models currently provides one way of estimating sea ice volume changes on a continuous basis. Volume estimates using age of sea ice as a proxy for ice thickness are another useful method (see here and here). Comparisons of the model estimates of the ice thickness with observations help test our understanding of the processes represented in the model that are important for sea ice formation and melt. Things like IceBridge and CryoSat-2 data are incorporated as much as possible. No model is perfect, but PIOMAS really is kick-ass and an invaluable tool.
Toggle Commented Jul 13, 2016 on 2016 melting momentum, part 3 at Arctic Sea Ice
The Uni Bremen SIC map is observational data (passive microwave), the Navy product is model-based and has a history of errors, glitches and artifacts. Coincidentally, there's a topic on the ASIF about this very subject.
Toggle Commented Jul 13, 2016 on 2016 melting momentum, part 3 at Arctic Sea Ice
I'm not interested in 100% accuracy, I'm interested in comparisons between years. If melt pond fraction is simulated in the same way every year, I can use this information to get an idea of the range of possibilities, which makes it easier to write. And as far as models go, I think PIOMAS is quite kick-ass. There is always room for improvement, but as things stand, we have a pretty amazing set of tools at our amateur disposal.
Toggle Commented Jul 13, 2016 on 2016 melting momentum, part 3 at Arctic Sea Ice
Baffin Bay sea ice is going away real fast now. Yet the anomaly model suggests it was cold there. It doesn't suggest that. The blue means there were less melt ponds there, compared to the average for the last 10 years. That doesn't mean the model is predicting that Baffin Bay won't melt out. And in fact, just like last year, Baffin Bay is melting slower than many a year, because it was relatively cloudy in the past few weeks. But anyway, I'll repeat, from the blog post: Caveat: This is a model result, and so the distribution of melt ponds doesn't necessarily reflect reality. And from the 2014 Schröder et al Nature paper: The CICE simulation in this study uses NCEP_Reanalysis-2 data13 for the atmospheric forcing which are available with a delay of less than one day. Don't bash the model if you don't even know exactly what it is doing. And if you can, point me to a better model or observational method that tells me something about melt pond fraction/distribution.
Toggle Commented Jul 13, 2016 on 2016 melting momentum, part 3 at Arctic Sea Ice
I just think that there are other perspectives out there (like Dr. Slater's model) that deserve attention. You're right. I will try to mention it in upcoming posts, as the model is getting more interesting/accurate as the melting season progresses. I just have to make some effort to try to understand how the model works and what anomaly persistence is. ;-) That heat went somewhere, and despite the lows in June, statistical averaging suggest that that heat WILL come and bite us at some point. Oh, it will bite us at some point, I'm just not sure if that bite will be (clearly) reflected in September extent numbers. Maybe in the end, this melting season is a test of the influence of "albedo" feedback in general against the effect of "melting ponds". Definitely. That's why I ended this blog post with: "I have a feeling this melting season will teach us some more valuable lessons." The thing with melt ponds is that they're situated right there in parts of the ice pack that are tough to melt out in the final phase of the melting season, as they are so far North, often thicker multi-year ice. Melt ponds are a direct conduit for solar radiation into the ice pack, unlike open water in the periphery, or land masses even further away. Things have simply been too cloudy over too much of the Arctic for too long (even as we speak, and forecasts aren't showing any big changes), although I will admit that this has been a crazy melting season for the greatest part of the year, and I'm not at all sure that even a non-top 5 ranking will mean the ice has been let off the hook. There are things going on that aren't boding well at all in the long term, like the massively dispersed ice front on the Pacific side of the Arctic (especially Beaufort) and the massive heat and open skies over the CAA and oldest ice region just above it. And all the heat - SSTs are really high all over the place - that doesn't go into ice melting, will be released into the atmosphere come September and October, messing up weather patterns further. There's September extent, and then there's long-term changes.
Toggle Commented Jul 13, 2016 on 2016 melting momentum, part 3 at Arctic Sea Ice
I understand that you have some preference to highlight Dr. Schröder's model prediction (of 5.2 M km^2 in September). But considering that his SIPN July projection last year was about 700 k km^2 too high, and considering that according to Wipneus' AMSR2 extent ratings, 2015 is still running some 600 k km^2 below 2015, what makes you think this year his projection will be any better ? Rob, I see it as a very useful piece of information on melting momentum. As you know, I think this phenomenon has a big influence on the final outcome of the melting season, extent-wise. I don't think it's all-important, however. There are many other factors, like sea ice volume and ocean heat flux, for instance. But I do think, that at current volume levels, a lack of melting momentum can thwart record attempts. And in the case of this year, a top 3 ranking. As you can read in this blog post, I personally believe the September average will end up somewhere in the lower range of Schröder's prediction. I think 5.2 million is too high as well, but that's what his simulation produces. The main reason I highlight it, is because I think it's important research (and public attention may help securing grants for further research) and I'm grateful to Dr Schröder for sharing data in the shape of melt pond fraction maps, as he's probably quite busy. But again, I think melting momentum is important, and this information is a very useful piece of the puzzle. I hope that in the near future we can add observational data as well (like the stuff Anja Rösel was working on a few years ago).
Toggle Commented Jul 13, 2016 on 2016 melting momentum, part 3 at Arctic Sea Ice
Image
Melting momentum, it's what I call the absorption of heat and solar radiation during May and June that does not directly lead to melt and a reduction in ice cover, but rather comes into play during July and August (I had a more wordy explanation last year). This is part... Continue reading
Posted Jul 12, 2016 at Arctic Sea Ice
66
Indeed, crandles, it's just barely open on the Uni Bremen SIC map. It's amazing, as I thought I was being conservative back when this blog post was written. Just a few more days of wind blowing away from the coast, or after that just some heat to melt it in place. But none of that happened, winds started blowing the other way, and here we are, six weeks later. What can I say? It's the Arctic. :-)
Toggle Commented Jul 11, 2016 on Beaufort final update at Arctic Sea Ice
There's a good article on PIOMAS over on the UW Today Blog (University of Washington).
Toggle Commented Jul 8, 2016 on PIOMAS July 2016 at Arctic Sea Ice
Yes, new records really seem to be out of reach now, but I still feel that a top 3 position could be obtained relatively easily. There's something about this melting season that I can't quite put my finger on. Maybe it's the high SSTs, and the realization that it may take compaction to break records, but it will take dispersal to go ice-free (as soon as volume is low enough, that is). Either way, what we'd like to see, is a return to pre-2005 levels, but things just keep looking ugly.
Toggle Commented Jul 8, 2016 on PIOMAS July 2016 at Arctic Sea Ice
Rob, that would make it easier to find if ever needed. :-)
Toggle Commented Jul 7, 2016 on ASI 2016 update 3: crunch time at Arctic Sea Ice
The ECMWF shows a stunning heat wave developing on the Atlantic side of the Arctic according to the 850mb temps. Those temps under high pressure over an area where the sea ice has retreated the most will warm the open waters to possibly unprecedented temperatures over the next 10 days if the forecast verifies. The DMI SST map as well as NOAA's and the reanalyzer show temperatures in the Barents and Kara seas are already way above normal. The build up of heat on the Atlantic side will affect this year and also 2017 because the heat pulse around Svalbard runs deep. What a coincidence, Fish. I just wrote about that this evening for the latest PIOMAS update: "Although clockwise drift speed has been higher in the Central Arctic during the first half of this year, it doesn't seem to have resulted in as much export through Fram Strait as during the 2006-2016 period. I'm not sure how important this is, as this year the heat has decided to come to the ice, instead of the other way around."
Image
Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center: As expected after a month of stalling sea ice extent and weather that generally isn't conducive to sea... Continue reading
Posted Jul 6, 2016 at Arctic Sea Ice
20
Image
The first Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2015 Arctic sea ice extent, based... Continue reading
Posted Jul 5, 2016 at Arctic Sea Ice
29
JAXA finally reports a century break (just the fourth this melting season so far), and 2016 is now lowest on record again.
Toggle Commented Jul 5, 2016 on ASI 2016 update 3: crunch time at Arctic Sea Ice
Some ice bloggers say 2016 won't even make it into the Top 3 lowest years for autumn minimum. Show us where they say that. Give us the quotes. And in contrast, explain to me how this year is 100% sure to make the top 3 (NSIDC SII September extent), no matter what the weather does. I fear this may be just another round of wishful thinking. You mean like the annual announcement that the Arctic is going to go ice-free this year? --- I'll repeat: This year has many things going for it, but June usually needs to be sunny and warm for extent to go really low in September. This wasn't the case, so now in July and August something extra needs to happen, like a persistent sunny period, extreme SAT and SST anomalies, or maybe some crazy cyclone, for this year to go as low as 2007, 2011 and 2012. If nothing extra comes and the weather of the past few weeks is prolonged, this year will not make the top 3. I don't see how anyone could disagree with that, unless he believes in undersea volcanoes or some other invisible forcing that must be really, really bad because we can't see it. But of course, as said, the weather forecast is hinting at something that could be considered extra. It's not going to be dull. Unlike others I'm open to multiple possibilities. :-)
Toggle Commented Jul 4, 2016 on ASI 2016 update 3: crunch time at Arctic Sea Ice