Sun line announces the return of persistent Arctic Anticyclone genesis

~ Spring 2013 had a remarquable period of persistent Cyclonic activity caused by adiabatic surface to air profiles.

~ 2014 already looks quite different

    Considerable effort drove me to determine the reason why Arctic 2013 was so much adiabatic in nature.  The very reason why Cyclones were extremely prevalent especially
from the spring onwards,  ultimately leading up to affect the sea ice minima,  by severely reducing sea ice compaction,  in effect stunting a sure to be greater melt than 2012.  Adiabatic air welcomes cyclonic invasions,  while stable much colder surface air acts as a barrier,  a wall against cyclonic penetrations.

    As you may read my spring based 2013 projection as seen on top of www.eh2r.com ,
the cyclonic activity to come was observed quite entrenched by affecting refraction effects.  Adiabatic surface to air interface dominated spring 2013 so strongly that I was certain and had no doubt that this feature will continue.  However,  early 2014 refraction optics show great evidence of the resumption of more normal Arctic Archipelago weather,  having a greater balance between adiabatic and stable upper air profiles.  In no
small part due to thicker sea ice between the channels caused by summer 2013 not having a great deal of sun ray heating of the sea by the everlasting presence of clouds
which permeated the entire 24 hour sun light season

     Triple Green flashes (seen red because of the filter) on top the much flattened setting sun of March 15 2014.    Clear signals by the heavily stratified nature of the lower atmosphere,  a sign that sun rays traversed an anticyclone.

    Same day right after not so famous but awesome sun line,  not seen like this so bright and strong for years.  

   The sun here is seen entirely compressed about 30 times.  Looking like"fire on the ice".
The sunset ended -2.23 degrees below the astronomical horizon.  Below -2 degrees sunsets were quite rare over the past 8 years.  The thicker sea ice of the Northwest passage cooled faster after a day of sunlight hitting it,  this created many isothermal layers right above,  since air didn't cool as rapidly,  ideal conditions existed for refraction ducting.  

     The basic difference between 2014 and 2013 is a presently colder Archipelago influenced by a a very frozen continent to the South,  in part created by strong albedo action from last summer overwhelming presence of clouds associated with persistent numerous cyclonic incursions.   This long streak of cyclonic activity is currently loosing steam because the local sea ice in a large area is healthier thickness wise,  at least around the archipelago, which is  a much colder area than the rest of the present day Arctic which has had a very warm winter.  The resultant after effect of newish anticyclone genesis should eventually  trigger the return of  more sun rays reaching the the most frozen side of the Arctic.  But since there is a temperature dipole in place, the rest of the Arctic Cyclones should continue enveloping the anticyclonic colder zone.  The very existence of stable air at the surface over the cold area will move about its source,  in effect creating more compaction,  and surely a lesser sea ice minima than last year.  WD March 15, 2014

Warming in the Arctic blasting cold waves Southwards?

~ Apparently the Arctic can do 2 things,  either it has a deeply frozen atmosphere  spreading outwards or be warmer at once.

600 mb temperatures closely represents the temperature of the entire troposphere.  Courtesy NOAA.  February 1982 (left)  Arctic Atmosphere was extremely cold almost covering the entire Arctic
while February 2014 (right) was substantially warmer,  with a much weakened Arctic Ocean winter.   Lame ,  more than twice smaller.  


How can most presenters claim Arctic blasts  lowering the temperatures enough in Eastern Mid North America to almost freeze the Great Lakes completely,  when a really cold historical Arctic had less an effect on the same lakes?   The answer is spatial compression and also a greater potential of heat radiation to space over the continents primarily because the continents cooled more readily as they are physically unchanged, opposed to a cloudy Arctic bombarded with Cyclonic intrusions having changed Sea ice wise.   

The latest North American "Arctic blast"  was influenced by a very small Archipelago cold air vortex,  the Cold Temperature North Pole (in blue),   which grew significantly in size and cooled further over Sub Arctic!  It was  not quite an Arctic blast.  NOAA's satellite 
missed some extent of the boreal forest area cooling in Mid-Quebec,  radiosonde measurements there were in excess of -43 C at 600 mb.  But the rest of the Arctic ocean 600 mb temperatures were more than 20 C warmer.  

The also common saying "the Arctic Cold air" was replaced by advection from the South, "pushed away" by advection.   Not quite so.   Over the Archipelago,  where the coldest air was during Feb 23-26,  the air warmed from a trough of warm air extending itself from a Baffin Bay Low pressure along with and incursion of warmer air from the North!  Originating from the North Atlantic no less. The Archipelago atmosphere primarily warmed literally from above both ways,  from Latitude and altitude.   The correct interpretation of the latest "blast":  the remnant of coldest winter formed greater over the Boreal zone,  it was a Boreal blast!  WD March 6, 2014    

The Polar Jet streams further North

   Let us take 2 known climate records from history,  the very cold winter of 1981-82,  cold either in Europe or North America,  and the very strange winter of 2013-14, cold in some places and warm in some others.  On NOAA climate composite chart on top we can see jet stream largely Southwards compared to January 2014 being largely more jagged  and more to the North.


         Reason for 2014 extreme North Pacific location may have something to  do with North Pacific temperature anomaly and extremely much warmer Arctic Ocean air temperatures.  On a whole the Polar Jet Stream must and did move Northwards as it is overall warmer in 2014 compared to January 1982.  This 2014 pattern gave the strange weather like California drought,  weird cold winter storms in SE US,  massive storms from one strong Cyclone after another hitting and flooding the British Isles and Ireland,   a warmer Olympics even if it is in Sochi.  Finally a much warmer Arctic warmed by the same Cyclones hitting the Isles, and also from Cyclones coming from the North Pacific.  Warmer over all weather means the Jet streams moved North and meandered more steeply, causing unusual patterns creating havoc instead of more predictable weather.  WD February 17 2014...

Great sea ice melt mechanics

~2013 minima results needs be explained
~2014 melt gearing up to be big

Continuous warm anomalies over the Arctic Ocean have been as incredible as the lack of sea ice compaction last summer.  Both result from the same polar vortex wave arrangements, almost  unrelenting like UK storms which flood the Isles and head towards the Pole.  So I am truly not surprised about current low sea ice extent, it was suggested at the time of last minima by the very same cloudy cyclonic coverage which made the minima bigger.  Again the big question is whether sea ice compaction will return come this summer,  if it does,  I can easily foresee a greater melt than 2012.  That is the big if.  Something must ward off these cyclones from hitting the High North so often, particularly the pack ice center.  This something may be El-Nino or more likely a low sea ice extent area of relatively thick ice in the spring. Once the Polar shores are free of ice, a confluence of regularly positioned cyclones may return the Basin Gyre clockwise.  One over Barents and North Pole, the  regular expansive Baffin Bay Cyclone and lastly  over East Siberian Sea.  These 3 will generate an anticyclone covering the remaining Pack ice.  

        Arctic Ocean  shorelines with open water create anchors or stabilizes Cyclones to remain on top of water.   A near persistent Low centering the Arctic Basin, same as last summer, may bring a cold spring .  Ice clogged shoreline areas favor Highs instead of Low pressure cyclones fueled by water.   An earlier than expected shoreline "spring break" of the entire Arctic Ocean sea ice area may change polar patterns though.  Weather patterns rarely remain the same forever,  when they appear to do so,  they set up the new weather system arrangements to come.  

  Search for "Spring Break"  2013;   

      "Spring break" is seen when the entire Arctic Ocean pack gyrates almost uniformly, when it appears to be free from its connection to land,  the best way to see it is with satellite picture animations,  single high resolution satellite pictures do not reveal this event well:

   2007 sea ice looked better than 2013 on the same May date.  But the end result  at minima was different.  

     Although by May 14 2007,  the entire sea ice broke free from shores and rotated clockwise for the first time:

      Using available animation, when the big lead off the Canadian Archipelago coast spanned all the way to the Atlantic,  the entire ice pack was seen rotating on May 14 2007.   It was the beginning of one massive melt of even very thick ice.  

    2013 had a different look, plagued by steady Low pressure cyclones over the Arctic Basin, which killed the usual compaction favoring clockwise movement of sea ice.   By August 2013 the melt was strong but stayed in place, favoring 

a wider over all extent of loose pack ice.     But by mid May 2013 there was no apparent "Spring Break"  until August with available video   from NASA.

   The entire Arctic Ocean ice didn't appear to turn clockwise at all,  it was an anti-compaction melt season.

      There were those who believed 2013 was a "recovery"  from previous torrid melts.  But these suggestions were ignorant about the holistic nature of sea ice.  It was not a recovery at all, but another great melt which didn't move normally. A continuous repeat of the same weather pattern causing this unusual lack of movement is highly unlikely.  But even if it does,  the sea ice will melt just as much but apparently more slowly year by year.  But I'd expect the return of the Arctic basin Gyre because the clouds have created a lower extent of thicker ice, this will allow an earlier spring break. WD Feb14,2014

Circulation GAME CHANGER: El-Nino looms

~Certainty is growing in upcoming El-Nino
~Cloud seeds in the high Arctic starting to show  at 4 degrees above the horizon


     Dr  Masters caught this NOAA statement:

”An increasing number of models suggest the possible onset of El Niño. Strong surface westerly winds in the western Pacific and the slight eastward shift of above-average temperatures in the subsurface western Pacific potentially portend warming in the coming months.”

NOAA may  be referring in part to this:

                These graphs  done by the Earth & Space Research  Institute acknowledge a sea current output (in blue) which usually precedes the sea surface temperature trend.   As the top graph demonstrates,  ENSO sst's 
will rise soon.   


        In the high Arctic,  I have recently observed higher than troposphere dark cloud streaks above the horizon,  they showed 4 degrees above the horizon on most days, and closely reflect the same equatorial Pacific sst trend,  what needs be observed is higher than 4 degrees horizon clouds:  

    March 2010  El-Nino was already fading ,  High Arctic persistent stratospheric streaks reached 10 degrees above the horizon.  

  zoomed  October 2010 stratospheric black cloud streaks mixed with some bright ones,  these coincided with the end of El-Nino of 2010,  these streaks were as high as 5 degrees above the horizon.   Presently 4 degrees was seen many times.  


              Confidence is High ,  El-Nino is likely returning this year,  the Global Circulation will change accordingly,  this will affect sea ice melt of 2014 in 2 ways; 1 there will be more clouds,  and 2 the persistent Arctic cyclonic presence of summer of 2013,  the pattern making it so may be changed.    WD Feb7, 2014

TWIN CTNP's winter's much smaller coldest grip

~Weakens winter were it should be strongest

~Creates smaller atmospheric mesoscale regions susceptible to migrate along the real polar vortex waves.  

Again not an Arctic blast affected some parts down South,  because the temperature anomaly chart makes the Arctic +5 to +20 C above normal:

Courtesy NOAA

   While in Atlanta 2" of snow turned to ice paralyzed the great Southern city,
historically not a frequent event. There seems to be a disconnect between a warmer Arctic and regionally small extreme cold weather.  The concept most TV weather spoke persons never talk about is the concept of isolated coldest atmospheres affecting regions not accustomed.  There are 2 at present,  one in Siberia, the other over North Eastern North America, both have weaker winds at 250 mb Center.

Courtesy NOOA

    The jet stream usually sits next to where the coldest atmosphere exists, if the size of the coldest air extent diminishes the jet bends more and is less expanded towards the equator.    CTNP's in black rotate counterclockwise.

       
       The bigger Cold temperature North Pole cell is over Siberia, which injects cold air west of the Urals.    The  North American Cell is way smaller and will not last.
It gradually diminished over quite some time,  being well South of its usual location demolished its strength and area, unfortunately to the detriment of people not use to snow.  The North Pole,  still in darkness  is quite warm despite the presence of a high pressure immediately next to it.  The dual CTNP nature will evolve further, likely being prominent in Russia, not so over North America.  Along with this change comes the different weather and essentially warmer temperatures.  WDJan30, 2014

Count the calories, Arctic sea ice needs a heat diet.

Looking back,  at December 1981 when the Arctic Ocean sea ice was much thicker,  we can see the outline of this vastly thicker sea ice with Outgoing Long wave Radiation (left):

     NOAA recalculation to the right shows the outline of older multiyear ice for December 2013.   Here is proof in the effects of sea ice thickness on climate.  In December1981 there was far less radiation escaping to space compared to 2013.  Roughly 20 watts/m2.  

     This necessarily means thinner ice has an impact in profound ways,  the buildup of winter,  how big it becomes,  how long it lasts,  depends on how cold the Arctic and Sub-Arctic surface areas become.   A prolonged cold period permeating a huge area of the Earth defines the winter bitter, too long,  miserable.   From the onset of a greater sea ice melt at minima, the world wide dark season becomes automatically warmer, shorter, less expansive,  even with ideal conditions of thermal radiation cooling to space,  the thinner than multi-year new ice warms the atmosphere,  not only by thermal radiation from the sea,  but because of its fragile state,  creating more leads,  venting moisture and gases to the atmosphere throughout the winter, as opposed to a period called spring "break up", when vast amounts of organic and inorganic gases, naturally trapped under the ocean for many months,  gets unleashed with great amounts of water vapour,  at about Mid-April onwards,  when lower clouds and ice crystals overtook the sky.   This eruption from the sea protected sea ice further by reflecting resurgent sun rays to space.  For about a decade, this happened a lot less,  while during these last 10 years or so the process of all winter venting did the opposite,  it clouds the Arctic further during the dark season,  deflecting radiation usually heading to space back to the sea ice.  The OLR chart is worse than it seems,  a lot more  of thermal radiation returns to surface. Thus from darkness a warmer Arctic is seen on historic charts.


  Translation in temperature terms

The larger dark blue average temperature  covering the Arctic Ocean was about 242.5 K, or -31 C.
That is the average temperature of sea ice surface for December 1981.

 We have seen that thick ice has its own thermal imprint seen all the way to space,  it emits a lesser heat signature keeping the underlying sea cooler all year round.  A key feature of Polar biology is how not diverse it is, how encroachment from southern species reveal this fact.  At the core of this unique desert like feature is a steady predictable colder than not air temperature,  rarely having great variances aside from the impacts of large cyclone incursions.   A great change in temperature affects everything and everyone:
 

The larger light blue for December 2013 is a mean temperature at about 247.5 K a full 5 degrees Centigrade above 1981.
The main obvious question to ask is how this temperature increase affect  the entire Arctic?     The immediate weather related answer is that there are lesser or weaker thermal inversions at the surface to air interface.  These inversions are complex,  but heat essentially renders them more scarce,  this has huge implications with Anticyclone Genesis.  What makes a High Pressure is descending air spreading outwards to a Cyclone.  During the Long sunless Polar regions this air circulation favors a cooling process,   air skims the risen to surface permafrost and it cools on its way to the Cyclones.   Very cold air has much more stable properties than warmer,  the cooler air has long shed its moisture , giving a negative feedback,  the air freezes further by radiation escaping to space  decreasing temperatures further. Multiple thermal layer layers are created one on top of each other,  the coldest in bottom warming above.
Like the "Jupiter refraction bands"  seen breaking up the sun disk at sunset:

     March 31 2004,  very cold ground triggered isothermal boundary layers are seen  breaking up the sun disk even to bend along with them diagonally.  The sunset on
top of the hill captured a magnificent green flash,  along with bent layering features.

     Although distortions caused by by boundary layers still persist,  as this March 24 2012 demonstrates.  However, sunsets are gradually moving Southwards,  the sun is seen more rounder southern like earlier in the year,   the effect of thinner ice is also seen by the shifting horizon as well.  This awaits another presentation.











Warming off the ground changes the sunset,  the sun looks rounder, the layering vanishes.   Land and seas capable once of fostering great anticyclones transform to cyclone bearing zones.  April 28, 2013.

     Isothermal layering on a grand scale fosters High pressure systems.  During Polar winters these systems cool the Earth a great deal.  If the Cyclogenesis system balance continues to change,  like during current reduction of disappearance of sea ice as of current days,  winter has no other way but to shrink in size, and be more wild and variable temperature wise because what is left of the cold air zone moves around with the rotation of the Earth.  WD January 11, 2013

Current North American "Polar Vortex" media definition not quite accurate

Wikipedia definition:

"A polar vortex (also known as mignogno cyclones, polar vortices, Arctic cyclones, sub-polar cyclones, and the circumpolar whirl) is a persistent, large-scale cyclone located near one or both of a planet's geographical poles. "   

      Well  the North Pole is not in Minnesota USA.   Unless there was a huge geographical shift.  

   More correct is the following definition still from Wikipedia:  

"The Arctic vortex has two centres, one near Baffin Island and the other over northeast Siberia.^[2] In the southern hemisphere, it tends to be located near the edge of the Ross ice shelf near 160 west longitude.^[3]When the polar vortex is strong, the Westerlies increase in strength"

     So the current US weather is not a polar vortex,  but something rather more exotic,  more a propos to a lesser worldwide winter days when the jet stream gyrates weirder than usual,  it has more to do with the snow laden ground night sky being clear and the day time with fewer sun hours,  it is the Cold Temperature North Pole   (CTNP) .

    Definition of CTNP:   Center of the coldest place on Earth.  It is usually one area emerging from a synergistic effect which is the culmination of the lost of heat to space,  it is not North or South Pole Centric.  But may have secondary,  isolated spots.  The circulation around a CTNP is counterclockwise.
By definition a Cyclone at center often without clouds.    Its location is calculated by the equivalent temperature of the entire temperature of the troposphere, or the Density Weighted Temperature.     In lack of actual DWT charts we must contend with 600 mb charts which often mathematically represent the temperature of the entire atmosphere,  since 600 mb charts are not often published,  either 500 or 700 mb charts may be used.   In this example

a US 700 mb map,  the center of the  2nd coldest measured atmosphere in the world is over Illinois!   @ -33.6 C #2 CTNP.    Ust-Barguzin Siberia has the coldest  # 1 CTNP cell at -34.9 C.   

        While the Wikipedia  cited Baffin Island "vortex "  is CTNP3   #3 coldest.        CTNP's further to the South do not last long,   disappear rather quickly.   While Arctic CTNP's last longest,  sometimes months.       But the reason why central North America is cold today was because a few days ago there was another CTNP over Southern Quebec,  which drew colder air southwards to its West.  Warmer air and cyclones were drawn in to its North .    The Southern Quebec CTNP warmed substantially and is well over Newfoundland on 6 January 2014.   WD 6 Jan 2014.   

CLOUDS major play; explains a cool 2013 Arctic summer and warm Arctic fall.

~ENSO split NORTH SOUTH  bipolar personality, south Atlantic hurricane killer

~Global Warming may not be explained in simple terms, one must study to reveal never ending natural variations,  where they may be and why they exist.

     As written below,   the cool Canadian Arctic summer was a complex contribution by 2 major atmospheric players, anti beaufort gyre contrarian winds caused by near persistent presence of cyclones over the Arctic Ocean,  and extensive cloud coverage,  of which were even present over rather large Arctic High Pressure systems which did happen more often lately.

  The great Arctic cloud coverage of 2013 must come from extraordinary reasons,  the -extra-   is of course ENSO but there was an 'ordinary';  the North Atlantic and Pacific, look carefully at the last 4 months,  El-Nino loomed like North of the equator,  La-Nina was just South:

Virtually the same SST image every day for 4 months.  Thanks NOAA...


  One reason why there were fewer or no hurricanes in the South Atlantic,  but lots of thyphoons in the Pacific was and is that the Northern Hemisphere is in El-Nino mode.  While the Southern Pacific is very much like a La-Nina.  ENSO has a split personality syndrome.  Furthermore the North Pacific is unusually warm.  The cloud seeds are planting continuously,  therefore clouds under a high pressure regions are possible.


Conversely a cool Arctic summer,  can't contribute to a cool following fall, not logical isn't it?  However, the clouds persist.  Giving naturally a much warmer fall:

   DMI nice North of 80  Graph says it all.  The clouds are keeping the Arctic fall warmer.  wd October 6,2013

SEA ICE phase changes mimicked by the vertically shifting horizon

~Seeing the thermal effects helps explain the sea ice melt
~ A series of May 2013 days remove the veil from thermal variance mysteries


    In order to establish a 12 melt hour period and prove it, one must record data.  Last few days of photo chemical ice crystals showers slowed the melting period,  for now it lasts about 10 hours a day.  The image sequence below shows a relatively complex drop of the morning horizon as the sun elevation rises.  One may observe the 3 underside phases, freezing (extreme left)  until  steady state 4th from left,  and melting (extreme right).    Underside melting will go on until long wave outgoing radiation become weaker and the ice horizon will rise again in about 10 hours.

    {take sequence to desktop and zoom}   All pictures from land to sea with fixed mount camera.  

Mean time from extreme right melting picture the horizon will drop further and further.

  The total thermal effect from top of sea water column twinned with more intense sun rays on top of ice obliterate atmospheric boundary layers (inversions) created during the night right above the ice.   This shifts the horizon to go lower. During the night, in this case from the much lower midnight sun,  the underside freezes because the net thermal balance favors it, this causes the horizon to rise greatly.    When the sun rises further in elevation ,  sun rays penetrate a thinner and thinner atmosphere, the rays have been less depleted and hit the ice.   The albedo effect theoretically should deflect most of this energy upwards.   But sea ice,  even covered with snow seems to absorb a significant amount of rays, sufficient to change its net thermal balance within 1 hour as seen here,  making it emit more long wave radiation along with short wave deflections (which does not warm air  as much).   We literally see here sea ice thermal emissivity change to the point when the ice 

can't possibly be freezing or accreting.   The underside of the ice is most bombarded with long wave radiation from above and below, thus it melts.

First 12 hour underside melt observed

History in the making:

Same May 10 2013  day, 11 hours later (extreme right picture)  underside ice was still melting.  The day got cloudier a few hours after the beginning of the underside melting.
The clouds were mostly broken stratocumulus at 3000 feet ,  which reduced the impact from photochemical ice crystals (less sun,  less photochemistry).    This reduced sun ray obstructions to surface.   Here seems to be another discovery,  total clear air makes the sea ice more thermally active,  clouds mixed with sunlight reduced wild thermal fluctuations especially in the evening.
This kind of weather is possibly an ideal cold weather sea ice melt accelerator.   At any rate,  after 11 hours of underside melting, the weather was such that I lost the clear horizon, distant snow showers reduced visibility.  However secondary observation spot showed a continuance of the lower horizon.   So for the first time in history, 12 hours of underside melting was observed and nearly completely filmed.   This means that the sea ice at 75 N 95 W is thinning, cracking and vanishing.  Slowly for now, but much faster in no time.  2012 during same May period had consistently smaller melt periods.  The underside ice column also has a significant layer of bottom "soft ice" confirming the visual observations.

wd May10, 2013


Overnight clear sky cooling slows the melt

Clear weather is a double edge sword when it comes to thawing underside sea ice,  this morning (May 12) I measured a later start of melting phase by 46 minutes than from May 10 (above).
Below is a darkened on purpose 1 hour phase change sequence:

The net effect of clear night air was to cool sea ice a great deal more especially with the low midnight sun.  This caused a later freezing to melting phase change,  remains to be seen whether a clear day can counter balance this shift and make the melting period last just as long than previous days.  Clouds with sunshine seem to be the most potent thawing combination.

8 and a half hours later,   apparent underside thawing stopped ,  3.5 hours earlier than previous days,  in cool very clear air.  This is very interesting.  The likely reason is the latent cooling from the clear  night prior,  freezing the soft ice column further than usual.  There was cooler ice to start from, ultimately it was not warmed to previous days balance.  If left to clear air only, the freezing process would last longer in the spring because of the low midnight sun.  Pictures will be placed  up tomorrow.

Clear Sky conundrum, the ice freezes more
~With confirmation of melting phase.


The next few clear days from May 12 were strange and exhilarating.  Turns out that clear skies were indeed not conducive for melting sea ice,  even with the midnight sun
at reasonable elevations.  From May 10 and 11 melting periods of 12 hours or more, day 12 went to 8.5, 13 8 and day 14 even less long.  Despite 24 hours sunshine
and on day 14 warmer temperatures.

First on day 13, I have confirmed a melting phase.  If sea ice is one solid block of uniform ice and for example there is no melting going on when there is more sun rays hitting it, the horizon should drop continuously,  without interruption similar to what it does at night,  raises continuously in direct relation with the lowering elevation of the sun.   Inversions are such that there is no limit to the horizon rise,  if there is less and less rays the surface to air interface inversion becomes stronger and stronger.  Causing a form of looming,  the sea ice well frozen looses most of its energy to space,  since the ice is at same thickness the only variable is the long wave radiation escaping to space.  Theoretically with the one block of ice getting warmer as the sun rises, at local apparent noon,  when the sun is at daily zenith,   the horizon should be lowest,  it was not observed as doing so.   The horizon reaches a steady point and stays there,  similar to boiling water, when the temperature reaches 100 C it stays there until all water evaporates.  Likewise with sea ice,  the underside melts,   a new thermal balance is reached where the horizon stays at constant elevation.  What likely happens was triggered by the changing nature of the sea ice column when water melts on its underside the ice column is not the same.   Its a mix where sea water is part of the process, at that moment there is  a much larger body of  matter to exchange heat with.   Unlike 1.7 meters sea ice, this sea water may be considered as having infinite thermal capacity,  therefore there is a lull in the lowering of the horizon.  Its the same as air interfacing with open water ,  a thermal exchange causes a fixed horizon level, only to be changed when especially the air temperature just above varies.  A similar effect occurs when the sea temperature becomes different.  But as seen below,  especially places like Redondo beach California,  a small difference between sea and surface air temperature doesn't shift the horizon a whole lot.     Sea ice is unlike the sea surface because it is insulated and may be considered a body separate from the sea until it starts melting in the underside.


Bottoming out of dropping horizon:

The first picture from left until 4th spans nearly 3 hours at about the same horizon height, 
despite the pre and post local apparent noon sun.   Very similar to sea to air horizon when the sun can't heat the sea significantly enough to make a shift.  The furtherest picture right was equally fascinating, this phase change occurred significantly earlier than previous days, 1 hour earlier,  despite clear blue sky compared to cloudy weather.

   Although this sequence just above (repeated twice more),  represents a better understanding of what is going on under the ice surface,  the last one furtherest right was puzzling.  Why would there be more freezing on a sunny clear day?  The next 3 days were clear,  it seems the ice was made warmer by clouds,  then sea ice cooled dramatically at first clear night,   slower on the next following days.
The freezing period was progressively longer,  with subsequent clear nights and days of May 13 and 14.  Even though the temperatures were 5 degrees warmer on the 14th.
From 12 hours of melting in clouds,  the freezing became stronger  in each subsequent clear air day because there was an adiabatic process which evolved from weaker to stronger,  since the air above was relatively still cold,  the adiabatic process on the 14th was equally more unstable.  In the fall,  particularly over wide open Arctic water,  adiabatic air profiles favors surface cooling.   Only the higher 24 hour sun can compensate for the heat loss from adiabatic process,  likely as records show end of May at 75 N.  When clear air will likely give melting longer than 12 hours.   The other discovery here is equally important,  partially cloudy weather has been the greatest factor increasing melt times, so far....WD May 15, 2013


Returning clouds stops sea ice night cooling

Subsequent clear nights of May 12,13 and 14 amazingly slowed the melting process until the 14th when there appears to be a gain in late melt time from Local Apparent Noon.
May 15 late AM. at first it was cirrus,   approaching from the southwest,
then lower clouds from a small cyclonic system.  The results were interesting,
the high clouds gave similar horizons than with clear skies, at first,  then the horizon never bottomed out for long afterwards (line in yellow).  In the evening,  the usual sudden rise of horizon from long wave radiation loss to space slowed a great deal compared to preceding day, so this means a lesser extent of cooling. Resuming the longer  melting period especially for tomorrow, since the night is cloudy.  I'd expect an extensive melt period nearing 12 hours if there is partial skies again.   We shall see...WDMay 15, 2013

Low clouds exceed 12 hours melting again.

Night of 15-16 was cloudy ,  day 16 equally so.  Fortunately late evening gave ideal conditions to study,  mostly cloudy but with a clear  horizon.  Instead of the usual rebound with clear or high cirrus,  the horizon  remained low indicating a likely 12 hour melt day.    Again broken clouds peppered with sun breaks gave the maximum thawing effect.  This great method of observing the Thermal balance of sea ice shows an elegance in heat exchanges.   A continuity,  a follow up from the consequence of the previous day and night.  Clear days cool the ice more than warm it,  until the midnight sun becomes higher in the sky.  Cloudy days prop up the thermal influence from sea heat, bouncing back from cloud bottoms instead of escaping to space.  The clouds reflect back the heat from the sea ,  which as the graphs above show,  does not bottom the horizon elevation as much as the sun during a clear blue day.  But overcast conditions are lethal for sea ice growth,  something
most specialists always knew,  but not for the fact that clear skies- not at the North Pole -  give a strong diurnal thermal variation favoring ice accretion. WD May 16,2013


What happens when the sky is mixed 50% blue?  

Same graph as previous day except for purple line representing May 17.A mixed sky shifted the horizon all over the place.  There was at first mainly cirrus which gave practically the same horizon heights as clear skies, bottoming slightly higher than a clear blue day.  Than at evening the clouds, even cirrus moved away,  causing an abrupt change of phase from melting to freezing.  Afterwards the sky dome changed appearance
with a mix of low clouds and cirrus taking turns over the filmed horizon light rays path.
When low clouds dominated the horizon dropped, when cirrus covered the ray path
the horizon rose.   wd May 17, 2013


Horizon BOTTOM elevation confirms a deep water column source of energy

May 18,  measured the horizon at Local Apparent Noon ,  2.43' above a fixed point again, as often as the sun is 30 degrees high and there is no clouds  or just high Cirrus.
It is a wonderful repeated observation confirming the under sea ice is melting.  Sea water temperature can be considered a constant,  only the sea ice and surface air changes in nature.   So today,  a warm sunny day of spring,  has warmer temperatures than preceding days,  by more than 10 degrees C.  Yet the bottom LAN horizon is a constant?
Something is making it so:

The horizon can drop further than 2.43',  this is a 1.73' arc minute September 2010 open water example. It can lower even more.

Consider again the sea ice one single ice sheet,  uniform in density,  1.8 meters thick,
from direct sun rays it's horizon should lower and lower along with the rising towards noon high zenith sun.  In the High Arctic it does so daily.  But then the horizon stops lowering,  remains at near constant elevation only to rise when the sun is about 25 degrees on its diurnal course towards the midnight lower in the sky sun.    If perfectly insulated from sea water, the top of the sea ice should reach a thermal balance similar to the picture ( just above, with 1.73' above fixed point),  but it doesn't.  Something is moderating the course of events.  And that is the sea water thermal signal mixed with the ice thickness which now doesn't appear to change,  for that to happen something must give,  this something has to be melting sea ice.  The energy gained by sun rays twin with heat energy from the sea, merge to melt underside ice keeping the horizon constant.  Water replaces bottom ice, this should make the horizon lower but it doesn't,  because sea water does not change in temperature (just like the ice next to it),  there is a vertical displacement of water just melted.  Being replaced by  constant temperature water from the much thicker water column.  When the sun energy is insufficient to compensate for thermal radiation escaping to space, the ice bottom refreezes,  insulating the ice further, lengthening the insulation from top of sea column to top of sea ice.  This changes the structure of the surface to air interface  immediately above the ice.  wd May 18,2013


New horizon bottom,  the ice melted until the skies cleared

May 14                                        May 20                                May 22
A long series of cloudy days eventually reduced the horizon elevation to about 2.13' above a fixed marker point.  On  May 22 with clear afternoon sunshine,  the low horizon was repeated.  This means that the ice thinned, or the column of soft bottom ice has gotten even thicker.     May 14 had 2.86' horizon, May 20 2.13' and May 22,  after cloud effect,  the horizon , even with high sun all day,  the same horizon was 4.32' all at about the same some position in the sky.  


    On May 22 the same low horizon with a strong sun above 30 degrees elevation,
resumed the horizon with low clouds achieved the day prior.  This new refraction bottom  is likely due to a new state of the the nature of the sea ice,  either thinner or physically altered by  a different softer to hard ice ratio.   Warmer temperatures did not play a major role in this change.    It is the net balance of thermal rays,  namely Long Wave Radiation which created these interesting changes.  WD May 22 , 2013


MIDNIGHT SURGE

May25 3 PM left, later past midnight right,  even with much milder temperatures the solar diurnal effect still takes place, especially with clear skies.  The sun at 6.4 degrees 
at midnight is by far weaker and not capable of melting underside ice.  At this late time there is freezing even at -7 C with about 2 meter sea ice.  Long wave radiation escapes to space, particularly from the top of the sea water column, cooling occurs bottom side gets coldest as opposed to earlier warmest.  There is a couple of interesting effects,  namely 
a 6 degree sun in  February noon gave a much lower horizon.    There is resonance with the sun ray intensities,  if the rays lessen in total photons the horizon rises,  the opposite is true even during much colder weather.    A sun 6 degrees from the South at noon usually has a lower horizon than with a 6 degree midnight sun.  There seems to be a photon momentum effect., but its likely because the ice cools further from a warmer point than from a much colder state of total weighted temperature.   

WD May 26,2013


For a better understanding please read below:

Data gathered from Optical Refraction above sea ice. An introduction