ИСТИНА

The interest to the Arctic has been lately increased due to occurring there quick climate changes, as well as forecasts pointing at the so-called polar magnification of the global warming during the XXI century (Bekryaev et al., 2010). Conclusions of certain publications (Lenton et al., 2008) declare that climate changes in the Arctic reached the threshold values when the irreversible processes can occur and one can expect the complete ice melting in summer. The most important feature of the Arctic climate in the past century is its multiple changes. Periond of warming (1915–1949 and 1971 till now) and cooling (1950–1970) were observed in the global climate, which were more noticeable in the Arctic compared to other latitudes. These climate oscillations (Panin, 2009; Panin et al., 2009, 2015; Panin and Diansky, 2015; Semenov, 2008) are not reproduced in simulations with the IPCC Earth system models based on the coupled models of atmosphere and ocean general circulation (IPCC, 2013), excluding the French model CNRM-CM5 (Météo-France/CNRS and CERFACS) and the German model in the two versions MPI-ESM-MR, MPI-ESM-LR (Mokhov, 2015; Mokhov et al., 2016). Data on temperature measurements and reconstructions in the north polar zone (Panin, 2009) evidence on the significant contribution of cyclic (about 60 years) temperature variations in the Arctic climate. In (Alekseev, 2015; Mokhov, 2015) it was noted that in the temperature intrasecular regional (e.g. in the North Atlantic and Atlantic sector of the Arctic), hemispherical and global changes, as well as in the changes of ice content in the Arctic seas, the variations of periods about 6 decades are noticeably presented, which are typical for the Atlantic Multidecadal Oscillation (AMO), connected, in turn, to the ocean thermohaline circulation. This behavior of the climate change allowed G.N.Panin (2009) to propose the simple approximation of climate changes based on composition of “greenhouse” and “cyclic” effects. The “greenhouse” climate change implies the ones caused by the external anthropogenic or natural (volcano eruptions, change of the Solar constant e t.c.) factors. In turn, the “cyclic” climate changes imply the internal climate oscillations in the joint system atmosphere-ocean-land. At the same time, it was supposed that the main frequency of the strongest cyclic climate oscillations fits to the period of 60 years, and the greenhouse climate changes are presented as a linear trend. It was shown that the boost of Arctic ice melting in the 70’s–90’s of the ХХ century is concerned with the variations in the indices of АМО and intensity of Atlantic meridional circulation. The latter reflects the climate changes in the heat flux from the North Atlantic surface to the Atmospere in midlatitudes. The combined scenario of the climate change assessment is proposed based on the composition of the “greenhouse” and “cyclic” effects. On this basis, the forecast was made of near-surface characteristics of atmosphere circulation for 2010–2071 using the CORE (Datasets for Common Ocean-ice Reference experiments) data for 1948–2009 (Large and Yeager, 2009). Using the data, the prognostic run was made with the OGCM INMOM on reproducing thermohaline circulation and sea ice in the Atlantic and Arctic Oceans for 2010–2071. The interconnections were investigated amongst climate processes of the Nortch Atlantic and Arctic. This approach allows one to describe not only temperature growth due to greenhouse gas emission, but also the climate variability (e.g. observed cooling in 1950’s–1970’s). The proposed combined scenario of climate changes presents the possible cooling in the Arctic and following decrease of the navigation period in the North Sea Route for the next 15-20 years. The main part of the research is done under the financial support of RFBR, grants №15-05-03127, 15-05-07539, 16-05-00534. References: Alekseev G. V. Development and amplification of global warming in the Arctic// Fundamental and Applied Climatology. 2015. № 1. P. 11–26. (In Russian). Mokhov I. I. Sovremennyye izmeneniya klimata v Arktike. [Contemporary climate changes in the Arctic]. Vestn. RAN, 2015, V. 85, № 5–6, P. 478–484. (In Russian). Mokhov I.I., Semenov V.A., Khon V.Ch., Latif M., Roeckner E. Connection between Eurasian and North Atlantic climate anomalies and natural variations in the Atlantic thermohaline circulation based on long-term model calculations // Doklady Earth Sciences. 2008. V. 419. №5. P. 687–690. Panin G. N. On climate changes in polar zones of the earth in the twentieth and twenty-first centuries // Doklady Earth Sciences. 2009. V. 427. P. 397–402. Panin G. N., Vyruchalkina T. Yu., Solomonova I. V. Climatic changes in the Arctic, North Atlantic, the Caspian sea region, and their relationships // Fundamental and Applied Climatology. 2015. № 1. P. 183–210. Panin G. N., Diansky N. A. Climaticheskie izmeneniia v Arktike, Severnoi` Atlantike i Severny`i` morskoi` put`// Doklady Earth Sciences. 2015. V. 462. № 2. P. 217–222. Panin G. N., Solomonova I. V., Vyruchalkina T. Yu. Climatic trends in the middle and high latitudes of the Northern Hemisphere // Water Resources. 2009. V. 36. № 6. P. 743–756. Semenov V. A. Influence of oceanic inflow to the Barents Sea on climate variability in the Arctic region // Doklady Earth Sciences. 2008. V. 418. № 1. P. 106–109. Bekryaev R.V., Polyakov I.V., Alexeev V.A. 2010. Role of Polar Amplification in Long-Term Surface Air Temperature Variations and Modern Arctic Warming. J.Climate, vol. 23, p. 3888–3906. IPCC. 2013. Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, T.F. Stocker, D. Qin, G.K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)] Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp. Large W., Yeager S. 2009. The global climatology of an interannually varying air–sea flux data set. 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