Scientists describe the reason for the cold winters in the northern hemisphere

MOSCOW, October 9 — RIA Novosti. The solar cycle has a direct impact on climate variability in the Northern Hemisphere — reducing the power of UV radiation in the solar minimum was the cause of an abnormally cold winter in high latitudes in Europe, Asia and North America, climate scientists say in a paper published in the journal Nature Geoscience.

400 years of observations of the Sun indicate that our star is alternating periods of growth and decline of activity, successive after about 11 years. The period of greatest solar activity called solar maximum, minimumsolar minimum.

Sarah Ineson (Sarah Ineson) from the Center for Climate name Hadley in Exeter (UK) and colleagues built a climate model that takes into account fluctuations in the solar cycle and its impact on ocean currents. To do this, researchers looked at data collected by the satellite SORCE over the past seven years.

Solar Observatory SORCE was launched American space agency NASA in January 2003. The station is monitoring changes in the intensity of solar radiation in multiple spectrum — visible, infrared and ultraviolet.

Ineson and her colleagues found that current climate models overestimate the effect of ultraviolet radiation during solar minimum is about 4-6 times in comparison with the data SORCE. As the climate scientists, UV is the main source of the "heating" of the lower atmosphere of the Earth. Even small changes in the power of radiation lead to serious consequences for the climate and the formation of the ozone layer that protects living organisms from the action of cosmic rays.

The authors have introduced variations of UV radiation as an additional parameter in the global climate model HadGEM3 and tracked the climate change over the 80 years. This model takes into account the interaction between ocean currents and air masses, including the so-called, and the North Atlantic Oscillation (NAO) — the main "conductor" weather in the Atlantic.

According to the model Ineson and her colleagues, the air pressure in the northern regions of the Atlantic and the Pacific in the fall and winter is growing, while the mid-latitudes, it falls. Much the same is happening in reality, during the so-called "negative" phase of the NAO.

Because of the difference in pressure flow of warm water in the North Atlantic is reduced, resulting in air temperature over north-eastern Europe and northern Asia decreased to abnormal values. In addition, climate researchers have fixed a small climate change on the northern coast of Canada and in the southern regions of the United States, but they had practically no effect on the global climate system.

According Ineson and colleagues, such anomalies are generated in the middle atmosphere — mesosphere and stratosphere in the tropics, where the air temperature drops by 1-2 degrees Kelvin in the transition from solar maximum to minimum. Relatively cold air masses transported altitude meridional winds in the North Pole. Because of this, the normal circulation of winds in the polar regions is disturbed, and average daytime temperatures of late autumn and winter are somewhat reduced.

Climatologists believe that their model and new data from the SORCE satellite will help other climatologists refine long-term predictions of climate variability that are not "evolved" because of inaccuracies in the estimation of the UV radiation during solar minimum.

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