Daily temperature measurements from six meteorological stations along the coast and fjords of western Spitsbergen have been digitized and quality controlled in a Norwegian, Russian and Polish collaboration. Complete daily data series have been reconstructed back to 1948 for all of the stations. One of the station's monthly temperature series has previously been extended back to 1898 and is included in this study. The long-term series show large temperature variability on western Spitsbergen with colder periods in the 1910s and 1960s and warmer periods in the 1930s, 1950s and in the 21st century. The most recent years are the warmest ones in the instrumental records. There is a positive and statistically significant trend in the annual times series for all of the stations; however, the strongest warming is seen in winter and spring. For the period 1979Á2015, the linear trends range from 1.0 to 1.38C/decade for the annual series and from 2.0 to 2.38C/decade in winter. Threshold statistics demonstrate a decrease in the number of cold days per year and an increase in the number of warm days. A decreasing inter-annual variability is observed. In winter, spring and autumn, the stations in the northernmost areas of west Spitsbergen and in the innermost parts of Isfjorden are the coldest ones. In summer, however, the southernmost station is the coldest one. To access the supplementary material for this article, please see the supplementary files under Article Tools, online.

The effect of the meridional atmospheric heat and moisture transport on the Arctic warming is estimated using the ERA‐Interim reanalysis over 1979–2015. Major influx of sensible and latent heat into the Arctic occurs through the Atlantic sector 0°–80°E between the surface and the 750 hPa level. This influx explains more than 50% of the average temperature variability in the area 70°–90°N in winter with almost equal contribution of both fluxes. Calculations using MPI‐ESM‐MR Earth System model from the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble showed the similar effect of the meridional atmospheric heat and moisture transport and its increase by the end of the century. Mean summer transport in the low troposphere is directed from the Arctic and transfers out the moisture produced by summer melting of sea ice. The major drivers of summer warming are the radiation processes especially downwards longwave radiation.

Citation: Frolov I. E., Ivanov V.V., Filchuk K.V., Makshtas A.P., Kustov V.Yu., Mahotina I.A., Ivanov B.V., Urazgildeeva A.V., Syoemin V.L., Zimina O.L., Krylov A.A., Bogin V.A., Zakharov V.Yu., Malyshev S.A., Gusev E.A., Baryshev P.E., Pilgaev S.V., Kovalev S.M., Turyakov A.B. Transarktika-2019: winter expedition in the Arctic Ocean on the R/V "Akademik Tryoshnikov". Problemy Arktiki i Antarktiki. SummaryPreliminary results of the Transarktika-2019 winter expedition in the Arctic Ocean on the R/V "Akademik Tryoshnikov" are presented. The expedition program included studies on meteorology, hydrology, hydrochemistry, hydrobiology, geology, geophysics and an extensive complex of ice measurements in the Northern Barents Sea from the drifting ice and from the ship. During the expedition, it was possible to complete a wide range of tasks. The data obtained comprise a unique material for a comprehensive study of the current state of the environmental conditions in the Barents Sea. This paper highlights the most signifi cant preliminary results of multidisciplinary observations in various environments, which will be further comprehensively analyzed and published in separate thematic articles.Поступила 7 августа 2019 г.Принята к печати 23 сентября 2019 г.Ключевые слова: Баренцево море, геология, геофизика, гидробиология, метеорология, морской лед, океанография, полевые наблюдения, Северный Ледовитый океан.Представлены предварительные результаты зимней экспедиции «Трансарктика-2019» в Северном Ледовитом океане на НЭС «Академик Трёшников». Программа экспедиции включала в себя исследования по метеорологии, гидрологии, гидрохимии, гидробиологии, геологии, геофизике и обширному комплексу измерений ледяного покрова в северной части Баренцева моря с дрейфующего льда и с борта судна. Во время экспедиции удалось выполнить широкий круг задач. Полученные данные представляют собой уникальный материал для всестороннего изучения текущего состояния условий окружающей среды в Баренцевом море. В статье обозначены наиболее значимые предварительные результаты междисциплинарных наблюдений в различных средах, которые в дальнейшем будут всесторонне проанализированы и опубликованы в отдельных тематических статьях.

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