2nd remarkable retreat front

~ Early Great Blue  gaining on sea ice not only for Beaufort sea

Sea ice loss North of Franz Josef lands  top,  more than 100 km between May 17 and May 29 2016, May 17 is the photo with less sea ice.
Courtesy NASA EOSDIS   The apparent Northwards expansion of the North Atlantic is really the
drift of the the entire sea ice pack towards Fram Strait (bottom left).  What is unusual may be judged by sea ice fluidity,
mobility or lack of cohesion,  entirely due to warmer temperatures and the collapse of thinner sea ice ,  usually the "glue" slowing or keeping the pack more consolidated.  This sort of movement always normally occurs in August or late July.


DMI 80 North data can thus be affected by necessarily warmer air gaining a greater area North of 80 degrees latitude:


This graph may indicate a larger colder area over the main pack,  the more open water changes the over all analysis.  It would be preferable to have a similar Graph covering surface temperatures 85 latitude Northwards.  WD May 29, 2016.

   Post news:

June 14 EOSDIS,  the 2nd melt front appears to have filled with loose pack sea ice spread out because temperatures have warmed much further. Consolidation lost,  sometimes extent values may give a false idea about current sea ice action.  Make no mistakes in judgement,  this is the greatest melt in history.  It comes with scattering of loose ice, from that point,  greater clouds are possible,  although not lasting because air temperatures are too warm.  WD June 14,2016

No sea ice horizon upwards rebound observed close to Midnight sun

~Optical Thermal observation method further explained,   proving Ti<=Ta
~Likely  24 hour bottom melt  earliest captured....

   Preceding article questioning NCAR  calculations can be seen here.  The sea ice Horizon would
drop below Astronomical Horizon (AH) if top of sea ice was warmer than surface air.  In many years of observations it was never observed doing that,  the much lower sea water horizon observations with colder than sst air were never repeated with ice.  Instead spring sea ice horizons maintain AH until evening or until under sea ice melting is 24 hours a day.   This likely happened yesterday,  South Cornwallis Island looking at westward MW Passage.

May 19 2014-2015-2016 Horizon comparisons (left center right).   2016 was taken 40 minutes later same date,  but with horizon at AH.  While 2014 and 15 rose above and kept on rising,  despite cloudy conditions, whiter streaks are breaks in clouds sun ray reflections.  The rising horizon 2014-15 was created by cooling of air accelerated by minima top of sea ice core temperature.
2016  core appears warmer,  if not significantly out of cooling potential.   

     On a given Arctic spring day, the horizon drops to AH when the air temperature Ta is equal to top of sea ice temperature Ti.  When reaching AH,  it is highly likely that the bottom of sea ice melts,
but during spring the AH horizon lasts a few minutes when it first shows, in March or early April,  so accretion keeps on making net gains.  AH horizons gradually become longer, but when AH is maintained more than 12 hours,  the bottom of sea ice melts more than forms,  net bottom melting occurs.   This has happened yesterday,  when AH was observed 1 hour before the midnight sun.  For the first time I have observed this in May,  this makes Spring 2016 fast ice the weakest heat resisting sea ice observed since 2010 when spring observations have started.

While taken at same evening time,  the same 19 May Ice horizon appeared at different altitudes.   2015 (left) kept rebounding upwards,  while 2016 remained steady so 1 hour prior the midnight sun.   Sea ice bottom accretion has stopped in 2016,  and now bottom daily melting has started.  

      These key observations capture the very thermal structures instantaneously.  Its all about sea ice temperatures affecting the air right above,  with of course radiation forcing,  when the sun gets through.  wd May 20,2016   

Optically unlikely not possible remote sensing/model? measurements/calculations

     85 to 90 N NOAA Reanalysis.  May 16, 2016.  Use the mouse pointer to compare surface and top of sea ice temperatures.

     There are several reasons why surface sea ice temperature can't be warmer than surface air. #1  It is optically not observable,  if there is a steep adiabatic profile from ground/ice  temperature to Surface air 2 meters above,  it would give an optical illusion,  similar to hot road mirages.   We have here on this example given many locations with a 2 degree C temperature difference between skin to surface air.  This would give a   lapse rate 100 times more than the normal 10 C/Km.     #2 Thermally improbable.  Top of sea ice temperature influences the surface air temperature,  if the air is colder than top of sea ice,  this is a very unstable thermal structure,  ice would cool rapidly by convection upwards of the air touching it.  While air warmer than sea ice invokes a normal stable thermal structure.    Because ice/snow surface is white,  especially since thermal conduction from lower in the column sea ice is much greater than air to top of ice, air conduction affects top of sea ice less than colder sea ice column core minima,  very necessarily  at this time of late spring.  #3 clouds.  Likely covering 85N to the Pole here,  clouds offer a more neutral thermal flux balance,  whereas there is a steady equal heat flux up and down at the surface to air interface.  The net result is more of an isotherm,  but still slightly favoring the stable thermal structure,  which is colder top of sea ice than surface air.  WD May  19, 2016

Remote sensing VS Refraction Prime sea ice rule. Satellites are pretty good, but refraction observations are better.

~Ta>=Ti  rule holds well as seen from space
~ Is likely some remote sensing calculations/methods need some adjustments.

      Taking advantage of persistent "Big Blue"  of 2016 spring,  a truly remarkable insolation bombardment ,  the right term "relentless" onslaught of sunshine,  we can check and find if refraction gained insights (written here) are true on a planetary scale.    NOAA daily climate composites are very good,  so we look at its sea surface temperature setting or "surface skin" temperatures VS surface temperatures.


        NOAA May 4 2016.     Daily mean surface temperatures  "1000 mb" temperatures are too cold in East Siberian and North Barents seas,  North of Ellesmere and Greenland surface air 1000 mb is largely too cold.  There is a strange North of Wrangel Island surface air cold area spot and also compared to entire Chukchi Sea surface temperatures.  Basically if I am correct,  Remote Sensing surface temps algorithms daily means appear to have a mixing problem with land features.    Note Surface temperature  1000 mb Ta is indeed always warmer than top of ice Ti well away from land.

      Click on GIF image to expand and use your mouse pointer to make comparisons.

     If there is a calculation error with NOAA surface temperatures,  it would be "averaged out"  eventually because Ta>=Ti ,  a fact gained by multiple horizon observations,  this feature will show up over a longer term:


           NOAA  May 1-5 2016.  Composite mean makes it much harder to find Surface air 1000 mb air colder than top of sea ice.    The North of Wrangel Island temperature anomaly most likely was from thicker sea ice pressure height temperature difference.  Although,  North Barents Sea has still a smaller area of colder air especially East of Franz Josef Islands.

      Hypothetically,  the longer we average out the  likely Algorithm  error,  the more impossible it would be to find Ta < Ti.

               March 1 to May 5 2016,  literally impossible to find top of sea ice temperature
warmer than  surface air 1000 mb temperature.


   NOAA surface temperature looks better but still has small daily flaws.  

    

           May 9, 2016  NOAA daily composites offer surface air temperature feature which performs slightly better than 1000 mb,  if you click on extreme cold surface air temperature near land it will be likely erroneous, making surface air colder than ice.    Which has never been observed optically.


      Likewise looking back longer term:



            April 9-May 9 average   If you find a spot where Ta< Ti  ,  let me know.   There are none I can find.


    In short:

         NOAA remote sensing temperatures are quite good,  but I would look at every case when
sea ice is warmer than surface air,  double check the calculations and the physics.  I don't know if this is the error which causes sea ice models to err in making good melt projections.  A  4 C warmer sea ice  than surface temperature (Chukchi anomaly very top GIF above) would make the horizon extremely low and that has never been observed, on top of the underlying thermal physics which would be hard to explain.  WD May 7 and May 11, 2016