Thursday, November 7, 2019

Greenland melts more when the flow of sea ice to Fram Strait slows

~Recent summers pressure switchover mechanics have literally saved Arctic sea ice from vanishing more rapidly
~However the real tragedy,  these steady summer Arctic Ocean gyre cyclones bring warm weather melting top of Greenland more.

    First,  winter Arctic High pressures are very cold, they exist over very dry  land or icescapes.  Polar High pressures of summer are warm,  they exist over dry surfaces,  consider a mid July wide open 0 to +4 C sea surface temperature as "dry".    Arctic Low pressures of winter are warm, they usually come from the South and consist of moist very cloudy turbulent air.    Arctic Low pressures of summer are cold,  they can come from the North and readily survive and last longer over a mix of open water and broken up sea ice.  Frozen surfaces are a great contributor to Arctic fog clouds when summer temperatures are near 0 C.  Basic meteorology holds these preceding generalizations consistent for the True North,  not necessarily nearer to the equator.

   This was EH2r's April 2019 projection for June -July, the main circulation overview held quite well.   C1 and C2 are vortices within the Polar Vortex,  the coldest air exists at their respective centers.   Low pressure cyclones location flipped geographically from the a month prior,  from SE to NW of both vortices.  In summer,  coldest air usually hangs out between Greenland and Alaska, partly by the barriers offered by each of these massive topographies,  shading the potential warming influence from the Atlantic and Pacific.    Summer "Switchover" is when the repositioned  Low combats the very existence of the Arctic Ocean gyre,  a clockwise current now faces counterclockwise headwinds (North of Beaufort Sea), the clockwise gyre was  created by months of persistent winter High Pressure hovering (because cold anticyclones thrive during the long cloudier free nights).   Frequently of late,  the summer Low pressure hovering top of the Arctic gyre area can greatly diminish the transpolar current from Siberia to Greenland,  if it lasts long it may even slow, stop or reverse its direction altogether.  These Lows also provides warm advection from the Canadian continent to top of Greenland.   It is here where on the one hand the Gyre summer Low saves the Arctic Basin sea ice but literally helps melt the top of Greenland:

Each respective significant extent melt spikes had one strong thing in common,  the switchover Gyre Low:



From University of Wyoming archives ,  there was a significant Gyre Low pressure North of sea of Beaufort,  during the first large melt over the Greenland ice sheet in 2019,  but on the other side of the Vortex,  the Eastern side ,  there was a High Pressure.  This image is exactly flipped during winter.  Relatively colder weather naturally languishes between Greenland and Alaska year round,  only the pressure configurations change.  It is said,
the Canadian side of the Arctic is usually more humid compared to the Russian side, largely because it is often colder by persistent presence of sea ice spared from direct melting by the influence of massive  Ellesmere Island and Greenland Glaciers.  Now look at 700 mb temperatures on top of Greenland compared to over the Gyre,  near 0 C compared to -15 C,  it was warmer over the massive Greenland ice sheet than above the Arctic Ocean at the same altitudes.  It is unquestionably colder within an Arctic summer Cyclone when top of Greenland melts a lot.  Here the North Atlantic High pressure mixed with a hot continental Canadian atmosphere expanded the number of small to modest in size glacial lakes on top of the Northern Hemispheres largest glacier.

   We seek a consistent pattern confirmation that can only happen during the largest Greenlandic melt extent day of 2019 on about August 2:

Again the atmosphere over the Arctic Ocean  Gyre current is colder by -10  to 0 C during the greatest top of Greenland melting day of 2019.   This largely confirms that the two differing ice sheets do not necessarily melt more in tandem,   but rather require different weather patterns than usually found during mid Arctic summers.  A steady long living cyclone over the Gyre current naturally slows the transpolar Arctic Ocean current which means a significant saving of sea ice volume otherwise to be surely lost to the  very much warmer summer time North Atlantic.

            The only way for summer sea ice to melt entirely would require a rather stupendous change in nature from Greenland's cooling effect.  It is likely possible with a rather huge summer ice lake covering a significant portion top of Greenland,  much nullifying its cooling effect over the Archipelago  region,  then the coldest place in July Arctic would likely be where clouds dominate,  not necessarily above Arctic Ocean gyre current,  the coldest place would vary in locations more often allowing an anticyclone to persist longer over the gyre area,  when so,  the devastation of sea ice should be nearly complete.   WD November 6,2019

Wednesday, November 6, 2019

More numerous Californian wildfires, the Arctic perspective

~ The consequences of ignoring warming Polar regions extends way beyond snow and ice lands.

~We look at one example,  where lot's of people live.

      And so the Arctic just had record lower sea ice extent minimum again, a few weeks after mid September minima being 2nd lowest ever.   In the Arctic, this gave warmer September and October weather with a whole lot more snow and strong blizzards,  nothing to worry the world about.  But further South,  weather patterns have changed not so favorably in some places.  We look further away to the place where wildfires rage,  California, because there is less rain there for a reason:


 2011, 2010 are the best recent years with the least numbers of Californian wildfires, 1982 was an example taken at random.  600 mb temperatures NCEP/NCAR NOAA daily composites for October demonstrate a peculiar Arctic vortex pattern,  squarish roundish with least extended planetary waves.   Of particular interest is the -20 C boundary at or near deep Southern Alaska,  it is in green,  this is the likeliest average location of the Polar jet stream.    We see this green zone being at the British Columbia Alaska coastal border.  Implying a stronger Pacific flow of moist air towards most of western North America,  likely favoring rain.   And there was normal rain in 2010 and 2011 for California.

We look at the wavier 2017-2018-2019 global circulation.   At first glance the average -20 C green line for October looks about the same. Although overall Polar Vortex looks wavier,  showing distinct planetary waves crests,  this is due to a more collapsed Polar Vortex by warming from within.  It is no coincidence,  2017 to 2019 have had record wildfire area outbreaks for California,  costing a profound distressing fortune in lives disrupted materially and psychologically and especially for the environment alike.   Now look again at the 253 Kelvin green line (-20 C).   It was at Barrow Alaska October 2018, at extreme Northern Alaska,  with 2017 and 2018 green line near Anchorage 700 hundred miles further North than 2010 and 2011.  This Northwards repositioning of the Vortex jet stream of course means a weaker Pacific flow for the Californian coastline,  suggesting less fall rains,  as it is and was so (precipitation facts :https://ggweather.posthaven.com/summary-of-california-2017-2018-rainfall-season-ending-tomorrow)

     The Northwards shift of jet stream or the October 600 mb -20 C line movement towards the high Arctic is strictly the result of vanishing sea ice,  during especially about the Arctic sea ice minima,  causing massive warming feedbacks, especially for North Pacific sea surface temperatures.  These fires were very predictable,  because what happens in the Arctic,  does not stay there.  WD November 5 2019