The Interior Arctic Region

The horizontal gradients of meteorological elements here are the lowest in the Arctic. However, some differences in pattern distribution of these elements exist, which allow a distinction to be drawn between two separate sub-regions: the sub-Atlantic and the sub-Pacific (Prik 1971; Atlas Arktiki 1985).

The sub-Atlantic area quite often falls under the influence of the North Atlantic cyclones and therefore the temperatures here are higher than in the sub-Pacific sub-region, where anticyclones dominate. The winter temperature varies here from -24°C to -26°C in the southern part to about -32°C near the Pole. Absolute minimum temperatures can drop below -50°C. According to the map presenting the mean annual fields of sea level pressure (Serreze et al. 1993), southerly winds dominate in this sub-region. Wind speeds are significantly lower here than in the Atlantic region and oscillate between 5.5 m/s and 6.5 m/s but their range of variation is considerable: from extremely weak to very strong. Cloudiness in winter is significantly lower than in summer and ranges from 60% in the southern part to about 50% near the Pole. Precipitation is very frequent but its intensity is light. Monthly totals do not exceed 10-15 mm, and yearly 200-250 mm.

The sub-Pacific sub-region, due to the dominance of anticyclone circulation, has a more severe climate in winter than the previous sub-region. Temperatures are, on average, 6-10°C lower and their spatial changes are very small. Minimum temperatures generally do not drop below -53°C while maximum temperatures do not exceed -3°C to -5°C. The dominance of anticyclones results in the occurrence of unstable and weak or moderate winds. Their speeds are lower here than in the sub-Atlantic sub-region and oscillate between 4.5 m/s and 5.5 m/s. Also there is less cloudiness and precipitation here.

In summer, the meteorological regime is similar in both the sub-regions. The mean temperature approaches 0°C because it is limited by the melting process. The range of temperature oscillates between -6°C and 4-6°C. The small daily contrast of incoming solar radiation (polar day), very high cloudiness (80-90%), and the melting of snow and sea ice result in daily variations of temperature being exceptionally low (on average 0.4°C to 0.5°C). The wind directions are very changeable and speeds are not particularly high (4.5-5.5 m/s). Storm winds (> 15 m/s) are very rare in the summer months and, according to

Prik (1971), only two to five cases every 10 years are observed. Cloudiness is exceptionally high (about 90% of cloudy days and only 4-8% of clear days) and occurs mainly in the form of low clouds. Precipitation, although quite frequent, gives small totals because its intensity is very small. A characteristic phenomenon of the summer in the interior Arctic region is the frequent occurrence of fog (25-40%).

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