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Abstract

The objective of the study was to determine multi-annual changes and variability of occurrence of cold spells in summer and warm spells in winter on Spitsbergen in the period 1976–2016, and circulation conditions of their occurrence. Cold days in summer were defined as days with mean daily air temperature lower than temperature corresponding to the 10th percentile from daily temperature, and warm days in winter as days with mean daily air temperature exceeding the 90th percentile from daily air temperature. The research showed a statistically significant increase in mean air temperature, the rate of which in winter was more than four times higher than in summer. The observed warming translated into a decrease in the number of cold days in summer (-2.5 days/10 years in Svalbard Lufthavn and -1.3 days/10 years in Ny-Ålesund) and an increase in the number of warm days in winter (2.7 days/10 years in Svalbard Lufthavn and 2.4 days/10 years in Ny-Ålesund), and warm and cold spells related to the frequency of such days. The rate of the changes was higher in Svalbard Lufthavn than in Ny-Ålesund. The occurrence of cold days and cold spells was particularly related to the advection of air masses from the north-western sector. The occurrence of warm days and warm spells was related to the advection of air masses from the south-west.

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Authors and Affiliations

Arkadiusz M. Tomczyk
ORCID: ORCID
Ewa B. Łupikasza
Sebastian Kendzierski
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Abstract

Significant increasing trends in the air temperature were found both in the surface station of Svalbard Lufthavn and in the low-tropospheric temperature field over the Atlantic Arctic. The variability in temperature, as well as the multiannual trend, is at least three times bigger in the winter months than in summer. An attempt was made to explain the high day-to-day variability in the winter air temperature by the daily variability in the regional pressure field and circulation conditions. Six regional-scale circulation patterns were found by applying the principal component analysis to the mean daily sea level pressure (SLP) reanalysis data and their impact on the low-tropospheric air temperature variability was determined. A bipolar pattern, with a positive center over Greenland and a negative center over the White Sea, dominates in the region and strongly influences the air temperature field at 850 hPa geopotential height (correlation coefficients up to –0.65). The second pattern that impacts the temperature field in the Atlantic Arctic is the one with a center of action over Svalbard (mostly a low-pressure center in winter), strongly influencing the air temperature over the Barents Sea. The remaining circulation types, explaining only 5–8% of the total variance of the SLP field each, do not modify significantly the air temperature at 850 hPa geopotential level over the Atlantic Arctic, and none of the circulation types seems to influence the multiannual temperature trends.
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Authors and Affiliations

Ewa Bednorz
1
ORCID: ORCID
Arkadiusz M. Tomczyk
1
ORCID: ORCID
Bartosz Czernecki
1
ORCID: ORCID
Miłosz Piękny
1

  1. Department of Meteorology and Climatology, Institute of Physical Geography and Environmental Planning, Adam Mickiewicz University, B. Krygowskiego 10, 61–680 Poznań, Poland

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