January 16, 2013. Circumpolar vortex that is formed and evolves as the atmosphere loses heat into space during the long polar night, was divided into two parts, a significant warming in the lower layers. A series of powerful storms in the North Pacific has caused a long wave in the lower atmosphere. The energy of the planetary-scale waves rose higher in the Himalayas and the Tibetan Plateau, and broke into the stratosphere, causing a sudden stratospheric warming (WWW). This dramatically changed the direction of cyclonic winds around the pole and broke the polar vortex into two vortices smaller.
See also: Is there a relationship between the observed cold weather and sudden stratospheric warming?
We can observe this distinction, reaching a height map, which rise weather balloons, to achieve a very low atmospheric pressure of 50 mbar. Normal atmospheric pressure is 1013 mbar.
Notable stratospheric warming occurred, on average, every two years for the past 50 years. The nature of this warming is very complex. Since 1998, they have become more frequent and earlier in the winter. Previously, a notable warming occurred mainly in February. In the last ten years they took place in December and January, but this thaw exclusively in all senses. It is obvious that this warming is the most powerful of all that have been observed in the first half of January, according to the National Oceanic and Atmospheric Administration United States (NOAA). No one knows the reason why a growing number of WWW, but the correlation was conducted with positive temperature anomalies on the surface of the oceans and active phases of the solar cycle. This year, the sun is active, and there are significant positive temperature anomalies in the North Indian Ocean and on the north-western Pacific Oceans.
Dynamics of activity in recent winter periods shows that the frequency of the WWW in the Arctic region increases (
On average, from 1957/58 to 1990/91 GSP took place every two Arctic winters (source: Bancala et al., 2012; Cohen and Jones, 2011; Andrews et al., 1987). At the same time, 9 were observed warming winters with 1989/90 to 1997/98., Except for a slight warming at the beginning of February 1990 (Manney et al., 2005).
Be that as it may, from 1998/99 to 2003/04. 7 happened warming winters in 5 of 6. Winter 1999/00 was extremely cold, but the rest were subject to the GSP. Moreover, double warming have been recorded in the winter 1998/99 and 2001/02. This trend has continued in the period from 2005/06 to 2009/10, it was noted five warming over five winters. Many of the warming in recent years have been uncharacteristically early (December / early January), especially in comparison to the GSP until 1990, which were observed mainly in February.
Strong stratospheric warming, like this, have a huge impact on the weather. Warm air in the stratosphere loses heat and falls, then heated again due to compression. Because of this, a barrier is relatively warm high pressure air around the pole. The cool air is expelled from the pole in this case, two vortices. In the Pacific, the interaction of cold air from the abnormally warm water from the north-east coast of Japan has caused the emergence of one of the strongest North Pacific storms in recent years, with central pressure 932 mbar, and waves up to 18 meters high.
At the peak of the intensity of the pressure in the center of the storm was 932 mbar, which is equivalent to grade 4 hurricane — it's more than a hurricane was named Sandy, when he went to the coast of New Jersey in October. (In general, the lower pressure, the stronger storm). Pressure in the center of the storm has fallen sharply in the 48-49 mbar for only 24 hours, making this storm one of the most rapidly at 34 ° north latitude for the period since 1979, according to the analysis of Mo Ryan Weatherbell Analytics.
According to David Snyder, a meteorologist from the National Weather Service office in Alaska, on Tuesday storm stretched out already at 1440 miles. This is equal to the distance between Denver and New York.
The storm will cause strong waves on the north and west coasts of the Hawaiian Islands. One of the best experts on the surf forecast from NOAA predicts the appearance of wave height of 7.2 meters (excluding the multiplier effect of refraction from the sea floor). Wave height of 15 meters are possible on Friday at the outside of the reef islands of Kauai and Oahu.
Whirlwind in the North American cold air pushes in the direction of the United States. In the next few days are expected to multiple breakthroughs Arctic air in the eastern United States and Canada. Winter storm formed now the southern part of the Appalachian Mountains and the forecast will bring snow in Washington County to the next noon. Further, it is expected to grow in the North Atlantic. Additional energy is shifted to the south of the vortex over the north of America, according to the model GFS (Global Forecast System), will lead to "explosive" increase to 944 mbar storm over southern Greenland. At the beginning of next week predicted big waves on the Atlantic coast of Europe.
In February 2009, a strong stratospheric thaw and the separation of polar vortex caused a cooling in North America and Europe. In London, fell the strongest in 20 years snow.
Translation: Anastasia Antoshkina