on June 20 will go down in the history of the Yakut small town of Verkhoyansk: he was not only the hottest day in June, but renewed the annual absolute maximum. The thermometer reached the mark plus 38 – an absolute record in the Yakut Arctic was close to Moscow. But, on the other hand, the previous record of 1968 was just seven tenths of a degree below. So, a strong heat even in the Arctic circle isn’t really a miracle for Yakutia.
This is a typical manifestation of sharply continental climate, which is well seen if to compare Verhojansk with Murmansk, located approximately on same geographical latitude.
the Difference between the typical daily temperatures in winter and summer in Murmansk does not exceed 20 degrees. And in Verhojansk he is one of the biggest on Earth and is equal to 63 degrees. The summer in Verhojansk is noticeably warmer than in Murmansk: in the afternoon there is usually 20-22C, and almost every summer heat up to 30 degrees, however, usually in July.
However, the bare statistics suggests that the observed heat center over Yakutia is particularly bright. On the vast territory of the air temperature by 10-15 degrees above normal.
the Reason the Yakut of records hidden in the peculiarities of the atmospheric circulation this summer. Over Western Siberia is located the cold cyclonic vortex, but over Yakutia stretches huge warm anticyclone, which can be traced to a height of 7-8 kilometers. This giant storm has blocked Western transfer, so atmospheric currents describe a giant bend. In the end, in the North of Kazakhstan in autumn is cool, while in the Yakut Arctic — tropical heat.
“If the sky is clear, without clouds, just a few days of such weather, and the temperature of the surface reaches maximum values. Such a situation happened, and it is important to understand how changing atmospheric circulation under global warming. Many studies indicate that the probability of such a long running- period modes, long-lasting anticyclones in the middle latitudes of the Northern hemisphere will increase,” — said Vladimir Semyonov, Deputy Director of the Institute of atmospheric physics named after A. M. Obukhov of RAS, head of laboratory of climatology Institute of geography Russian Academy of Sciences.
to understand the cause of these anomalies, we need to understand the principles of atmospheric circulation in temperate latitudes. Imagine a cut through the lower part of the atmosphere from the Arctic to the tropics. In the North dominated by cold air masses, and in the South – warm. Warm air has a greater volume, so the pressure in it falls with height more slowly than in the cold. The result is formed thicker in the atmospheric pressure differential that forces air to flow from South to North.
On the rotating Earth, these currents are turned on the East. Since forming the Western transfer in which, like whirlpools in the river, constantly are born and die cyclones and anticyclones. But if the contrast in temperature between the Arctic and the tropics decreases, the Western currents in the atmosphere can weaken. And then formed a gigantic and slow-moving waves, and they cause major temperature anomalies.
Decrease the contrast of temperature between the Northern latitudes and the tropics largely due to the warming of the Arctic, which in the last 50 years is extreme pace. In most parts of the planet have warmed more than 1.5 degrees, while in the Arctic 3-3. 5. More intense warming over the Northern seas due to the fact that here due to the cold surface of the weakened convective mixing of the atmosphere. A great contribution to the warming gives the melting sea ice.
So one of the reasons for temperature records in the North of Yakutia can be abnormally warm Arctic, which provokes the formation of blocking anticyclones, and long-lived positive temperature anomalies, especially in summer.
There is reason to believe that in the future these phenomena will be repeated more often, which primarily threatens the intenewnym thawing of permafrost and increased frequency of wildfires.