Scientists Are Predicting Polar Vortex To Bring Big Freeze And Coldest Winter For Five Years
Polar vortex enters Northern U.S.
The stratospheric polar vortex is a large-scale region of air that is contained by a strong west-to-east jet stream that circles the polar region. This jet stream is usually referred to as the polar night jet. The polar vortex extends from the tropopause (the dividing line between the stratosphere and troposphere) through the stratosphere and into the mesosphere (above 50 km). Low values of ozone and cold temperatures are associated with the air inside the vortex.
The stratospheric polar vortex shows quite a bit of day-to-day variability. This variability is caused by weather systems or large-scale waves that move upward from the troposphere into the stratosphere. In the left image , we see some undulations along the edge of the polar vortex, but the vortex is generally centered on the North Pole. Two weeks later we see the center of the polar vortex pushed away from the North Pole. On a constant latitude circle, PV values are high in the eastern hemisphere and low in the western hemisphere. This is referred to as a wave-1 pattern . The wave-1 pattern develops in the troposphere and moves upward (propagates) into the stratosphere.
These stratospheric waves are forced by the large-scale mountain systems and the land-sea contrasts between the continents and oceans. During the northern winter, these waves are continuously forming and moving upward into the stratosphere. The waves can “break”, much like the waves on a beach. These wave-breaking events erode the vortex and keep the polar region warmer and ozone amounts higher. Often, parts of the polar vortex are pulled away from the main vortex. The image on the right shows this, where a large piece of the polar vortex was pulled away from the main vortex (green colored material at the bottom of the image). A comparison between the middle and right images also shows a slight contraction of the polar vortex because of these waves.
The polar vortex is a winter phenomena. It develops as the sun sets over the polar region and temperatures cool. During the spring, the sun rises and the absorption of solar radiation by ozone begins to heat the polar stratosphere. This heating eventually causes the vortex to disappear along with the polar night jet. However, this process is helped along by planetary-scale waves that propagate up from the troposphere. This wave event that drives the vortex breakup (or final warming) acts to also increase the temperature of the polar region and ozone levels. We mark the day of the vortex breakup when the winds around the vortex edge decrease below a particular value (about 15 m s -1on the 460 K potential temperature surface).
Health officials have issued a desperate plea to the public, urging them to wrap up warm and turn to pharmacies at the first sign of illness, amid “enormous pressure” on casualty departments. Forecasts suggest could be facing the coldest winter for five years, with average minimum temperatures.
Research has also shown that people with conditions such as heart disease, lung problems including asthma, and dementia are much more likely to die in winter.
Cold indoor or outdoor temperatures increases blood pressure, which heightens the risk of heart failure, kidney disease and stroke.
It also makes the blood more likely to clot, raising the risk of heart attack and stroke, and reduces the lung’s ability to fight off infection.
The senior doctor advised keeping homes warm, with regular hot drinks and meals, and urged people to see their pharmacist at the first sign of health problems.