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Ouch ... the new Navy Hycom algorithm is way off-base. Operationally, a couple of stops past hazardous -- far better off with direct imagery. The old algorithm is being irrevocably decommissioned on 31 Aug 13 -- too bad, it had some good weeks. The fade-out animation has 5% transparency increments. It is slightly posterized because of the gif restriction to 256 colors despite Floyd-Steinberg dithering. Hycom has 29.4% the resolution of 89 Ghz Jaxa and so had to be upsampled for the overlay.
Toggle Commented Aug 23, 2013 on Hole at Arctic Sea Ice
I'm starting to appreciate the full gamut of microwave frequencies -- a learning curve with it but eventually it starts to make some sense. The one below might have some predictive value for the week ahead.
Toggle Commented Aug 22, 2013 on Hole at Arctic Sea Ice
Hycom ice color has always been jpg'ed and never corresponded to the colors in the key (which was added back to the image afterwards). The third mistake was not doing the key initially as overtint of a uniform grayscale. Thus it is all but impossible to fix the palette without drilling down into their file system to find the raw numeric array, assuming they archived that. Grayscale is the universal scientific standard for numeric manipulation of images displaying 1D data (concentration, thickness etc are maps: I^2 -> +R^1). As things stand, we have no real mechanism for quantitative comparison of new and old. For what it was worth, I subtracted the two 01 Aug 13 images Blaine supplied, adding neutral gray 128 to keep everything within bounds [0 255] while sticking to native resolution (1/12º ~ 10km/pixel). (Their documentation speaks of 3.5 km resolution at the pole, applicable perhaps to the one map inexplicably offered in Mollweide; the rest are stereographic. There, simply count pixels from pole to the Siberian shore grazed by 70ºN to determine resolution.) I've always wondered where the heck they get their underlying imagery and why they don't check in occasionally with something better to ground the product model in observation. Ice thickness seems to be calibrated off a sparse radar altimeter: "NCODA assimilates available satellite altimeter observations (along track obtained via the NAVOCEANO Altimeter Data Fusion Center), satellite ice concentration..." The satellite instrument and concentration algorithm are not specified but I suspect none of the ones we use. This is a highly sophisticated model outputting a product that never stood up to the slightest scrutiny -- seemingly the paradigm for climate science modelling (no result, publish anyway): "Hydrostatic approximation, hybrid pressure coordinate, fourth-order LaPlacian for vorticity, divergence, virtual potential temperature, specific humidity, surface pressure, ground temperature, ground wetness, cloud fraction, horizontal spectral differencing, second-order finite difference in the vertical, central time differencing with Robert semi- implicit corrections,42 sigma levels with 6 sigma below 850 mb,00Z, 06Z, 12Z and 18Z ops run, Machenhauer initialization, NOGAPS 6-h or 12-h forecast, spectrally truncated and Lanczos filtered heights, convective precipitation (Emanuel), shallow cumulus mixing (Tiedtke) and large-scale convection, long-wave and short-wave radiation (Harshvardhan) computed every 2 hour, gravity wave drag, planetary boundary layer, sea surface temperature and ice coverage percentage from OCEAN MVOI."
Toggle Commented Aug 22, 2013 on ASI 2013 update 7: cold and cloudy at Arctic Sea Ice
Abrupt disconnect over at Navy Hycom, as first noticed over on the forum. They've radically increased the thickness and altered distribution of first year ice. Some models need to 'tie in' periodically to observational data to reset themselves to reality. Fine. But where would that come from with ice thickness in mid-August? Apart from correct peripheral ice boundary, they're still wildly inconsistent with high resolution satellite display of unambiguous open water [Modis and 89Ghz], 2 m being worse than before. If this is an revised algorithm, how was it judged ready for release? I could find no explanation offered -- surely they have an unpaid intern not too busy to write up a few lines. I'm not sure how far back they are recomputing but 01 Aug 13 at least. Also it appears they have overwritten previous 30 day runs. What then becomes of year to year comparison?
Toggle Commented Aug 21, 2013 on ASI 2013 update 7: cold and cloudy at Arctic Sea Ice
Yes, indeed DanP. Also contact earthdata.nasa since you have improved on their offering in a way that will interest many end users. For the hdf and netCDF files, I'll remind people of free desktop software Panoply. However 18 GB of daily download is not going to prove feasible for most people. And when downloaded, you cannot afford to experiment on very large files so get your pipeline down on smaller test files. Even the last few weeks, which have seen very little coherent ice motion, still introduce too much jitter into an eight day product relative to 0.5 km pixel resolution, so three cheers for 2.5 days. While floe motion vectors are supposedly provided daily and Gimp etc offer very nuanced motion blur correction, I'm sceptical that these could really improve time-composited ice imagery, though 2.5 days is a lot more favorable for that. I looked at band 31 (11 micron infrared, 1 km resolution) on earthdata.nasa to see if it offered anything to complement the shorter wavelengths you have been using but it has mostly to do with cloud temperature. Oblique cloud shadows on ice are removable -- unlike thick clouds directly over ice. Cloud height could also be obtained from the sun angle at swath time. In fact, an overall daily cloud/fog/vapor product from all the wavelengths out there would be very useful for interpreting conditions affecting the ice.
Toggle Commented Aug 21, 2013 on ASI 2013 update 7: cold and cloudy at Arctic Sea Ice
Summer brings clouds whose water vapor interferes with analysis, then and now, so take-home lessons of cyclones for the ice are not fully realized. Despite incredible efforts of Danp on best-swaths and pixel by pixel cloud mask, which have gone retrospective over on the forum. For sure, the pipeline products we use have not found a solution to impenetrable clouds. For example, what is going on here -- your choice of melt / divergence in an unexpected place vs cloud artefact implausibly affecting very different wavelengths:
It may be difficult with shelf methane to improve on satellites + more frequent field campaigns. It is far easier to measure methane in the air column than local methane supersaturation in water. I was going to suggest building additional icebreakers to augment interpretation of satellites -- notably our best instrument AMSR2 -- beyond what more buoys could do until I came across the USCGC Healy web site and found it takes a whole lot of resources to get very little done. The Healy has not ventured out into the ice in 2013 and have no plans to do so. First, BOEM engaged them to carry out fatuous oil spill containment exercises -- Commercial-Off-The-Shelf (COTS) and Government-Off-The-Shelf (GOTS) technologies -- apparently to prop up justification of the oil drillng program. The logistics of containment based out of the nearest Coast Guard station (Kodiak, a thousand miles away) is completely unworkable ten months of the year. Next, acoustic releases to service 5 moored buoys and installed 9 new ones, making some near-shore current and salinity measurements in the vicinity of Barrow Canyon, Admundsen Gulf and Hanna Shoal. Ok. The final cruise towed CHIRP sonar and made shallow cores with occasional CTD stations and thermister drops, with the major cruise objective finding "geological evidence of a massive flood that came north to the Arctic via the Mackenzie River about 13,000 years ago." Fine. We're not learning anything about the new ice situation though. Here they are -- circling over a lease within rowboat distance of Barrow, being serviced at Vigor Marine in Seattle:
Like doom, I was underwhelmed by the piece. Cyclone commentary seems to bring out a lot of she said, he said divorced from statistically rigorous analysis, personal reminiscences about events no one experienced that occurred in a vast under-instrumented area. That October 2012 article on the Great Cyclone that everyone disses is actually built off an exhaustive Arctic cyclone catalogue. I don't recall them actually providing a link to the database but it cannot be withheld from a request under the journal matériel clause. It is reanalysis-based but the lag time is short enough that this summer's events would be included. The database contains a half-dozen fields characterizing the cyclone, such as maximal low, pressure gradient, wind speed, duration, and so forth. These have a lot of redundancy but upon principal component analysis, I wouldn't be surprised if the first component alone captured 80% of the covariance and could be used as a single number to quantitate and plot cyclone intensity over the years.
If this thread develops, perhaps one person could take it upon themselves to fill out the form with our better ideas on the 23rd August deadline. Open journal access is a real imperative -- retention of copyright and free online provision required by funder (as is required in so many scientific fields). Climate change especially needs expedited distribution of information. That geothermal heat flux article was submitted on 20 Dec 2012 and is just appearing now. Behind a $32 paywall. Too bad, it is quite an interesting article. Open review at Cryosphere Today is a far better paradigm. Peer review has deteriorated over the years -- scientists are expected to publish a kazillion articles per year, so it's not in your self-interest to volunteer for thankless energy-sapping tasks. Reviewers on my last three papers were clueless ... people not qualified to edit wikipedia articles. Talking about top-ten impact journals here, backwater would be worse. The Fram has been a mix lately of nothing being exported or stuff melting before it gets anywhere. Here is higher resolution view of that odd melt development (shown above by the purple arrow for the 6V microwave) and some other peculiar nearby features (that require 2-3 days of consecutive appearance to validate).
I'm heading up to Alaska next week for a look-see and thus offline ... with a month to go in melt season. Jai, great idea to monitor the bubbles better; we need to double down on methane across the board, get ahead of the curve for once. Opening of s nw passage can be seen on 6 Ghz too -- but look at the odd spot that's been opening up between the Pole and Nord. The melt pattern has been quite odd this year for sure.
First thing they need to do is define what they mean -- and don't mean -- by Arctic. For the Arctic Ocean proper, I would say it is grossly under-instrumented right now, especially relative to its role as first domino to fall in climate change. So we see statements like this (from EUMETSAT OSI SAF): "Due to high atmospheric Liquid Water Content and to ice surface melting, it is not possible to track ice motion during Arctic summer, from the channels we are processing. Accordingly, the NH product files distributed between May, 1st and September 30th do not contain any valid [motion] vector." IceBridge provides a few 1D tracks whereas IceSatII will be coming too late if at all. Meanwhile the current satellite sensors cannot see down to the ice during melt season and when they do, the resolution is too low and usually have nothing by way of contemporaneous ground truthing. There's no easy answer here. The buoy program is a joke -- 3 orders of magnitude too few, can't be sure of them to reporting reliably, no within-buoy instrumental redundancy, they aren't getting all the properties of ice we need, coupled with poor documentation of online raw data that shuts out the broader community. We haven't done anything serious on this site with changing upwelling and downwelling radiative energy fluxes (Calypso radiometer) or Arctic cloud data -- yet those and currents are the main drivers downstream. While daily and archival data is laudably available online, a lot of unnecessary barriers still exist to its use. Those could be quickly and cheaply addressed by listening better to the broader user community. On a positive note, Goddard GISS has made a really excellent effort to level the playing field on these clunky closed file formats, thanks especially to Robert Schmunk there. I installed their Panoply 3 software the other day to work with netCDF, HDF and GRIB (.nc, .nc4, .hdf, .hdf4, and .hdf5) for a regular Mac desktop. They provide Windows as well. Panoply not only opens the files but resolves a great many issues such display image jpg degradation, map projection changes, crummy palettes, masks, kmz and video output and the like. Wolfram's Mathematica from v6 on can also extract the array goodies and do about anything to them, but that costs something and has a substantial learning curve. Meanwhile Gimp is going all-GEGL and to higher bit depths, which will help us immensely on data degradation, poor contrast (white on white) situations and on massive processing tasks. Gimp 2.6.8 has a really sweet implementation of wavelet decomposition; I'll give a couple of examples shortly of how that illuminates the satellite resolution issue above.
Uh, knock on the door all you want, the problem is nobody's home: 1988 The first SSRI (selective serotonin reuptake inhibitor), Prozac, is made by Eli Lilly and launched in the US. 1989 The drug reaches the UK. It hit the covers of Newsweek and New York magazine, which described it as the "new wonder drug for depression". 1991-2001 Annual UK antidepressant prescriptions rise from 9m to 24m. 1994 Elizabeth Wurtzel's memoir Prozac Nation is published, establishing the drug's position in popular culture. 1994 The first of many lawsuits concerning side-effects of the drug goes to trial. Joseph Wesbeckerwent on a killing spree in 1989, killing eight before shooting himself. His violence was claimed to be a side-effect of taking Prozac. 1994 Psychiatrist Peter Breggin's Talking Back to Prozac, critical of the drug, is published. 1995 Prozac is referenced in the Blur song Country House: "He's reading Balzac and knocking back Prozac… It's the helping hand that makes you feel wonderfully bland." 1998 Prozac Diary, the candid memoir by Lauren Slater, is published. 2000 Zoloft overtakes Prozac as the most popular SSRI in the US. 2001 Prozac (fluoxetine) loses its patent. Eli Lilly loses $35m of its market value in one day and 90% of its prescriptions in a single year. 2004 Prozac is in our drinking water. The Environment Agency says the drug is building up in British rivers and ground-water supplies, probably via the sewage system, but in quantities so dilute they could have no effect. 2008 Antidepressants are now the third most common prescription drugs in the US. 2009 The Lancet ranks the top 12 antidepressants from 117 studies. Zoloft and Lexapro come in first for their combination of effectiveness and fewest side-effects. 2010 One in 10 people in Europe has now taken an antidepressant 2011, it was the second-most prescribed antidepressant on the U.S. retail market, with 37,208,000 prescriptions.
Toggle Commented Aug 15, 2013 on Perception of the Arctic 2 at Arctic Sea Ice
I think there is a fully satisfactory range of views repesented here already without including insincere posts. Trolls have no shortage of blog sites of their own where they are free to post without limit (but who is reading?). Trolls today play their cards close to the chest initially but the common denominator here seems to be jumping in immediately on new threads with the goal of souring them, followed a high volume of unconstructive posts and tiresome denialist argumentation. I favor cutting them off much earlier and deleting their entire post archive. One easy-on-the-administrator approach might be auto-limiting everyone to three posts per thread. True, someone could be defeat this with multiple avatar commenting software but we haven't seen that so far. Three posts gives everyone a shot at providing some resources and responding to misconceptions in previous posts while avoiding chat room discussions, squandering quota with empty posts, and thread re-directs.
That's right -- if it's persistently cloudy and the satellite is observing the ice at wavelengths that cannot effectively penetrate those particular types of clouds, then any and all secondary products derived from that imagery (such as area, extent, volume, melt pond, ice edge, drift, and thickness) cannot help but be erroneous. That's worth repeating so we don't have to go over this again: if the satellite is observing the ice at wavelengths that cannot effectively penetrate the cloud, every secondary product based on those wavelengths will be misled because the satellite did not actually provide it with any information about the sea ice patch under the cloud. No algorithm, no matter how clever, can make something out of nothing. However these tools operate in unattended pipeline mode, so that doesn't keep them from trying -- the day's product will be produced and put out on the server regardless. We currently have access to Arctic sea ice observed at 17 different wavelengths (3 visible, 6 infrared, 8 microwave) and 2 polarizations. The optical properties of clouds -- and cloud combinations -- vary annually, seasonally and daily. We basically have no information on the range of summer Arctic cloud types, their natural variability, persistent seasonal patterns or multi-year trends and so play catch-up at the end of melt season clearing. Everyone is comfortable interpreting familiar wavelengths such as Modis visible and can see when the satellite is getting down to the ice itself. However visible and IR wavelengths have the very worst summer cloud-penetrating capabilities and it's been a cloudy summer. At less familiar wavelengths, how do we distinguish actual satellite visualization of sea ice from overlying cloud artifacts? Here the intrinsic resolution of the satellite sensor may be fairly low, with passive emission at long wavelengths unable to resolve specific features in the ice such as cracks and individual floes. Because weather systems move through very rapidly compared to the slow drift of massive ice, short animation sequences unmask the clouds. When a given cloud type maintains a distinctive shape over several days, its adsorption, emission and solar reflectance spectra can be reconstructed from sampling it at the 17 wavelengths, with that outcome potentially useful in partly correcting ice products. However that is not happening with many of the secondary products because you can still see the clouds racing across the product. And you have to wonder about the ones where they aren't, especially in regions that have been impenetrable for weeks on end. Right now, I would say the most informative satellite products out there are the 6 Ghz descending horizontal polarization for anticipating end state of melt season and the 89 Ghz polarization ratio (August 2013 vs 2012 below).
Toggle Commented Aug 11, 2013 on ASI 2013 update 6: major slowdown at Arctic Sea Ice
Best observational thing going on land permafrost methane seems to be low elevation overflights by Carve. "The CARVE science team is busy analyzing data from its first full year of science flights. What they're finding, Miller said, is both amazing and potentially troubling. "Some of the methane and carbon dioxide concentrations we've measured have been large, and we're seeing very different patterns from what models suggest," Miller said. "We saw large, regional-scale episodic bursts of higher-than-normal carbon dioxide and methane in interior Alaska and across the North Slope during the spring thaw, and they lasted until after the fall refreeze. In July 2012 we saw methane levels over swamps in the Innoko Wilderness that were 650 parts per billion higher than normal background levels."
Toggle Commented Jul 27, 2013 on Arctic time bombs at Arctic Sea Ice
Along the lines of Kevin's comment, it's worth putting Wadham's actual response on the record here. "In support of your skepticism about methane emissions you quote authors who wrote before the enormous retreat of summer Arctic sea ice and its oceanographic effects became so evident. The mechanism which is causing the observed mass of rising methane plumes in the East Siberian Sea is itself unprecedented and hence it is not surprising that various climate scientists, none of them Arctic specialists, failed to spot it. What is actually happening is that the summer sea ice now retreats so far, and for so long each summer, that there is a substantial ice-free season over the Siberian shelf, sufficient for solar irradiance to warm the surface water by a significant amount – up to 7C according to satellite data. That warming extends the 50 m or so to the seabed because we are dealing with only a polar surface water layer here (over the shelves the Arctic Ocean structure is one-layer rather than three layers) and the surface warming is mixed down by wave-induced mixing because the extensive open water permits large fetches. So long as some ice persisted on the shelf, the water mass was held to about 0C in summer because any further heat content in the water column was used for melting the ice underside. But once the ice disappears, as it has done, the temperature of the water can rise significantly, and the heat content reaching the seabed can melt the frozen sediments at a rate that was never before possible." I won't examine the views the 'chief meteorologist' at Capital Weather Gang who has not a clue what a peer-reviewed scientific journal is. Tenney Naumer got a good comment in to the effect, if all else fails, just saying, hey if your priorities permit, maybe actually glance at the Shakhova papers.
Toggle Commented Jul 27, 2013 on Arctic time bombs at Arctic Sea Ice
Wayne writes, "I will pitch in to help Neven purchase High Resolution radarsat images on special occasions... North of Beaufort and by the Pole" Ok, how about you buy the first 2-3 and we will follow up with as many more as needed. The quality looks great! Devon Island, lower CAA (undated):
Toggle Commented Jul 27, 2013 on Arctic time bombs at Arctic Sea Ice
Ned writes "significantly less sea ice during the Holocene ... argue against the idea that near-future would lead to any large and abrupt release of methane " Prior to its gradual inundation by sea water (which continues to this day), land permafrost was frozen to very considerable depth during the last, long ice age. That cap, now under continental shelf water and still frozen, is completely impermeable to upward methane diffusion (except at faults and talik lake chimneys which are only now melting). Because inundating water was very cold and heat diffusion intrinsically very slow, warmer mid-Holocene episodes never entirely melted the cap and so methane accumulating under the cap (primarily from oil shale thermal decomposition in the case of ESAS) was never purged but instead continued to accummulate. Methane clathrate does not exist at depth because of the earth's geothermal gradient. The South Kara Sea methane article Steve B brought up has a good discussion for that region. Only the offshore cap past the 20 m contour has become permeable to date.
Toggle Commented Jul 26, 2013 on Arctic time bombs at Arctic Sea Ice
I would echo the concerns of Steve B above. That South Kara Sea methane full text was an easy and informative read that complemented related studies in the East Siberian and US and Canadian Beaufort Seas. It provided significant new data and better understanding of events beginning in the last marine transgression at 19 kyr, notably the longer exposures of deeper methane deposits and sediment sources to a radically warmer and thermally more conductive regime. Meanwhile, the Nature article did not lift a scientific finger towards assessing the methane factual situation. I didn't add a comment at the time Steve first brought it up. Waste of resources -- I know a great deal on the scientific side of methane and am willing to explain it -- but for the time involved, the background level of participant misunderstandings, the rapidity with which comments get buried, maybe 2-3 others following the commentary, and peak melt season hard upon us -- it couldn't be justified. Climate science mostly dodders along on its 2100 timeline -- folks still hiding their latest little papers on 1979-2006 ice pack behind paywalled journals, profe$$ional $ociety barriers and minimalist, rarely updated research group web sites -- whereas the mainstream publicaly funded sciences abandoned those practises years ago. Methane is never going to get a fair shake from scientists deeply -- and mistakenly -- invested in the carbon dioxide modeling culture and the self-imposed holy grail of land temperature sensitivity to its doubling, outdated, irrelevent and mis-placed agendas at this point (400 ppm). Yet that is almost entirely what the public hears about. What to do? -- we are in a situation here where maybe 1 person here in 20 has full-text access and perhaps 7-8 more have the stomach for them. However under fair use, those with access could quote enough that others would have an unimpeded view (which rarely would add up to a half dozen paragraphs and 1-2 figures). Sea ice is a done deal -- if not this year, then the next 1-2. So come October slackwater, maybe get serious on developing a methane resource with quality like that of the sea ice.
Toggle Commented Jul 26, 2013 on Arctic time bombs at Arctic Sea Ice
Here are the links to the most recent 7 day Modis reduced-cloud composite -- July 23 -- from Environment Canada. A remarkable change from the previous week: http://ice-glaces.ec.gc.ca/prods/MODISCOM-F/ http://ice-glaces.ec.gc.ca/prods/MODISCOM-T/
Toggle Commented Jul 25, 2013 on Second storm at Arctic Sea Ice
DanP continues his fantastic work over at the forum, constructing high resolution (4900 x 4900 pixels, 9 MB jpg named by first [of 8] days in the mosaic and band combination) cloud-free Modis imagery, which Articio is helpfully hosting with continuous zoom A lot of great information pops out from these white-on-white after a couple of quick (and reproducible) enhancements. It's going to be quite valuable to have an image after this storm clears. 932 pixels full width:
Toggle Commented Jul 25, 2013 on Second storm at Arctic Sea Ice
Kate writes, "the spiraling ice is going to be moving for days even after this finishes." The reversal in circulation over the last few days -- from CW to CCW -- represents a colossal and rather sudden transfer of momentum transfer from atmosphere to ice. Had the ice been going CCW before the storm, it would be rotating even faster today -- yet this effect may be offset by differential response to reversal, according to ice tensile strength variability.
Toggle Commented Jul 24, 2013 on Second storm at Arctic Sea Ice
The lower third of Big Berg broke off on 22 July 13 (according to cloud-penetrating microwave) and two days later the top third came apart as well. So it will be short-lived overall. Of more interest, is the impending disintegration of the land-fast ice to its northwest. Buttressing of the 79 glacier may disappear following that.
Toggle Commented Jul 24, 2013 on Ice pack in full at Arctic Sea Ice
Indeed, Doug, a reality check is timely. Melt ponds are (possibly low salinity) fresh water sitting over 1-2m ice; their temperature is therefore indistinguishable from 0ºC. As is adjacent still air -- with minimal heat capacity of its own -- equilibrated with them. I've always wondered how the '6m' temperature correlated with buoy *surface* air temperatures. Here of course we have a very windy day and turbulent air. DMI is showing -2 to -1ºC but off-center with respect to the low. The latter agrees quite well with Jaxa though there's considerable uncertainty in the latter's swath time.
Toggle Commented Jul 24, 2013 on Second storm at Arctic Sea Ice
Here's what Navy Hycom thinks about ice speed and drift for the next 7 days. The big days anticipated there are 27-29 July. Note the velocity vectors are rather dramatized and do not actually amount to much net movement. Today is the big day for Jaxa, our main microwave satellite -- the first year to year comparison will be available in about 9 hours. Let's just say 2013 is unfolding quite differently from 2012.
Toggle Commented Jul 24, 2013 on Second storm at Arctic Sea Ice