Varying thermal fluxes as portrayed by sea ice horizons.

~A few examples.
~Clouds help discern 2 distinct albedo reactions.

  At stake is this graph done by very capable mathematician Tamino,  essentially portraying total sky albedos given various weather possibilities:

   At latitude 75 degrees North we will deal with zenith angles  70 to 90 degrees.  Essentially the 2
blue lines.   Knowing Tamino's thorough laser dedication to exactitude,  this graph likely represents the standard  widely used Albedo reference numbers.   Note the "clear sky over bright sea ice"  vs "cloud over bright sea ice"  small 10% difference.  We deal here with these 2 features.  Keep in mind the actual horizontal view largely contradicts this.  If there is albedo reflecting clouds at Local Apparent Noon, the horizon view is dramatically different than with "clear sky albedo" consistently and repeatedly,  incoming sun rays become very deflected,  leaving a dramatic difference in horizon heights, either at Local Apparent Noon  or especially seen easier later as the sun lowers to the horizon.  A complete cloud cover  leaves the horizon altitude in a steady state of flux, as opposed to "clear sky albedo"  which enables the observer to witness various thermal effects un-impeded.  This implies that back radiation from bottom of clouds leave sea ice in neither extremes of cooling or warming.  Therefore heat which could be gained from direct sunshine is lost.  During the dark Arctic long night, clouds do just the opposite,  a lot of heat is not lost to space,  while during the long Arctic midnight sun days, persistent strong albedo clouds prevent a great deal of melting.

      The integrated albedos (graph above) perspective may be an erroneous concept.  Albedo layers  should  be calculated individually layer by layer following the sun ray path.  The idea of merging albedo layers is good, but 50% seems too low given the greater cloud cover when sea ice cools the warming summer surface.

   During the Arctic sea ice melt season there can be up to 4 stratocumulus decks stacked on top of each other.  It is the most common Arctic cloud,  with small water droplets 10 micrometers in diameter, there is also often wide ranging fog banks becoming stratus and reverting back to fog in long lasting cycles. Summer time viewing of sea ice from the vantage point of High Resolution satellite pictures is almost always a tasking job:

"Cloud albedo varies from less than 10% to more than 90% and depends on drop sizes, liquid water or ice content, thickness of the cloud, and the sun's zenith angle. The smaller the drops and the greater the liquid water content, the greater the cloud albedo, if all other factors are the same.

Low, thick clouds (such as stratocumulus) primarily reflect incoming solar radiation, causing it to have a high albedo, whereas high, thin clouds (such as Cirrus) tend to transmit it to the surface but then trap outgoing infrared radiation, causing it to have low albedo. It contributes to the greenhouse effect.[1][2]" wikipedia

       The presence of extensive multi layered cloud spreads,  often covering the entire Arctic Ocean for weeks, certainly brings up the cloud albedo value well above the 50% mark.  On occasions,  such as during summer 2007,   with persistent anticyclones, next to land and moving northwards,  shatter clouds important ice protective vail,  plummeting the ice pack to melt rapidly.  

    One primary reference for 50% integrated albedo was the Sheba project,  although the vanishing albedo is correct interpretation of latest melt trends, the nature of sea ice albedo is less variable than cloud cover. 

An annual cycle of Arctic surface cloud forcing at SHEBA , JOURNAL OF GEOPHYSICAL RESEARCH: SUBMITTED JANUARY 19, 2001 

   Sheba Albedo graph has been cited in other journals namely:  http://www.pnas.org/content/111/9/3322.full

   While the data proved interesting,  the said research ship location in summer 1998, Beaufort Chukchi seas, which by coincidence marked the beginning of the greater melting summers to come: 

       The open water footprint amongst sea ice at minima in 1998 suggests there was a great deal of insolation leaving mostly atmospheric absorption and sea ice albedo to reduce the melt otherwise with the full force of nearly direct sunlight and of course lesser total albedo.   

Calculation using separate step by step not integrated albedos:

Entire Arctic ice melt calculation using best albedo data available separately,  suggests a correct interpretation of the physics,  in a simple equation I call ASIMP,  Arctic Sea Ice Melt Potential

   ASIMP = Area of entire Arctic Ocean X TOA TSI  for Arctic Ocean  6 months from spring equinox to fall equinox X average summer sea ice albedo X Atmospheric Absorption factor X Average cloud albedo  / sea ice latent heat of fusion.

Using 

Arctic Ocean sea ice area:  14E6 km2 
Top Of Atmosphere average TSI for same area for Equinox to Equinox 70 to 90 N=  257 247 W/m2
  (equinox calculation closely matching known TSI graph median)
Clear Sky Albedo (sea ice albedo) =  50%
Atmospheric Absorption = 23%
Average cloud albedo over the summer = 80 % 
(1) Sea ice latent heat of fusion =   2.95e17 j/km3   U.N. fisheries and agriculture department
  (with density 0.89 t/m3 U.N, 1% salinity at -2 C according to Doctor Ono's chart)

     Gives ASIMP = 15,081 km3 (calculated mar 7, 2017) close to the actual POMAS latest summer melt 17,500 km3.   (77% cloud albedo is needed to make  ASIMP equal to 2016 summer melt). These variables were at first taken from different sources, I did not try to fit with known melts,  and they need be perfected, leaving the greatest yearly variation to cloud albedo.    This reformulation calculation gives a fairly interesting estimate.  

----------Arctic "clear sky albedo" vs cloud albedo effects:

   Series pictures displaying different sky conditions and resulting thermal flux action at the sea ice horizon.  If horizon outgoing thermal heat is equal to incoming Astronomical Horizon is achieved.
All pictures mostly above A.H. indicating net thermal loss from the sea,  those at A.H.  will be indicated.   None can be below A.H,.

   On all pictures,  top left:  date time, top right:  general sky condition,  lower left: temperature wind speed with narration, lower right: sea ice horizon elevation (2.6' is astronomical horizon) below is sun elevation in degrees.

     Dominant  Low cloud albedo

     Clear Air Albedo

     Arctic Ice Fog

   Mixed albedos , warmed sea ice

   Clear sky , warmed sea ice

    Clear sky albedo, sea ice "wall"  , maximum horizon height boosts, large diurnal thermal variations

     Clear sky albedo

   Horizon low clouds,  mixed albedo, clear at camera, cloudy away above sun beam path

    Clear sky albedo with some distant mid day dissipating later ice fog 

   Clear sky albedo , mid day distant ice fog and clouds

Mostly cloud albedo with light snow

Clear sky albedo,  all sea ice albedo.  

Clear sky albedo, all sea ice albedo

Early fog then cloudy albedo

 More to come...

Summer greater cloudiness thermal flux mystery resolved

~Has huge implications with respect to sea ice melt season.
~ Partial cloud cover reduces sea ice albedo,  this was captured by horizon refraction method.

"Spectral albedo and transmittance of thin young Arctic sea ice "

by

Torbjørn Taskjelle1, Stephen R. Hudson2, Mats A. Granskog2, Marcel Nicolaus3, Ruibo Lei4, Sebastian Gerland2, Jakob J. Stamnes1, and Børge Hamre1 1

at

http://onlinelibrary.wiley.com/doi/10.1002/2015JC011254/abstract

 A most interesting paper,  well apt study with respect to greater current thinner sea ice conditions, has made at least 2 major discoveries:  

15 cm sea ice has :

"Integrated albedo and transmittance for photosynthetically active radiation (400–900 nm) were in the range 0.17–0.21 and 0.77– 0.86, respectively. The average albedo and transmittance of the total solar radiation energy were 0.16 and 0.51, respectively. V"

     That is a rather big discovery-observation,  it means that thin sea ice even with a bit of snow has 4 to 4.5 times less albedo than thicker ice,  likely in excess of 1 meters thickness.  

   The rather much larger discovery:

"Under a cloudy sky we found molecular oxygen absorption bands in the atmosphere to favor light traveling less obliquely and thus slightly increase the fraction of light penetrating the ice within these bands compared to the penetration of light at wavelengths outside the bands. For large solar zenith angles, a cloud layer was found to increase the ice transmittance at all wavelengths, because it shifts the average direction of the light toward the vertical."

This very important observation/conclusion solves a once puzzling Horizon Refraction mystery

found in the High Arctic Nunavut Canada:

All these spring April to May 2011 horizon sequences,  one day per row, from shortly after Local Apparent Noon towards end of Arctic day till sunset,   have one thing in common,  clear skies and rising horizon from afternoon to evening.  This is explained by sea ice approximately 1.5 meters thick mostly covered with snow 10-20 cm,  stretching all the way well beyond the horizon line, and the lowering sun as evening progressed.  Transmittance of solar energy,  said to be much reduced by albedo as much as 90%,  with only 10% transmittance of short wave sunlight.  

       However weakened by the very sun ray reflectiveness of sea ice and snow cover,  the surface of sea ice temperature became equal to surface air after Local Apparent Noon,  with Astronomical Horizon held as long as the sun further warmed the ice.  Then after,  as the sun elevation lowered,  the surface of sea ice and snow cooled along with air interface by conduction,   while the air immediately above (a few meters above the surface to air interface) remained warmer, this caused surface inversions becoming steeper as the sun descended further.  We can judge the thickness of sea ice by the horizon rebound height.  From April (top sequence) to May (bottom) the ice thickened,  hence by conduction,  the mid or coldest layer of sea ice  embedded within its column cooled the top of sea ice quicker than the rate of cooling of air having a much lower heat capacity.

These observations are a constant feature unless clouds (sometimes winds) play havoc with the thermal fluxes: 

May 17 2011.  a fine sunny noon Astronomical Horizon (extreme left) ,  yet the horizon line largely stayed steady afterwards,  because low clouds covered sky thereafter.  One reason for the steady horizon, Taskjelle, T., S. R. Hudson et all suggest that the albedo of sea ice itself may be weakened by sun rays hitting the ice more perpendicularly,  the other explanation is the well known  lessening of energy escaping to space,  long wave radiation bouncing back and forth from cloud bottom to top of sea ice.   The former implies a neat possibility of extra but slight transmittance gain of energy to sea ice by albedo change,  combined with clouds causing a lack of surface cooling,  confirmed by the multitude of persistent near Astronomical  Horizon height horizons observed,  which of course means a significant drop or cancellation of sea ice accretion.  

And so on May 2 , 2011 the horizon height never changed at all,  this despite the clouded sun 30.8 degrees elevation (left) giving the same energy or horizon thermal flux result as when the still covered sun was 10.81 degrees elevation later in the evening.  This seem to contradict basic thermal evaluations until we consider that the light getting through the later evening cloud horizon gap  (right) has had an impact,  reducing the cooling if not slightly increasing the net warming,  because the sea ice albedo changed from more vertically directed photons hitting the icy/snowy surface.  This kind of late evening horizon observation was not at all rare.  

 Conclusion and also in appreciation:

     A strange phenomena was perceived throughout many evening horizon refraction observations,  in Southwest Cornwallis Island,  Nunavut Canada,  there was a lesser rise of horizon,  no change in height or even a drop in horizon heights,  unexplained by any other mean but an assumption that the distant horizon had different weather.  

         But a paper written by Taskjelle, T., S. R. Hudson et all  revealed a likely change in albedo of sea ice increasing transmittance of thermal rays reflected by clouds redirecting the rays at a lesser zenith angle.  This explains a couple of very interesting horizon refraction observations,  namely when cloudy there is definitely a greater thermal transfer to sea ice because of cloud cover,  but also in addition by the reflection of rays at a lower zenith angle (higher horizon elevation) .  The two,  cloud cover and more direct ray bombardment of sea ice explains the lower sea ice horizon when cloudy,  and especially when partially cloudy.  Horizon refraction observations shortly after local apparent noon during fully sunny skies have similar horizon heights than when cloudy (usually lowest during clear air).  With overcast conditions towards sunset time, the lack of horizon rise as always observed with clear air,  suggests more energy towards sea ice despite a lower sun elevation.  However, there is more energy transferred to sea ice, lesser escaping it,  when cloudy,  this has a huge over all accretion/melting  impact needed to be considered.  

          The over all melting of 2016 Arctic sea ice,  2nd place in extent,  surprised many considering the greater cloudiness by persistent  Cyclones during much of June and July,   sometimes not so opaque,  which I called "see through".   More vertical redirection of sun rays usually low most times during the Arctic horizon summer may indeed give more melting than calculated.   

      Finally the effect of lowering horizon with partially cloudy  skies when nearing sunset time should have a Norwegian name given the discovery of reduction albedo as discovered by Taskjelle, T., S. R. Hudson et all...   

      WDFebruary 19, 2017

  

           

Unprecedented fluid leads near the North Pole, stunning images of never seen sea ice in such a poor state.

February 11 2017

A day to remember,  the North Pole area has sea ice nearly identical at peak melts during late summers  of a few years ago.   

Baffin Island,

to its East Baffin Bay,  West Fox basin,    the sea ice of these seas are usually fluid even during coldest years,  but it is very badly broken, with readily visible from space mega leads.  This is not so rare but uncommon.  It's been a significantly warmer winter than usual, like everywhere else in the Northern Hemisphere.   

Near the North Pole same NOAA HRPT 0908 UTC.

This is likely the first time when sea ice is so broken, fluid, and warm,  really by the warmest winter in Arctic Ocean History.  Sea ice is like a graph,  it records the cumulative temperature of winter by  exhibiting how "white" the ice shows on infrared Imagery,  the only brilliant white here is on top of Greenland or very high clouds.  Near Pole temperatures are easily 15 to +20 C above normal.  The intense black is set to -10 C or warmer.

  These leads from Pole to Atlantic,  I have never seen anything like this before  during the long Arctic night.   The last time I've studied anything similar  was during sunny summer,  not from long ago,  but from end of summers of the last 5 years.  Truly novel,  presage,  the ice is very fluid, in its worse shape in recorded history,  as I wrote a few years back, Baffin Bay will the model for Arctic Ocean sea ice, well,  that forecast has come through during winter,  will it do the same as Baffin Bay sea ice does this September? WD February 11, 2017

February 12 0532 UTC,  vast fields of leads extends from all sides of the North Pole.
Note in particular the Canadian Greenlandic side  once the last area of thick older sea ice. WD February 12,2017

     February 16, 2017,  NOAA 01:17:10 ir,  amazing display of many leads not particularly organized with the tide (in the past the only thing really breaking up thick sea ice regularly)  Interspersed and formed by wind/current/tide actions a feature of thinner sea ice.  The black leads of open water inject up to 400 watt/m2 sensible heat,  the coming cyclones cover the sky and shield this heat loss from escaping to space.  WD Feb 15, 2017

New World Weather Order (NWWO) blankets NYC and Boston

~The atmosphere of NE USA was much colder than Northern Greenland and Ellesmere
~CTNP cell moved South met a passing Northeast'ner

   CMC February 9 2017 surface analysis 1800 UTC, markings 700 mb and 250 mb 1200 UTC.   CTNP's of North America,  2 Vortices of the Arctic Polar Vortex,  are new and old,  the new one just started over Northern Alaska and Yukon,.  The few days in age older one now hovering over Hudson Bay with coldest spot Ungava Quebec,  this one moved South affecting the jet stream in blue,  having a collision course with an Atlantic cyclone winter storm Niko,   Most people way South over there in NE US had several recent Cyclones pass by,  but none gave this massive snow cover because of mild winter.    But just one  of the Polar Vortex vortices,  caused havoc.  I've marked in red 250 mb wind directions making a nice vortex around Hudson Bay,  in green is the 700 mb  -20 C isotherm.   Northern Ellesmere 700 mb temperature was -15 C,  700 mb is close to 600 mb a pressure height  close to where the average temperature of the entire troposphere may be found.  For those unfamiliar with Ellesmere Island Canada North Coast,  it is 2520 nautical miles straight Northwards   from NYC, traditionally where usually the coldest temperatures in the Northern hemisphere may be found at this time of the year.    As written on my previous article  smaller vortices of the Polar Vortex tend to move quite rapidly,  therefore  this winter pretty much represents many coming years cold seasons,  warmer but sudden much colder harsh snowstorms,  and back to mild winter,  back and forth unstable weather.  A New World Weather Order. WD February 9, 2017

Smaller southwards bound Cold Temperature North Pole Vortex bends Jet Stream Northwards

~There is a windy reason why very cold air matters.

~Apparent single  near North Pole -30 C 700 mb cold zone in the entire Polar vortex not typical.

   CMC February 8, 2017 700 and 250 mb chart,  the 700 mb chart identifies the coldest zones,  where the atmosphere is densest and influences Global Circulation. On the Russian side, the coldest air is beyond the limits of this map further Southwards (at about -25 C at center).    The 250 mb chart (with blue arrows),   highlights the jet stream,  a segment of which is very unusually to the West of North Greenland.  The coldest air of this world,  I call it the Cold Temperature North Pole (CTNP),  is hovering over center of the Arctic Archipelago, 2 more vortices,  one over Newfoundland the other South Central Russia,  represent tonights outlook of the entire Polar Vortex.  Note the counterclockwise circulation around the 700 mb coldest air zones  (close enough to 600 mb, which is the approximate mean height representing the average temperature of the entire troposphere).    The Newfoundland one is steering the jet Stream Northwards as well,  as we know,  yet another Atlantic big Cyclone will penetrate the Arctic Ocean but for these reasons in a few days.  The coldest air zones are smaller,  usually to the South of where they use to hang out.  Contrast this with an imagined  huge 600 mb cold zone,  spanning from Alaska to Greenland,   the Jet would steer further Eastwards not Northwards.  The smaller densest cold atmosphere vortices affect the weather to be wilder near them as well. A huge CTNP area,  as common in the past,  made weather fluctuate less, because smaller CTNP's move about quite a lot.  WD February 8,2017

Barely familiar Arctic sea ice.

~Only lately does one segment of the pack look a bit normal.

   December 17 2016  to January 27 2017 NOAA ir HRPT .   The last picture in the animation sequence, January 27,  has the only recognizable feature North of Ellesmere Island,  long Tidal leads not quite the same as 20 years ago or so.  The round ring between Northeastern Ellesmere and Northwestern Greenland showed up at times as well.  What is abnormal is Smith Sound floe edge very fluid  sea ice moving with the current and dominant wind,  North to South,  many marine wildlife depend on that area especially East of Jones Sound (extreme Southeast Ellesmere Island).  We can see a strong current from barely frozen fluid ice moving in Barrow Strait  to Lancaster Sound  ending up still very swift Eastwards to North Baffin Bay.   Kennedy to Nares Strait never froze as well.  The biggest change is the lack of deep freezing North of Ellesmere Island, this area usually can have temperatures as low as -55 C.     Infrared 'white signature zone can be recognized at times,   mainly Southwest of where it should be,  this location change is quite significant.   North of Ellesmere had a faint start of cooling mid December from the presence of a High,  but it did not last.  Pervasive clouds made selecting fewer pictures,  this is not the regular long night view,   clouds rarefy with the drying process of radiation escaping to space in darkness without sunlight replenishing heat.    Throughout this GIF sequence, Arctic Ocean pack ice leads direction features changed rapidly with the winds,  indicating the presence of thinner sea ice and more open water The area North of Ellesmere Island is known having the densest-thickest most stable ice history,  this is the area to watch,  the ring between Northern Ellesmere and Greenland usually should vanish slowly while remaining in place,  what we observe here is its destruction by fluid ice movement.  30 years ago,   just off Northwest Greenland sea ice buoys remained immobile throughout the winter season. WD January 28,2017

Blue Venus oracles.

~Amazing sequence reveals strong warming after 2 months of 2017 long night.

For the record,  Venus-set January 14 2017,  South of Cornwallis Island Nunavut Canada.    Top of a hill 2 degrees elevation high from the altitude of the camera,  the brighter colorful picture shows 2 important features,  one is dispersion of colors according to refraction laws,  red is refracted less than other optical wavelengths,  green much more.     The second yellow-red picture occurred just before Venus-set,  the colors are truer,  there is less overexposure.  The 3rd in faint blue is a Venus blue flash,  when the planet light beam is behind the top of the hill,  the upper most smallest segment of blue,  the color refracted most,   was carried last bent foremost in a narrow air duct.  Compared to same location top of same hill previous sunsets,   4 Venus-sets happened with the least refraction.  This was caused  by a warmer hill top reducing the inversion lapse rate,  despite very cold air temperatures,  the coldest of winter so far,  which arrived about a day and a half before.  The hill was warmed substantially by the lack of  wide open clear air,  following incredible persistent cloud coverage.  When this sequence was taken,  mainly clear air lasted for a few days.  WD January 25, 2017

Arctic Atmosphere is not the only thing with higher temperatures

~Latest state of art refraction work demonstrates land and sea ice  abnormally warmer.

  January18,2016.  Sea ice horizon in darkness,  a perfect way to study radiation fluxes.  2015-16 was a warm winter,  it had thinner sea ice,  but more snow , 40 cm,  a proxy for sea ice making it thinner.  warmth and snow made sea ice more than 30 cm below sea average.  

    To make out the meaning of the latest results we must study the over all  circulation picture courtesy NCEP/NCAR , the following are model maps of 600 mb temperatures,  at about this altitude we can determine the temperature of the entire troposphere which varies from one geographic point to another.  I find these maps helpful,  but we must keep in mind that there are no upper stations over the Arctic Ocean.

Super melt years, circulation axis of the long nights 2006-2007,  2011-2012 and 2015-2016 had one thing in common; they were SouthEast-North Pole-SouthEast Russian side,  the transpolar Southeast Axis.  The Polar Vortex  morphology was shaped favoring a very warm NW Europe and North America.  And it was.  

   Thinner sea ice circulations:  We remember 2013 melt season;  like one large Cyclone throughout the summer.  2016-17 long night circulation was Longitude 90 Degrees-North Pole- Longitude 90 degrees Russian side extending longitudinally Eastwards , an "L" shape .   Mean Vortices of the Polar vortex locations of 2013 were split in 3,  The winds rotate counterclockwise around the coldest air, the Blue zones.  This 2013  circulation pattern favored a much colder Eurasia,  mildly colder western North America. In 2016-17,  the vortices have migrated Southwards,  a reflection of thinner sea ice during winter,  the average here for North American sector does not represent this well for this sector.  With this Polar Vortex pattern,  NW Europe has a larger input of Cyclones from the Atlantic, more snow for the Northern Eurasian region,  unlike last winter these Lows tended to crash towards Novaya Zemlya which made for greater precipitation in that  quadrant.  A strong vortex (not seen here) hovering about the  Canadian Archipelago, in particular West Greenland Disko Island,  helped pull Cyclones towards the Pole.    As a result, 2016-17 circulation for the Canadian Archipelago has had far less snow than last year.   The snow maps indicate a great layering  from Pacific moisture East  of the Siberian Vortex,  the coldest of the season so far.  

 The average Low Pressure footprint from the North Atlantic 2016-2017 dark season so far.  The zones with Higher pressure were over the continents where the greater cooling took place.

   Last season 2015-2016 had lower pressure average North of Ellesmere.  North Atlantic  Cyclones died there, now they are attracted or steered by the greatest of the Polar vortex vortices, the Siberian one.   But the Arctic Ocean laced with water,  much thinner ice,  "attracts" Low pressure systems just as much as last winter.    Some linger and die over the Pole,  while they do,  the clouds outright warm everything to huge anomalous temperature gains.  From greater open water/thinner sea ice heat flux  the Lows die slower,  while they do, they "invite" other Northward Lows to replace them,  because the shaping of the jet stream is to the North mainly over the Gulf Stream,  a huge steady source of moisture.  The smaller vortex of the the Polar Vortex vortices,  was mainly centered over Baffin Bay,  although migrated North or South from that location.  This heavily shaped the North Atlantic Jet Stream to bend Northwards.
 
Warming of the entire Arctic recorded by optical method:


    The continuous onslaught of Cyclones Northwards along with the much more open sea water and thinner sea ice had a huge unprecedented effect on the atmosphere, land and frozen or open seas:

November 2 2016,   the sun has about vanished,  no more solar warming, new sea ice just formed,   late once again,  cools the atmosphere further by insulating the ocean.  This caused the horizon to rise,  since the lower atmospheric air is still warm, but the sea ice to air interface,  very colder.  

We look back 2016, January 23,  with -36.1 C surface temperature, in darkness and even if this was colder,  during a remarkably warmer winter,  interspersed by cooling and at least 5 important "heat wave" periods.  There was a lot of snow, twice the usual normal.  Despite all this,  the horizon rose 5.25 arc minutes higher than to November 2, 2016.  Still in total darkness, the sun didn't rise for another 2 weeks. 

January 19 2017,  it has been seasonably colder -33 C for about 4 days with a peak dip nearing -40 C,  a departure from overall much warmer winter.  The sea ice horizon from November 2 past, rose 3.5' of arc,  a significant drop in height during total darkness compared to last year.  A lowered horizon is always characterized by a lesser temperature contrast at the surface to air interface,  this latest observation is a strong indication of more heat on the surface which warmed cold clear air more than last year. The best way to explain this is 2  blocks of equal volume of identical matter, one at higher temperature,  the other at air temperature, the immediate impact of the warmer block would be to raise the temperature of the air next to it.  Likewise,  after months of mostly cloudier High Arctic weather,  effectively reducing thermal radiation escaping to space,  along with greater heat injected by open water and thinner sea ice,   the land and sea ice has a net warmer presence,  this translates in a lesser temperature contrast reducing horizon heights.  

     Just at the clearing of clouds,  a few days prior,  the data was even more compelling:

   January 14, 2017, a day after the persistent clouds cleared,  it was -37.1 C, a near 20 C drop in temperature occurred,  at this point, the horizon was 1.84 arc minutes above the November 2 2016 just freshly made new sea ice.  This basically demonstrated the long night cooling slowed substantially,  late in dark season ground surfaces offered a lot of residual heat reducing interface cooling.  The net refraction difference in altitude gain was a very significant -3.41 arc minutes between 2016 and 2017.  This is without interference from winds ,  clouds and with similar seasonal colder temperatures.  To confirm this pervasive warming,  a few hours later,  planet Venus set over a hill:

     A Venus blue flash indicated its last moment before disappearing below a 200 meter Above Sea Level hill 3.5 km distant from the telescope.  This hill is largely made of gravel on top of a interglacial rebounding limestone from the Paleozoic era.   The blue flash contrasts well with similar blue flashes ending of sunsets at the same location which occurred in the past late February's.  The hill sunsets altitudes were averaged compared to 4 Venus sets in total from January 10, 11, 12 and 14 2017.   The Venus sets disappeared at a higher altitude than sunset upper limbs by 1 to 2 arc minutes.  A staggering difference!  Especially at 2 degrees altitude,  the top of the hill was demonstrably warmer than the sea ice.  Even more impressive,  the Venus sets were from a continuous total 2 month long darkness,   proved the current  hill top surface to air interface lapse rate weaker than with sea ice,  no small event given the elevation height which naturally reduces refraction variances....

      South of Cornwallis land ,  air, ocean and sea ice,  all where measured warmer than usual,   the exact impact of such geophysics so late in the long night can only make the coming weather days predictively warmer. WD January 20, 2017

Thinner sea ice adds a whole lot of heat to the dark Arctic Ocean lower atmosphere, changing its circulation.

A paper published in 1996 by Steffen and DeMaria:

http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450(1996)035%3C2067:SEFOAW%3E2.0.CO;2

after measuring Heat fluxes over Barrow Strait  Nunavut Canada within sea ice and upwards in 1980, this paper basically demonstrates how much energy can be unleashed if the sea ice becomes thinner,  in effect about 4 times more heat is dissipated to the atmosphere if sea ice is 32 cm instead of 1.1 meters thick. 

It is the mark of thin Ice to give off more sensible heat.  By conduction and convection at the surface to air interface.    Thus it was November 1980 just South of Cornwallis Island.  Refraction wise, this is seen by a lower horizon.  An impressive mean of 129 W/m2 dissipates upwards.

Radiative heat flux takes over as the main dissipation thermal system as sea ice became thicker,  now some 1.1 meters,  3 months worth of pre 1998 normal cold during the long night of 1980-81.  Insulation from accretion makes it so.   But only 36 W/m2 towards space,  drastically less than 3 months earlier.   All the data from this paper mainly was but in pure darkness  with very low negligible sunlight in February and November.

When the lower Arctic troposphere warms, the entire Upper air profile changes.  So is the natural way of Atmospheric Physics: 

Average Monthly Upper Air Maxima altitude in meters 2011-2015
Southwest Barrow Island.

The height of Upper Air Profile Maxima  increases during winter, reaches a peak by February, then  becomes gradually lower towards the long day until vanishing during summer.    As the Maxima lowers in altitude ,  the surface to air interface upper air lapse rate does the same, it lowers in stability:

North Barrow Strait,  Southwest Cornwallis Island 2011-2015 average surface to air interface Lapse rates per month, excluding June July August,  in degrees C per100 meters

A February +5.4 C/100 meter lapse rate is super stable as opposed to -1 C/100 meters in early summer which is the normal adiabatic lapse rate of the standard atmosphere: 10 C/km.    Very latest data suggests a leaning towards adiabatic lower temperature profile, opposite to winter building up.  A higher temperature profile maxima altitude makes for a steeper surface based inversion because the atmospheric heat source is more distant from the surface.  Steeper inversions cause greater refraction effects which have been extremely rare compared to the same dark season periods going back as recently as the last 2 years. This suggests enormous current heat injections.  

Arctic summer natural effects from no sea ice gives the turning of the extreme  lower troposphere temperature profile from inversions to adiabatic.   In the graph above,  adiabatic lapse rates predominate  between May and September,  during these high in the sky sun days,  air temperatures decrease with height from just off the ground.  For other months; January to April, October to December the lapse rates are positive,  because just above the ground air warms with height instead,   until  becoming adiabatic again till the tropopause, at the altitude where inversion turns adiabatic is the temperature profile maximum.  Surface based Arctic inversions dominate throughout Arctic late Autumn , Winter,  till late Spring.  It is a sign of winter, when
frozen ground and sea ice in darkness radiate heat upwards with air, thermal radiation eventually escapes to space during cloud free nights,  the Arctic having one long night in particular, these inversions are nearly absolutely permanent for 9 months of the year. But lately these common inversions have been reversed to adiabatic profiles,  in deep mid winter darkness,  the amount of heat energy needed requires warmth from the sea.

The impact of less mid-winter sea ice thus cancels the inversion nature of the lower atmosphere.  Once nullified, the temperature profile becomes isothermal or adiabatic again.  As what was happening during the last few days near the North Pole,  in extended darkness,  heat exchanged between open ocean or thinner sea ice to Arctic air, simply enormous,  boosted and sustained from persistent warmer Cyclones,  exacerbating the ongoing positive circulation feedback of the entire Arctic Atmosphere, even more pronounced.  As the lower upper air maintains a Cyclonic nature rather than being laced with  lower inversions, as defined by any High pressure system, an approaching  to North Pole Low pressure system from the Pacific or the Atlantic is not repelled,  but rather joined by the pre-existing more Cyclonic air.  This fuels a further exchange of heat with what is left from the open Arctic Ocean,  slowing down sea ice accretion further,  with vaster thin ice areas having 24 hours a day heat warming surface air more than 100 Watts per square meter, will set up another accommodating invitation for further Cyclonic incursions.  perpetuating the true nature of Arctic temperature amplification during the long dark night.   WD December 24,2016

A much warmer Arctic:visual proof

   

December 19 2016 NOAA HRPT (darker),  December 18 1987 USSR Meteor IR.   Huge differences starting with surface temperatures,  a good +10 C warmer in 2016,  plus numerous features of wider open water.


 

GONE: #1 Famous ice bridge between Canada and Greenland,  a documented 

historical location used by Inuit dog teams likely for Centuries   Part of an ancient migrating route going back millennia #2  almost completely frozen Nares Srait.

#3 NE Ellesmere NW Greenland steady ice sheet,  virtually always surviving the summer.  

#4  The Big Lead,  a phenomena requiring very consolidated sea ice,  strongly frozen together mainly by very thick sea ice.  #5 Tidal leads.,  closely linked to tidal waves during greater tidal height variations.  They froze easily and disappeared quickly by drifting snow.  #6 Ice next to Spitsbergen, 

a mere small portion of the huge habitat dwelled by Polar Bears .  #7 Smith Sound Polynya  narrowing, a very important wildlife zone for Belugas, Narwhals, some sea birds and Bowhead whales.   Vaster ice span gradually push wildlife to a narrow area always open despite coldest weather possible.   Lately many whales get trapped by later refreeze of sea ice. 

NEW:   #1 Beaufort sea open very late in Darkness.  #2 very open Smith Sound,   #3 Thin sea ice leads radically not symmetric to tidal waves #4  Big lead not showing at all.  #5 narrow Straits much more open along with very thin ice very dangerous to walk on.  

A strict numerical sea ice extent interpretation may suggest  less change between the pictures presented separated by 30 years,  but there is much more than enunciated above,   the biggest one is clouds,  looking carefully at 1987, we see clouds barely surviving the very cold dryer environment.   These clouds lazily hung out with very little injection of moisture from the Northern oceans.    Winter was really set,  called "mid-winter" for a reason.   WD December 19, 2016