Almost everything predicted for 2017 is turning out

http://eh2r.blogspot.ca/2017/05/annual-bit-late-2017-northern.html

  The linked above annual spring projection of important weather events is doing just fine.

" The Okanagan valley BC will be hot and dry at first then turn quite wet, Midwest North America will be mostly dry and very hot"

  My favorite prediction written when the Okanagan was on the verge of major flooding due to extensive winter snowfall and spring rain.  The "theory of persistence"  would have made this catastrophe possible,  but the Northern in provenance atmospheric circulation saved the valley (as projected).  The moist Spring turned to above Normal temperatures:
 https://www.esrl.noaa.gov/psd/map/images/rnl/sfctmpmer_30a.rnl.html

Western European Heat wave,   check : http://www.france24.com/en/20170622-paris-pollution-peak-driving-ban-europe-heat-wave-longon-portugal

Less American Tornadoes,
check :http://www.spc.noaa.gov/climo/online/monthly/newm.html

    Note the earlier more intense period of tornadoes,  preceding lesser numbers when there should be more.  The prediction was about this period after mid April.

ENSO to Neutral, 

 check: http://www.ospo.noaa.gov/data/sst/anomaly/2017/anomnight.6.22.2017.gif

   Note the residual cloud seeding from El-Nino 2015-16 replenished water to many areas of the Earth stricken by drought.  

"I would expect record number of melt Ponds -late- from all that thick snow cover. This will accelerate the melt rapidly, numerous melt ponds will signal the start of very rapid melting, after seemingly sluggish melt daily rates interspersed with at times great variations caused by the lack of sea ice consolidation."

   This is indeed happening.


"when this snow disappears in June, there will be huge water ponds, the ice will vanish extremely quickly then after."

   Needless to say,  let us use Barrow Strait Canada with picture animations:

  In 2016 Barrow Strait had significant snow cover over sea ice,  the Strait cleared of ice late June:

http://eh2r.blogspot.ca/2016/07/sea-ice-affected-by-lot-of-snow-end.html

   Winter 2017 had significantly more snowfall especially at end of the long night:

  Down the Baffin Bay drain!   One month earlier than last year.  The sea ice did not stand a chance to withstand even seasonal weather,  because it was so thinned by a very thick snow cover during long Arctic night accretion.  The same is expected to happen wherever there was more snow cover over sea ice,  which may be pretty much the entire pack.  

       So now we wait Barrow sea ice disintegration to hit the larger remaining ice pack.   WD June 24 2017

Fram Strait channel doubles, North Nares Strait has no Greenland stable sea ice shelf at all

We notice the usual late May early June "spring break" especially North of Ellesmere Island, the Big Lead reappeared along with many Northwestwards lateral fractures. The entire pack turning clockwise is a common feature at this period of year.  What is very unusual is is North of Greenland total collapse and disintegration of its perineal stable sea ice shelf,  which in the past reduced the flow of  ice through Nares Strait substantially.  In history,  the marking feature North of Nares was a circular opening of water surrounded by stable ice:

  A few years ago, 2 weeks later,  as seen through clouds,  North of Nares circular current and broken ice zone,  was mainly caused by stable ice,  now gone.  It can only mean more substantial sea ice lost, the steady ice shelf barrage is gone.   WD May 30,2017

North of Nares Strait region sea ice, once steady stable perineal, now thin unstable seasonal

   May 21 NASA EOSDIS captures for 2017, 2013 and 2015,  May 21 selection was chosen as the earliest date comparable,   extensive cloud cover forced the choosing of  later dates were picked for 3 other pictures:  2016 June 12;  2014 May 27 and June 15 for 2012.  Despite the much later dates sea ice was never for the worse compared to May 21 2017,  broken and smashed up,  is true to present days weakest formation of very thin tenuous sea ice.  As the NASA clips suggests, it was very recently not always this fragile North of Nares Strait,  despite a near permanent Gyre and tidal current,  2012 ice looked substantially thicker and stronger a month later.   This year to year animation gives the impression of a progressively continuous sea ice deterioration.   In the late 80's this ice sheet especially next to Greenland  was rock steady year round with only the current breaking it up at Northern entrance of Nares.  The broken up appearance of sea ice in 2017 demonstrates the total collapse of the steady but important thin sea ice shelves (3 to 5 meters).  WD May 21,2017

Spring Break from within the sea ice core, 2017Arctic Ocean sea ice is already unusual, fluid movement captures

We look here at May 17 to 20 2017,  20 with the missing gap,  a huge opening lead (amongst many other large ones) spanning a great deal of the distance  from Russia to Canada, something like 2 to 4 kilometers large, getting bigger daily,  moving 10 kilometers in 3 days,  you can't miss it,  it is the biggest black line,  clearly open as we see it through the clouds.  

Spring break usually occurs on the coastal areas,  when rotation of the much consolidated pack  usually turns with the Arctic Ocean Gyre current,  clockwise.    If the pack is not so one piece of frozen mass,  then the break should occur everywhere else as it does indeed.   

  May 27 2016 had a small semblance of May 20 2017 look.  2017 sea ice was more fluid all winter largely as a result of the under emphasized big Minima Break up of the densest Canadian Pack ice seen here.  The lack of the usual super dense pack twinned with warmest winter in Arctic history, gave a new sea ice field, by all dimensions, temporal and size.  WD May 20,2017

Annual a bit late 2017 Northern Hemisphere summer-fall-winter projections forecasts, by unique data acquisition means.

~ A surprise cooling temperature shift caused by too much snow on the ground,  changed winter from all time cloudiest and warmest,  to seasonal.
~ It doesn't spare nor slow sea ice ultimate demise
~ 2015-16 world all time warming trend may be slightly stalled at a very warm level

Prognosis:

If a graph would suggest definite linear world wide cooling since 1976,  it would be this one:

2015-16 

However sunspots don't seem to greatly impact the Total Solar Irradiance (TSI) currently at 1361 w/m2. 

Let us look at this Colorado University  TSI graph and correlate with the big disk itself:

TIM graph just above,  on April 1 2017,   suggested if we consider "little ice age theory" analogy a drop in the number sun spots,  a commonly thought direct relation for sun output,  which would mean lesser sun spots.  Above is what 1360 w/m2 looks like.

End of April a tad brighter sun,  with less a few less spots had greater energy output by a ruckus 1 W/m2.  Sunspots not quite heat related  despite being literally colder areas on the sun.  

     But the sun position may be very useful in determining the state of the atmosphere,  which is very very thick from telescope to space at the horizon,  sunlight can penetrate thousands of kilometers of air,  a huge amplification of the nature of the atmosphere can be observed just above the ground thanks to the sun:

April 14 2017 Katimavik sunset, named for a long ago, now 50th anniversary expo 67 Canadian pavilion.  This sun set 3 degrees further Southwards, indicating a lack of a strong stable inversion temperature gradient.  The interpretation of this may go 2 ways,   either there is less warming above,  or more warming at air next to sea ice,  the former was the case.  The atmosphere thickness here is in excess of 2000 Kilometers.  

    This year, sunsets were commonly strongly Southwards in March,  more Northwards in April,  this reflected a sudden cooling of the entire Canadian Arctic which gained prominence as it spun a small vortex shutting down the East coast of North America.   This cooling came from Central Ellesmere,  partner in cooling crime with Greenland,  dry air from the 2nd biggest glacier in the world,  along with Ellesmere covered with thick snow which fell from moisture rich warmest Arctic winter in recorded history ,  changed this amazing cloudy warm winter to a normal end.   The clouds were more scarce from about the time of greater cooling ,  coinciding with  March early April usually not so cloudy period,  allowing for many sun disk pictures,  not as numerous as last year,  but within the most numerous seasons,  near 3rd place after 2016 and 2008.  

Sun disk data amazed,  the March April Canadian Arctic archipelago atmosphere was seasonally cold

What is the score ?   While reviewing all time average vertical sun disk expansions with respect to 120 decimal altitudes captured between 2002 -2017, from -1 to 10 degrees elevation.  According to refraction laws, vertical sun disk dimensions should expand with ever increasing in impact from Anthropogenic Global Warming,  it is a good way to check on the Global Temperature method, differently, optically.  The predictive record of previous sun disk comparisons was very good, with uncanny precision in determining Northern  Hemisphere yearly average temperature in April,  8 months earlier.    So without hesitation here are the 2017 results:

   2017 has 490 observations to date,  a year by year average of 6.25% for all decimal levels with maximum expanded sun disks should be considered normal statistical average.    #1 expanded is 2016,  with 15.8%,  #2 2015, 11.7%,  #3 2006,  9.2%  #4  at 7.5%: 2005-2009-2010-2011- 2013, #5 2012,  6.7%,  #6 2017 4.2%, #7 2004-2007-2008-2014, 3.3%, #8 2002,  1.7% ,  #9 2003 0.8%. 

    Although sun disk vertical dimensions data trends closely match Northern Hemisphere temperatures ,  this year may be an exception similar to 2014,  largely because the playing field where the data was retrieved has drastically changed,  namely because there was so much snow over wide expanses.  Arctic snow cover was predictably often 10-20 cm thick in the past,  not much,  after all the Arctic has less precipitation than vast deserts.  The spring time land and ice scape usually was a mix of land and ice interspersed by snow.  2017 went against the norm in a big way.  Local Barrow Strait shore sea ice should be about 200 cm thick by end of April,  or end of accretion date. It is only 140 cm was so for a month.  A lot of snow acts like sea ice proxy,   it is currently a 60 cm  insulation  which replaced sea ice.  Since the local  physical landscape changed,   I must change my approach to the meaning of sun geometry apparently changing course.    

  Sea ice "First Melt" (FM) day the latest since observations began

   Spring First Melt occurs when Sea ice horizon goes down to the Astronomical Horizon for the first time since it formed,  the air temperature immediately above becomes isothermal,   air layers right above  this isotherm may be warmer causing some illusions.  

                                                      2017 April 25

                                                     2016 March 9, 

                                                   2015 March 26,  

                                                      2014 April 10, 

                                                   2013 March 23, 

                                                   2012 March 17, 

                                                    2011  April 15,

                                                    2010 March 19. 

     But with the thinnest sea ice ever,  the meaning of 2017 "First melt" has been hijacked 

by too much snow on top of sea ice,  much more than 2016,  more or less double.  Snow replacing sea ice giving dissimilar optical effects is a new  feature,  from the unusual flood of snowflakes stemming from warmest winter in Arctic history.    What we know about FM predictive power is related to the start of the melt season,   since too much snow halted accretion for more than a month,  the melt season also was delayed but from a thinner point,  when this snow disappears in June,  there will be huge water ponds, the ice will vanish extremely quickly then after.  So the later first melt date would have significance if the sea ice thickness was more average in thickness.  Otherwise,  on a larger Arctic Ocean scale,  if thick snow is laced all over the Arctic as it appears to be so,  the illusion of a normal sea ice melt rate will last until severe sudden disintegration.  

Few days after FM,  this strange unusual horizon line look 

  The jagged sea ice horizon usually happens at the Astronomical Horizon,  it becomes distorted,  by excessive heat in the air a few meters above sublimating snow,  the gaps are likely due to various snow layering thickness,  ice ridging, some old  vs new ice,  sun shade,  describing diverse highly localized albedos.  

   Stratospheric humdrum

    A cloudy Arctic should have cooled the stratosphere,  but the warmest winter in Arctic history flat lined on the average trend,  this is uncommon.  

ENSO appears to trend neutral

   ESR ENSO marks no definite trend, much like a stall especially with the Sea Current,  a trending La-Nina marked the spring time Arctic sky in 2016 conversely a very cloudier Arctic winter coincided with El-Nino trending.  

     Northern Hemisphere projection 2017:

      Coldest atmospheres literally swerve the weather dominating events,  knowing where they will be is key in making a good projection for 2017 main events:

 April-May 2017 (sketched in April)

   The Coldest air in the Northern Hemisphere has 3 cells,  cell #1 and 3 are coldest,  #2 warmed first.

The already dominant Antictyclone over the Beaufort sea is greatly enhanced stable,  Cyclones from the North Atlantic split towards the Urals and the North Pole. The sub polar jet already is high in Latitude be cause over all Temperate temperatures are high.  We have conundrum of Normal Arctic 

temperatures over land, warmer over Ocean as well.   

   June-July:

 The North American- Greenland Cold Temperature cell will dominate as a normal Arctic summer,  this should continue the stagnation of Anticyclones over the Beaufort Gyre,  drier Greenland air will mix along with the clockwise flow making it more stable.  Pacific Cyclones will intrude end of July.  North Atlantic Cyclones will split directions between The Atlantic and Russian Urals,  making the Arctic Ocean High stronger.

    August September

  As the last standing Cold cell lingers well North,  Northern Canada will be wetter ,  Lows will mix it up and take turns standing over the Beaufort High,  North Atlantic High will show up more often.  The damage done in July by persistent Gyre High will be finished off by Pacific and Atlantic Lows.

This will cause a great deal more scattering of sea ice. 

Hurricanes and Tornados

      There is no reason to believe that Tornados will be more frequent than average,  there is a colder atmosphere than 2016 , but it is largely confined to the High Arctic Troposphere,  its effect largely nullified in the warmer stratosphere without any greater high speed laminal wind formations as what made 2011 prediction successful.  The Stratosphere is unusually normal,  the very Cold at center -80 C Polar Stratospheric Vortex lasted a very short time,  barely made a high speed spin around the Pole compared to other more prominent years.  However heat contrasts will exist at the higher latitudes, perhaps displacing tornado alley Northwards.  Hurricanes should be less frequent because the Sahara will be especially hot this year, its sand dust greatly affects   Hurricane formations .   Typhoons should be normal in numbers as with a Neutral ENSO season, since  I have not seen nor detected  any significant ENSO trend. 

Northern Hemisphere temperature prediction 

      In all years since 2004,  this was the easiest thing to do,  since I simply transposed or calibrated Arctic  Sun disk vertical disk gains statistics as a defacto Northern Hemisphere temperature  average.  It worked marvelously well.  But now ,  excess snow on Arctic lands makes it more difficult.  

The colder spring time Arctic Atmosphere should stall NH warming gains or temperatures trending upwards as within the last few years, making 2017 # 3 warmest in history.  

 Sea Ice should be #1 lowest volume and likely lowest extent in history

    Difficult as it may be,  the lowest volume of sea ice at 2017 Maxima,  combined with consistent rapid  sea ice displacement velocities and the huge amount of snowfall stemming from the warmest Arctic winter in history, literally makes it easy for a change,  #1 least volume of sea ice come September, with a bit of a problem with extent predictability,  because sea ice is spread out from continuous daily displacements.  The East Siberian sea  to North Pole "arm" or ice bridge will figure prominent again, but will be eventually wiped out given the Gyre circulation,  made strong last year,  was recently reinforced.  The stable presence of an Anticyclone North of Alaska  is normal when the Canadian Archipelago atmosphere is coldest,  the clouds presence encompassing this anticyclone span is also very normal in spring.  Eventually the temperature dew point spread will widden due to solar warming and the effect of a huge area High over the Arctic Ocean will hit like in 2007.    I would expect record number of melt Ponds -late- from all that thick snow cover.  This will accelerate the melt rapidly,   numerous melt ponds will signal the start of very rapid melting, after seemingly sluggish melt daily rates interspersed with at times great variations caused by the lack of sea ice consolidation.   The North Pole will be partially ice free because pack ice will be moving all over the place.  A good Yacht Captain should be able to make to the Pole though.  

Other parts of the world predictions

    The Okanagan valley  BC will be hot and dry at first then turn quite wet,  Midwest North America will be mostly dry and very hot with clean air from the North except from forest fires,  NE coast of Canada and US cooler wet turning same as Midwest come July.  Finally Western Europe  record high temperatures, not as much as North African records. 

     The summer will linger well into fall,  the fall well into winter again.  With Arctic record snow 

fall mixing sea ice data with floating snow.  

  WD May2-3, 2017

   

   

Arctic Snow sublimation physics is very hard to evaluate, but happens to be another very important reason why snow creates deeper cooling.

~ Mid April top centimeter of compact snow takes about 5 days to vaporize
~ Top 1 cm may have wind polished very thin ice only seen by sun reflections
~ Winter,  importance of inversions

     A mid April day top of snow crust hardened by many days of high winds causing substantial sublimation:

Looks of 40 to 50  cm snow carpet,  near record thickness,  at the South shore of Cornwallis Island Nunavut Canada.  4 or 5 days of moderate at times heavy winds appear to have hardened the snow skin rather than distribute it evenly.  The process is more complex than that,  as this picture suggests,  there is very thin ice over the entire canopy causing a direct reflection of wherever the sun is,  the ice really forms heavily on the thinner snow cover,  where sublimation is stronger,  but here it is not so obvious.  This polished veneer disappears in a few days suggesting it was a very dense crystalline cover.

      Same day. in the dimmer lower direct sun,  there is no reflection on the same slope because the light is less strong,  scattering is spreading out photons more thoroughly throughout a thicker atmosphere,    where at first glance,  ice appears to have formed,  it is again more complex,  a closer look reveals a denser top snow crust or skin. Likely 50 to 60 % hard top, a mix of very fine but compacted crystals,  or a rough precursor to ice.  What happened was intense venting of water vapor by the sublimation process,  the winds caused a vacuum amongst the porous cover which accelerated the vaporization process.   When so, top of skin hardens,  column of snow slightly shrinks causing more sublimation vapor pressure,  a natural version of a cold pressure cooker.

        The great snow cover of 2017 made it difficult to measure sublimation rates,  while windy it snowed as well,  the fields of snow changed shape daily:

  Days of Winds carving the thick snow canopy made for a chaotic surface,  imaging the process which created it.

     There can be several layers of snow crusts in one column,  each crust can be 500 to 600 kg/m3 dense as opposed to the entire column being 400 kg/m3.  Within this top denser crust,  the snow temperature was always colder than standard 2 meter air because of sublimation,  this so happens as as long as there is a snow cover until the sun really is high in the sky.   The solid small snow crystals to water vapor process requires a great deal of energy to happen,  this energy is detected by the temperature drop within or on top of the skin and by conduction on the air immediately above it.  Unfortunately,  sublimation can only be measured  accurately with lab conditions,  the Arctic outside is loaded with varying weather, making sublimation appear different with each possible weather scene,   when in fact it is rather a continuous process.


  Briefly by the numbers,
 
   A 1 cm top of snow column has a density of 500 kg/m3,   there is 5 kg in that layer,    it takes

    3013 (latent heat of sublimation)  w/gr X 5000 gr  = 15.1 million Watts to sublimate it.

      Given a solar constant 1360 w/m2 and given that the atmosphere absorbs  23% ,  albedo on a thick  and dense snow layer  varies between 80 to 90%,

        on a perfect clear April 24 sky day:  5.68 MW/m2 can be absorbed by the top 1 cm skin

But not all of is absorbed,  as with figure 2.23:

http://www.usask.ca/hydrology/papers/Pomeroy_et_al_2001.pdf

      A typical 74.5 degrees latitude North High Arctic day top 1 cm snow may absorbs about 2.84 MWatts per meter square.    Therefore it would take 5.3 days for the top cm to evaporate by direct sun radiation alone, which has been observed as such,  but sublimation heat comes from potentially many other sources,  from the warmer snow,  the warmer air,  back scatter from clouds,  heat from ground or sea ice,  by winds drawing out the heat within the snow or ground column.   It is also very difficult to measure temperature at the surface to air interface due to UV affecting thermistors (coming essay).


   Sublimation is one of the main contributors for near ground or sea ice permanent winter Inversions

     To maintain a loss of temperature of 1 degrees C within the same top 1 cm of dense  crystalline snow, 10,000 watts per square meter would be required,  this is clearly not happening.  I have observed more like a permanent cooling of .1 to .3 C of the air immediately off top of thick snow column,  this means the thickness of snow absorbing heat, rather sublimating,   is very shallow,  vaporization is actually happening in more like terms smaller than a millimeter,  like the shrinking size of the crystals themselves with their micro-surface and total entity vaporize,  if we consider 1 mm surface, meaning 500 grams per square meter,  it would still take about 90 watts per meter square of energy to drop the surface temperature by 0.1 C.  This is what is likely more realistic.

     During spring time, when the ground or ice surface becomes much warmed,  the top of snow sublimation should be stronger.  Thermally speaking this sublimation cooling is eventually overtaken by strong sunshine as observed at the sea ice horizon,  sublimation occurs but there is more external solar forcing masking its signature optical effect.    During the long night,  absent of solar effects,  with no shortwave  radiation,   it would be sensible to believe that top of snow or sea ice temperature would be greater than air right above on most occasions,  especially absent warm air advection,  since the only source of greater heat is from the covered by ice much warmer ocean,  that is not the case,  in fact as soon as sea ice covers sea water completely the entire ocean horizon sustains a higher height than Astronomical Horizon (A.H.) until "first Melt Day",  till well into spring following the long Arctic night :

      High Arctic November 2, 2017,   Northwest Passage pretty much completely frozen, from this moment onwards the sea ice horizon will never lower below Astronomical Horizon.  Here 2.6 Arc minutes above A.H.  .  It is counter intuitive, after all sea ice is less than 30 cm thick,  a lot of heat is escaping from the sea despite the ice shallow sheet.  But there is the process of snow and ice sublimation,  which cools the solid top colder than the air right above, this creates a near permanent inversion causing the horizon to rise.

   at least 1.6 arc minutes above A.H,  nearly 2 dark  months have passed,  the ice is 70 cm thicker than in November picture above this one.  Less radiation escaped to space because of sea ice insulation properties.  Throughout all dark season observations,  not one was at or below A.H.,  all were above.  Indicating a permanent colder top of sea ice than surface air.  This is easier to explain,  there is a colder sea ice layer always maintaining a colder top part,  but that is not always theoretically possible.  Sometimes cold air advection  should overtake a warmer thermal ice imprint,  making surface air colder than top of snow would lower the sea ice horizon below A.H.  ,  this was never observed.  Another reason to posit that snow sublimation always helps maintain an inversion at the interface between ice and air.

     Low surface thermal inversions have a huge impact over weather,  they stop surface moisture from rising reducing cloudiness causing more over all cooling to space,  they create,  no,  they are the reason for winter to exist.  When they vanish it is a sign of summer.   When there is a lot of snow on top of the ground or sea ice,  this literally further cools temperatures,  with solar heat  already reflected back up by very white snow albedo,  also made further colder by snow sublimation.  Although exact temperature numbers about this subject are very difficult to be precise with, a small temperature drop on the surface may implicate a very large over all cooling.  WD April 28, 2017

Astounding sea ice velocities suggest free flowing sea ice never consolidated

   NASA EOSDIS  recent Worldview,  already having Goodbye Waves Upper Right,  signifying heavy melting from easily broken apart sea ice,  similar to what we usually see in July or August.  This kind of movement  North of Novaya Zemlya makes coming data days confusing,  as it was ever since the great dispersion of the strongest densest Canadian Pack last September.  We have had this event of a miss-judged magnitude,  the lack of a more stable sea ice pack has triggered more fluid movements always giving open water at some point anywhere over the Arctic Ocean,  this helped warm Arctic Ocean air and "invite"  more Cyclones to linger longer, making the warmest Arctic Ocean in recorded history.   These images reflect this warming.  WD April 8,2017

déjà vu: How Beaufort sea early open water becomes important much later

NOAA HRPT latest visual animation Mainly April 5, 2017.   Beaufort sea water arises from a short winter slumber,  with sea ice measured quite new, about 1 meter thick,  something easily manipulatable by clockwise winds from a small 1030 mb High pressure system.  

2013-2014-2015-2016 and 2017 NASA EOSDIS gives foresight,  we know that 2013-2015 had lesser sea ice Minima extents in September.  We also know 2016 had a very long lasting High Pressure system already raging by April 5.  However, 2017 has the thinner sea ice with similar breaking open sea water as with 2016.  From this vantage point,  we can clearly  make 2017 potentially in league with 2016 early Beaufort sea warming equal or worse by thinner grayer sea ice,  it will not take much wind action to disintegrate the Beaufort pack,  20 degree high solar ray absorption by sea water, likely quite warmer,  does look good for a long boating season .  WD April 6, 2017

Proving snow sublimation being strongly linked to Arctic inversions

~A great deal of energy is necessary to sublimate snow to water vapor.
~This energy likely creates a shallow cooling layer on top of snow surface,  a potential component of air inversions.
~ The process is continuous as long as there is snow,  helps explain the 1st rule of sea ice horizon refraction.

    The first rule of sea ice horizon refraction may as well be called the first rule of snow covered horizons,   a paper from J. W. Pomeroy and E. Brun have directly found top of snow colder than surface air:

http://www.usask.ca/hydrology/papers/Pomeroy_et_al_2001.pdf

   Refer to graphs on page 89.   Where boreal forest top of ground snow or air slightly above it was always colder than surface air.    Although they did not highlight this feature in this paper, this confirms what happens in the Arctic as well.  A boreal forest heavily snow clad horizon should be quite similar to sea ice horizons.

   Remains to identify the reason or reasons.   What creates a skin surface to be colder than either air or what is below a skin surface?  It is counter intuitive,  but sublimation seems to fit the bill, it happens as long as there is snow,  when so there would be an endothermic process involved,  which infers a drop in temperature.

   

   A 5X closer look, March 31 2017  top of Arctic snow,  easily capable of carrying the weight of a person with very little sinking,  the top layer can be as dense as 40 to 60%, implying the presence of ice.  At first mid afternoon top of snow appears dense ,  a few hours of sun seems to spring up vertically elongated snow rods.  The mobile viewing apparatus sank more at the third picture without weight pressure applied,  suggesting and expansion of spacing between the grains  -as seen here - likely in part caused by more water vapor.   Eventually the lower sun rays appeared to influence the return of snowflakes closer together.

  Despite high density snow,  there is a lot of air within a column of snow 1 meter high (3rd picture).  It is a greater source of water vapor than with a shallower layer of snow which gives a warmer subdermal temperature. The top of a snow column is a conduit to air,  of which sublimation occurs continuously.   This requires a lot of energy which should be detected by loss of temperature:

    Throughout the modestly March 31 windy day (10-14 knots),  surface temperatures in blue,  measured by ventilated high precision thermistor,  were always warmer than top of snow skin subdermal (in brown,  equally measured by high precision thermistor).   Just below snow skin was even colder snow,  at least on this day, being more a function of permeation,  or the basic long lasting surface air temperature imprint which varies day by day,  24 hours before surface air had much colder temperatures.  Heat was transferred to the top of snow mainly from the warmer air and from solar radiation fueling  the vaporization of snow to water vapor.

     During no winds clear March 24 afternoon,  the surface temperature difference vs snow skin subdermal was far greater,  by 2 C,  this suggests the best way to measure sublimation is when there is no air turbulence, when thermal mixing is much reduced, allowing for top of snow thermal stratification to be enhanced.  If there was another reason for colder snow skin,  this matter would have been brought out by differing weather conditions,  if there is an esoteric radiative cooling effect, independent of winds,  we would have a similar subdermal skin cooling,  windy or not.    Optical observations also confirm lesser horizon elevation boosts when  it is very windy.

     Applied on the totally white snow covered Arctic scale,  the primary reasons for persistent winter inversions may be caused by the colder ground or sea ice with radiation escaping to space twinned with the sublimation of snow which is a continuous process until the sun is high enough in the sky to warm up top of snow surface, in spite of continuing sublimation,  the extra heat compensates and appears to cancel sublimation cooling, triggering an even greater loss of snow cover without outside temperatures being well above 0 C.   Since the end of 2017 long night,  the Northwest Passage by Cornwallis Island had often a great deal of diurnal ice fog bursts,  which may be explained by the presence of significantly above normal snow cover generating more water vapor,  sublimating vapor adds to Arctic air bromine chemical mix always capped at the near permanent inversion peak temperature usually varying at about 800 meters in late March early April.

     Snow column substitution experiment
        A way to separate a possible thermal radiance cooling effect from sublimation would be to remove a portion of the snow column with a body warm enough to affect the snow skin temperature  immediately above.  I used a 9.3 liter sealed container having a liquid,  mainly consisting water,  made a cavity once filled with snow,  placing  the sealed  container with +27.7 C liquid within,  cover the exposed side of container with snow and measure subdernal skin temperature above an undisturbed  10 cm layer of snow separating the skin and top of container.

         A few meters away from this experiment,  there was the regular high precision thermistor subdermal measurement which regularly showed a +.4 C skin cooling vs surface air,  lower than measurements made March 24 and 31,  because it was very windy, high winds above 10 m/s removed all chances of extensive stratification.   The subdermal temperatures above the container were always equal or slightly warmer than surface air,  the opposite result above a complete snow column.  This implies a warmed top snow layer without a skin cooling effect.   Snow sublimation was highly likely occurring but the heat supplied by the liquid container overwhelmed the drop in temperature required to vaporize snow,  similarly to when the sun is high enough and masks sublimation cooling.
  
WD April 2-4 2017

Consequential applications #2, where is sea ice melting today?

~                                           Ts=Ttsi

       When the mean daily surface temperature is equal to the mean daily top of sea ice temperature,
net melting is occurring.

NOAA daily composites March 23 2017. Skin temperature (left) surface air temperature (right). Barents sea area,  vicinity Franz Josef lands Russia,  there is a band where Ts=Ttsi ,  or Ttsi is a bit warmer than surface temperature,  I usually would consider this as within margin of error from Satellite acquisition, I consider the mean  Ttsi= Ts there.   

Skin temperature areas marked in black where the likely melting is occurring.  

JAXA map,  2 days later,  March 25 2017.  Shows indeed melting where Ts=Ttsi

WD March 26, 2017