January 18, 2013 - PLANET EARTH
- Sudden stratospheric warming has split the polar vortex in two. The
polar vortex, which forms and deepens as the atmosphere loses heat to
space in the darkness of the long Arctic winter night, was split in two
by massive heating from below. A series of intense storms in the far
north Pacific intensified a very long wave in the lower atmosphere.
Energy on that planet sized wave went upwards from the lower atmosphere
around the Himalayas and Tibetan Plateau and broke into the
stratosphere, causing major sudden warming. It rapidly reversed the
strong cyclonic winds in the stratosphere around the pole, creating a
central dome, breaking the vortex into two smaller vortices. We can see
the splitting by making a map of the heights a weather balloon rises to
to reach the very low atmospheric pressure of 50 mb. A standard
atmosphere is 1013mb.
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| The polar vortex was intact at 50 millibars (heights in m) on January 1 to 3. NOAA. |
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| The polar vortex had broken in two (50millibar heights in m) on January 10 to 13. NOAA. |
Major stratospheric warmings have taken place, on average, every other
year over the past 50 years. The physics of these warmings is very
complicated. Since 1998 these warmings have been more frequent and
earlier in the winter. Previously, major warmings typically happened in
February. Over the past decade they have happened in December and
January, but this one is exceptional on all counts. This stratospheric
warming is apparently the strongest ever observed in the first half of
January according to the NOAA figure. No one knows why the number of
major warmings is increasing but a correlation has been with positive
sea surface temperature anomalies and the active phase of the solar
cycle. This year the sun is active and there are large positive sea
surface temperature anomalies in the north Indian ocean and the
north-west Pacific.
On average, during 1957/58–1990/91, MWs occurred only once every two
Arctic winters (e.g Bancala et al. ´ , 2012; Cohen and Jones, 2011;
Andrews et al., 1987). Conversely, no MW occurred in 9 consecutive
winters from 1989/90 to 1997/98, except a minor warming in early
February 1990 (Manney et al., 2005). However, there were 7 MWs in 5 out
of the 6 winters from 1998/99 to 2003/04. The winter 1999/00 was
unusually cold but each other winter was prone to MWs... Furthermore,
two MWs were observed in 1998/99 and 2001/02...This warming sequence
continued and there were 5 MWs in 5 winters again in 2005/06–2009/10...
Many of the MWs in recent years have been atypically early
(December/early January) compared to those found before 1990s, which
were observed mostly in February.
Major stratospheric warming events like these have a large impact on the
weather. The warm air in the stratosphere radiates heat and sinks, then
warms as it sinks by compressional heating. It causes a mound of
relatively warm air and high pressure to develop around the pole. Cold
air is pushed away from the pole, in this case under the two vortices.
In the Pacific ocean the dynamic interaction of the cold air with
abnormally warm water off of the northeast coast of Japan developed one
of the strongest north Pacific storm in many years with a central
pressure of 932mb, as low as a major hurricane, and modeled wave heights
of over 60 feet.
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| At its most
intense point, the storm had an air pressure reading of about 932 mb,
roughly equivalent to a Category 4 hurricane, and more intense than
Hurricane Sandy as that storm moved toward the New Jersey coastline in
October. (In general, the lower the air pressure, the stronger the
storm.) The storm's central pressure plunged by 48 to 49 mb in just 24
hours, making it one of the most rapidly intensifying storms at a mean
latitude of 34°N since 1979, according to a data analysis by Ryan Maue
of Weatherbell Analytics. On Tuesday, the storm spanned a staggering
1,440 miles, according to David Snider, a meteorologist at the National
Weather Service in Alaska. That's equivalent to the distance between
Denver and New York City. NERC Sat. receiving station Dundee Uni.
Scotland. |
The swell will generate massive waves on the north and west shores of
the Hawaiian Islands. NOAA's outstanding surf forecaster, Pat Caldwell
is forecasting 24 foot wave face heights without the amplifying effects
of refraction by the sea floor. In surf spots refraction can double
these wave heights. 50 foot wave faces are possible on Friday at outer
reefs on Kauai and Oahu.
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| Ocean prediction center. |
The vortex over north America has been pushing cold air over the United
States. Multiple outbreaks of Arctic air can be expected over the
eastern half of the U.S. and Canada over the next ten days. A winter
storm developing now over the southern Appalachians is forecast to bring
snow to the DC area tomorrow afternoon. Then the storm is predicted to
intensify over the north Atlantic. The amplifying energy of the
southward displaced vortex over north America are forecast by the GFS
model to make the storm "bomb" to a 944mb low south of Greenland. Huge
waves are forecast to hit the Atlantic coast of Europe early next week.
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| U.S. Navy WWIII model. |
In February 2009 a major stratospheric warming and polar vortex
splitting event occurred unleashing cold air into the eastern United
States and Europe. London, England had its heaviest snow in 20 years. NASA's Earth Observatory has a high res video of the event and a plain language description of what happened. - Daily KOS.
