Sunday, February 19, 2017

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 "


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


 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


Saturday, February 11, 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.   

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

Thursday, February 9, 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

Tuesday, February 7, 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