all them Arctic storms
Must be increasing ... did we not snooze through the winter season in years gone by?
The papers of Boisvert remain the best resource for individual storm impact analysis (such as the 27 Dec 15 colossus -- a couple of figures from that added below) and their historical occurrence, see #784 or her researchgate page but see also the new free full text Nature paper:
http://forum.arctic-sea-ice.net/index.php/topic,1611.msg94119/topicseen.html#msg94119http://www.nature.com/articles/srep39084 north pole meteorology
The N-ICE2015 also experienced six significant storms and documented them extensively. The Z Koenig 2016 article is out and the raw meteorological and oceanographic data have been released. These provide real data on shipside conditions unlike models or reanalysis. The storm/mixing figure from that is attached below. (First page, figures and captions are always available from Wiley even when the article is paywalled.)
Winter ocean-ice interactions under thin sea ice observed by iaoos 2016. DOI: 10.1002/2016JC012195
https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/157916 some 3D images.
Just following up on effects on Fram export of mid-latitude storms sweeping up past Svalbard/FJI, #1495.
One issue in using DMI is that they post Sentinel mosaics of different dates for a single date. These dates are not specified, nor are tiles tagged with their ESA identifier. For example, "Dec 19th" is actually a composite mostly of Dec 18th with a smidgeon of Dec 19th. Tile pieces can be re-used on multiple days and can be a mix of Sentinel 1A and 1B. Howat at OSU uses a much better system involving a simple 2-bit companion layer.
This practice at DMI is very problematic for feature movement tracking because the elapsed time between two scenes has been discarded. One day displacement could appear doubled if it were really two day displacement, halving the velocity (example shown below).
It is necessary then to go to
http://www.polarview.aq/arctic to find the underlying tiles as their file names contain these times both stamped irrevocably over the data but more conveniently in the urls (which can be subtracted in a spreadsheet after minor parsing, eg ... S1B_EW_GRDM_1SDH_20161218T100314_164F_N_1.jpg --> 2016 12 18 100314).
These Sentinel satellites are a revolutionary new resource for Arctic ice because the near-polar orbit results in almost
daily coverage of high latitudes around the central meridian (though far less for the Chukchi side). This plethora of imagery can totally swamp out the PolarView interface unless its 'custom date range' feature is used to step through individual days.
The very high resolution of Sentinel active radar (compared to passive microwave) is a mixed blessing in that full resolution file sizes are impractically large if the application is a time series feature tracking, say for movement, melt, ridging or fracturing.
In a normal field of science (like astronomy or biomedical genomics), users would simply draw a box and specify their date range and receive back a link to a compressed folder at Amazon AWS where the applicable areas of the applicable images would open as a co-registered stack in common open source software such as ImageJ.
If, like NeilT you've never done an ESA retrieval, you may have missed our previous extended discussion over at Jakobshavn of why the ESA site is such a mammoth time-waster. Here though someone took the initiative of re-posting it all on the cloud with a decent front end.
However it's still in that abandoned jp2 format without box restriction of field of view. We do not want all the whopper files that intersect some tiny corner of the box; we only want the data as cropped to the box. Again, as this involves decompression, array cropping to pixel corners and recompression, it is far better implemented once on the big computer side than thousands of times on the little computer side.
Do people really think that a field biologist, looking for safe ice to draw blood samples from a wild polar bear for chlordane, has the time or background to write python scripts? They're back on email basics, struggling to open attachments.
https://www.ncbi.nlm.nih.gov/pubmed/15093456https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1331997/The user community for satellite imagery is vastly broader than the original PI. Both AIRS (May 2002 launch on Aqua) and SMOS (Nov 2009) illustrate this. What's this about: 2378 spectral channels of infrared; soil moisture and sea salinity?
No design intent here to measure Arctic clouds or thin ice, yet we take a daily refresh with morning coffee as a given today, but research groups had to seriously pound on the data to get anything Arctic out of them. SMOS-Cryosat-AMSR2 ice partitioning is a major advance in nuanced inter-annual comparison and current freezing season status over ice vs not-ice.
The image below shows a marked-up area north of Greenland from the 20th December Sentinel. It was feasible to track displacements and rotations of the feature shown for about six weeks. This included several patches of stall followed by large Fram-ward lurches coinciding with storms.
Daily mean velocities can be deduced from displacement and timestamps. These are consistent across the image field (ie similar for features farther to the north, not shown). The shortest distance between Greenland and Svalbard being 434 km of which perhaps 200 km is occupied by ice being exported, allows total area (and ice volume) exported to be estimated over the 04-20 Dec 2016 time frame.
But how significant is this loss of older thicker ice in the larger scheme of things, can the effect of winter storms on melt season preconditioning be disentangled from manifestly large natural variations in Fram export, has there been a softening of viscoelastic parameters with thinning warmer ice altering storm effects on the ice pack, is not Atlantic Water bottom and frontal melt along the much longer Polar Front a more important consideration?
While a causal connection between these storms and an export pulse could probably be established, it's hard to say what would have happened in the absence of the storm. As Juan and wip have noted elsewhere, the notion of decomposition into climate + weather is increasingly elusive. Quite a few sites have dropped all mention of 'climate' and are just saying such-and-such was used here as baseline, take it or leave it.