Tuesday, January 9, 2018

T***<=Ts duplicated in a Southern location with special instrumentation

Congratulations and salutations to:

C. L. Pérez Díaz , T. Lakhankar , P. Romanov , J. Muñoz , R. Khanbilvardi, and Y. Yu

who wrote and published:

Near–surface air temperature and snowskin temperature comparison fromCREST-SAFE station data with MODISland surface temperature data

~Although not looking for a Skin snow temperature (T***) vs Surface air  (Ts) relation, a very significant paper measured it with great precision using different instrumentation.  At Caribou, Maine USA (46◦ 520 5900 N, 68◦ 010 0700 W)

~ Instruments  : "An Apogee Infrared Radiometer is used to measure snow skin temperature directly by converting thermal energy radiated from the surface in its field-of-view (FOV) to an electrical signal with a response time of less than 1 s (Muñoz, 2014). This process is automated at every 3 min to an accuracy of 0.2 ◦C. The air temperature is measured directly by a Vaisala Temperature/RH Probe through an automated process; also at a 3 min sampling interval with the same accuracy"

      The results from this effort are very important to study:

Caribou Station equipment extraordinary capacity to measure snow surface skin temperatures with accuracy even with the presence of the sun probably offers the proper way to re-equip  mass balance sea ice buoys. 

As we can see,  T***<=Ts ,  snow skin temperature seems indeed always colder than Surface air temperatures even with hourly measurements.  This has been observed optically either over land thoroughly covered by snow or especially at the Arctic Ocean horizon.  The effects of winds, tend to reduce near refraction as well.,  but not always, this has been a subject of great interest.   

Here are a few very important observations and conclusions from the authors (in Italics):

~"Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data"

   I have found that so, in particular if NOAA daily climate composites uses MODIS as their data source.  I established that we can detect a satellite error by using said simple formula T***<=Ts.
~"This leads to the suspicion that maybe ground-measured LSTs in high-latitude regions covered in  snow might not display congruent behavior with satellite readings. Because if the snow temperature satellite readings are far from the real values, this can lead to confusion when trying to predict the occurrence of avalanches or spring floods."

    Suspicion confirmed,  particularly in the Arctic,  this was frequently observed while comparing NOAA daily composites,  while they had skin temperature option available,  a significant problem here, recognized by the authors,  are irregular surface features,  either not covered by snow completely or affected by high vegetation,  trees for instance.

~Near-surface air temperature tends to affect the snow skin temperature directly, although the latter’s fluctuations are not as drastic (Walsh et al., 1985). The record shows that the winter of 2013 was the coldest of the two (hourly lows of −26 and −36 ◦C in late January for T -air and T -skin, respectively). However, it cannot be ruled out that it is possible for the near surface air temperature to be colder than the snow skin temperature at particular times throughout some winter days, but not common on a daily average basis."

    While using much simpler instrumentation and a different technique altogether,  the latter assumption:  "However, it cannot be ruled out that it is possible for the near surface air temperature to be colder than the snow skin temperature at particular times throughout some winter days",
has never been measured with more primitive method, unless the ground surface has a mix configuration of snow and exposed land,  similar to sea ice mix with open water,  which gives a different horizon height."Near-surface air temperature tends to affect the snow skin temperature directly, although the latter’s fluctuations are not as drastic" ,  this has not been observed here in the High Arctic, surface temperatures  and skin temperatures vary in tandem almost if not instantly, sometimes skin temperatures vary independently while surface temperatures do not and vice-versa.  If the authors rather implied that very near the skin of snow air temperatures may be colder than top of snow,  I do not believe so,  but the temperatures can be equal.

Self published related articles:

WD January 9, 2018

Thursday, January 4, 2018

Direct Causal link between ENSO index and Snow extent version 2017-2018

~ Winter Northern Hemisphere Cloud seed theory is :  During El-Nino or especially trending El-Nino more snow,   During La-Nina or especially trending La-Nina less snow

~ It is ecstatic to discover how small this planet is. 

  Proof you ask?

None better than show the facts:

  We note this table from most expansive break down on current ENSO expose (must read here),
look at 2016 brief continuation of El-Nino especially during winter.  Then a downturn to La-Nina from June onwards with a pause in trending during winter 2016-17,  which had significant implications in many parts of the world, then back to trending La-Nina end of 2017.  It means that the trending part is a or the most important aspect.  ENSO reached LA-Nina during the summer of 2016 (when only there is a very small snow signal possible) , however spring 2017 had small upward warming,  which meant more clouds,  which in retrospect affected the entire spring summer season.  And now perhaps the real La-Nina backlash from strong 2014-2016 El-Nino will really show up. 

    So basically if we use the said theory,  there would be more snow in 2016-17 than 2017-18,  lets look

Beginning of winter 2016-17 in light green had indeed  more snow on the ground,   2017-2018 less .   I believe the same can be said with previous winters,  except this graph (taken here) etchings are hard to distinguish.  2011-2012 appears to be lowest which makes sense.  Note the breaking to less snow extent trend starting November 2017 mimicked identically with ONI cooling in table seen just above.  Finally, late winter 2015-16 (I colored matched the outlying lone lowest snow extent in March) had very significant drop in extent , from very high to lowest, exactly when 14-16 El-Nino was ending and substantially trending La-Nina .  WD January 4 2018.

Wednesday, January 3, 2018

Winter 2017-2018 smaller Arctic Polar Vortex Vortices make it warmer for most places except one colder area at once

~The smaller and colder the CTNP vortices the more unstable they become.
~Moving Southwards cold vortices are not a sign of cooling, quite the opposite,  they are
symptoms of a warmer world.
~We now have a climate system which makes modest cyclones very important  in rearranging
   Global Circulations within a few days.

World News flash! it is only colder in about 2/3 of North America at present:

NOAA temperature anomalies are not exactly announcing the beginning of a new ice age,  but if you live in North America you might think otherwise.  Note East of the Rockies coldest surface temps,  not exactly unexpected as written in previous article,  the lack of snow on the ground at midwinter is very conducive for a deeper cooling.  The good news is ,  a significant area of colder atmosphere is not necessarily stable,  and can move away or fade rapidly in especially a warming world:

 Note the Polar Vortex is the entire counterclockwise circulation starting in orange Northwards,  which has cold air vortices within:

NOAA daily composites at 600 mb,  this is where the temperature represents the entire Troposphere.  We see in deeper purple the coldest atmospheres which morph quite a lot,  it gets disrupted by mainly wrm air advection fom moving Northwards Cyclones.  It is not quite exactly a world wide cold winter.

Slowing down the previous animation you can read why a warmer planet has unstable less pervasive colder air ,  but can have serious events of deep freezing even though the rest of the world does not: 
Currently only North America has a deep surface freeze,  this can change quickly,
the smaller the coldest atmosphere (with respect to the size of the rest of the world) the faster its change in spacial distribution and the greater the temperature extreme variances. But this year has 2 main coldest vortices which tend to reform.  Reminds me of hurricane eye wall replacemens.
They are  Canadian Arctic Archipelago and NE Siberia,  both are vulnerable to small weather events, morph rather quickly,  distort along the warm air zones given by the Atlantic and Pacific.  Central Russia and Alaska have had most fascinating warming because there is not enough winter to spread around.  WD January 3,2018