The atmospheric role in the Arctic water cycle: A review on processes, past and future changes, and their impacts

This is the final version of the article. Available from the publisher via the DOI in this record.Atmospheric humidity, clouds, precipitation, and evapotranspiration are essential components of the Arctic climate system. During recent decades, specific humidity and precipitation have generally increased in the Arctic, but changes in evapotranspiration are poorly known. Trends in clouds vary depending on the region and season. Climate model experiments suggest that increases in precipitation are related to global warming. In turn, feedbacks associated with the increase in atmospheric moisture and decrease in sea ice and snow cover have contributed to the Arctic amplification of global warming. Climate models have captured the overall wetting trend but have limited success in reproducing regional details. For the rest of the 21st century, climate models project strong warming and increasing precipitation, but different models yield different results for changes in cloud cover. The model differences are largest in months of minimum sea ice cover. Evapotranspiration is projected to increase in winter but in summer to decrease over the oceans and increase over land. Increasing net precipitation increases river discharge to the Arctic Ocean. Over sea ice in summer, projected increase in rain and decrease in snowfall decrease the surface albedo and, hence, further amplify snow/ice surface melt. With reducing sea ice, wind forcing on the Arctic Ocean increases with impacts on ocean currents and freshwater transport out of the Arctic. Improvements in observations, process understanding, and modeling capabilities are needed to better quantify the atmospheric role in the Arctic water cycle and its changes.We thank all colleagues involved in the Arctic Freshwater Synthesis (AFS) for fruitful discussions. In particular, John Walsh is acknowledged for his constructive comments on the manuscript. AFS has been sponsored by the World Climate Research Programme’s Climate and the Cryosphere project (WCRP-CliC), the International Arctic Science Committee (IASC), and the Arctic Monitoring and Assessment Programme (AMAP). The work for this paper has been supported by the Academy of Finland (contracts 259537 and 283101), the UK Natural Environment Research Council (grant NE/J019585/1), the US National Science Foundation grant ARC-1023592 and the Program “Arctic” and the Basic Research Program of the Presidium Russian Academy of Sciences. NCAR is supported by the U.S. National Science Foundation. We gratefully acknowledge the project coordination and meeting support of Jenny Baeseman and Gwenaelle Hamon at the CliC International Project Office. No new data were applied in the manuscript. Data applied for Figures 2 and 3 are available from the JRA-55 archive at http://jra. kishou.go.jp/JRA-55/index_en. html#usage

Changes in temperature, precipitation and snow cover in the Arctic Sea region, 1981–2010

The results of climatic generalization and analysis of the observation series on air temperature, precipitation and snow cover in the regions of the Arctic Seas and at the stations of the Canadian Archipelago to the north of 70° N are presented for the period 1981–2010. One uses data of meteorological observations at the permanent coastal and island stations and at the «North Pole» drifting stations and data from drifting buoys in the Arctic Basin. Quantitative estimates of the tendencies of change of the considered meteorological characteristics for the last 30 years in the areas of the Arctic Seas and in the Arctic Basin are presented

Seasonal, interannual and long-term variability of precipitation and snow depth in the region of the Barents and Kara seas

Observation data of temperature, precipitation and snow depth have been compiled and generalized climatologically for a network of 38 stations in and around the Barents and Kara seas, for the period 1951–1992. The monthly precipitation totals were corrected for measuring errors, and the correction method is described in detail. The corrected precipitation values show that the annual precipitation in the region ranges from more than 500 mm along the coast of the Kola Peninsula to less than 200 mm in parts of the north-eastern Kara Sea. The solid fraction of the annual precipitation ranges from 70 % in northern parts to 35 % in southern parts. For the period 1951–1992 the analysis indicates decreasing trends in annual values of temperature, precipitation and snow depths in the north-eastern parts of the region

Изменения температуры, осадков и снежного покрова в районах арктических морей за 1981-2010 гг.

The results of climatic generalization and analysis of the observation series on air temperature, precipitation and snow cover in the regions of the Arctic Seas and at the stations of the Canadian Archipelago to the north of 70° N are presented for the period 1981–2010. One uses data of meteorological observations at the permanent coastal and island stations and at the «North Pole» drifting stations and data from drifting buoys in the Arctic Basin. Quantitative estimates of the tendencies of change of the considered meteorological characteristics for the last 30 years in the areas of the Arctic Seas and in the Arctic Basin are presented.Представлены результаты климатического обобщения и анализа рядов наблюдений за температурой, осадками и снежным покровом в районах арктических морей и на станциях Канадского Арктического архипелага севернее 70° с.ш. за период 1981–2010 гг. Использованы данные метеонаблюдений на стационарных береговых и островных станциях, на дрейфующих станциях «Северный полюс» и с дрейфующих буёв в Центральном Арктическом бассейне. Приведены количественные оценки тенденций изменения рассматриваемых метеохарактеристик за последние 30 лет в районах арктических морей и в Арктическом бассейне.