Przybylak Arctic Winds

Winds, as we know, are the result of both large-scale and synoptic-scale atmospheric circulation. !n addition, local factors such as geography, orography, and topography (altitude and relief) can sometimes significantly influence the direction and speed of winds (Rae 1951; Wagner 1965; Markin 1975; Maxwell 1980, 1982; Ohmura 1981; Pereyma 1983; Wojcik and Przybylak 1991). There is a paucity of scientific literature describing winds in the Arctic in general. Some information may be found in the following sources: Mohn 1905; Sverdrup 1933; Dzerdzeevskii 1941-1945; Pettcrssen et al. 1956; Prik 1960; Gaigerov 1962; Stepanova 1965; Vowinckel and Orvig 1970; Sater et al. 1971; Maxwell 1980, 1982). However, the best sources of information about winds in the Arctic are two atlases (Gorshkov 1980 and Atlas Arktiki 1985).

in winter, the "polar easterlies" exist most markedly over the Norwegian and Barents seas and in the Pacific region (Figure 2.5). The main air stream over the western and central Russian Arctic flows from the southern sector (Siberian high) and is then directed towards the North Pole. After passing the North Pole vicinity, the air masses leave the Arctic Ocean through the gate between Spitsbergen and Greenland. Greenland, being a very significant orographic barrier, causes quite a sharp turn of air masses flowing from the Pacific and the eastern Siberian region area of the Pole. After crossing the Arctic Ocean, the air masses are directed south-eastwards and flow over the north-eastern part of the Canadian Arctic, reaching the Labrador Sea. From Figure 2.5 some great differences may be seen between the main air streams and local winds. This is especially true for Greenland stations, where katabatic winds prevail.

Mean wind speed in the Arctic is strongly negatively correlated with the magnitude of atmospheric pressure and simultaneously it is also highly positively correlated with the intensity of cyclonic activity. Mean wind speed in January (Figure 2.6) in the regions characterised by low atmospheric pressure and high cyclonic activity (Atlantic, Baffin Bay and Pacific regions) oscillates between 6 m/s and 10 in/s. On the other hand, the regions with high atmospheric pressure and high anticyclonic activity (almost the whole Arctic Ocean and the northern and western parts of the Canadian region) have the lowest wind speeds (4-6 m/s). The highest wind speeds observed in the central Arctic rarely exceed 25 m/s. The maximum wind speeds in the most windy part of the Arctic (i.e. in the Atlantic region) are twice as strong (up to 50 m/s) (Gorshkov 1980). These storm winds are probably connected with vigorous moving cyclones or with such mesoscale phenomena as "polar lows" (for details see the next section).

Figure 2.5. Frequency (in %) of the occurrence of winds from eight main directions (1) and prevailing main air streams (2) in the Arctic (after Atlas Arktiki 1985). Meteorological stations: 1 - lvigtut, 2 - Angmagssalik, 3 - Nord, 4 -Jan Mayen, 5 - Ship M, 6 - Annenes, 7 - Bjomoya, 8 - Indiga. 9 - Malye Karmakuly. 10 - Amderma, 11 - Salekhard, 12 - Mys Zhelaniya, 13 - Ostrov Yedineniya, 14 - Ostrov Dikson, 15 -Dudinka. 16 - Khatanga, 17 - Mys Chelyuskin. 18 - Zilinda, 19 - Tiksi, 20 - Ostrov Kotelny. 21 -Chokurdakh, 22 - Ostrov Chetyrekhstolbovoy, 23 - Markovo, 24 - Ostrov Vrangel, 25 - Uelen, 26 - Nome, 27 - Barrow, 28 - Mould Bay, 29 - Cambridge Bay, 30 - Resolute, 31 - Chesterfield Inlet, 32 - Clyde, 33 - Thule, 34 - Alert, 35 - Upemavik.

Figure 2.5. Frequency (in %) of the occurrence of winds from eight main directions (1) and prevailing main air streams (2) in the Arctic (after Atlas Arktiki 1985). Meteorological stations: 1 - lvigtut, 2 - Angmagssalik, 3 - Nord, 4 -Jan Mayen, 5 - Ship M, 6 - Annenes, 7 - Bjomoya, 8 - Indiga. 9 - Malye Karmakuly. 10 - Amderma, 11 - Salekhard, 12 - Mys Zhelaniya, 13 - Ostrov Yedineniya, 14 - Ostrov Dikson, 15 -Dudinka. 16 - Khatanga, 17 - Mys Chelyuskin. 18 - Zilinda, 19 - Tiksi, 20 - Ostrov Kotelny. 21 -Chokurdakh, 22 - Ostrov Chetyrekhstolbovoy, 23 - Markovo, 24 - Ostrov Vrangel, 25 - Uelen, 26 - Nome, 27 - Barrow, 28 - Mould Bay, 29 - Cambridge Bay, 30 - Resolute, 31 - Chesterfield Inlet, 32 - Clyde, 33 - Thule, 34 - Alert, 35 - Upemavik.

Figure 2.6. Average monthly wind speed (in m/s) in January, April. July, and October in the Arctic (after Gorshkov 1980).

Figure 2.6. Average monthly wind speed (in m/s) in January, April. July, and October in the Arctic (after Gorshkov 1980).

In the course of the year, the maximum anticyclonic activity and the minimum cyclonic activity occur in spring, especially in the Western Arctic. In the area of the greatest occurrence frequency of anticyclones (> 15%) between the North Pole and the northern parts of Greenland and the Canadian Arctic there are no clear dominant wind directions. Simultaneously, mean (Figure 2.6) and maximum wind speeds are the lowest in these areas (< 4 m/s and < 20 m/s, respectively). In stations Alert and Isachsen the frequency of calms was noted in 59% and 32% of all observations, respectively. Southern and south-western winds prevail on the Russian Arctic coast, with the exception of the Chukchi Peninsula. In the rest of the Arctic the main air streams are similar to winter. In the Western Arctic, mean wind speeds rarely exceed 6 m/s. Higher speeds are only recorded in the southern part of the Canadian region and in the Baffin Bay region. As in winter, the strongest winds occur in the southern part of the Atlantic region.

In summer, the main air streams in the Canadian Arctic and over the Norwegian Sea show generally the same pattern as in winter (Figure 2.5). In the northern part of the Barents Sea, south-western and western winds prevail. Further east, in most parts of the Russian Arctic, northern and eastern winds dominate. From the Pacific region the main air stream flows northwards towards the pressure depression around the Pole. Almost from the opposite side of the Arctic (the Greenland Sea) large air streams also reach that depression. This means that there is a marked convergence zone of air streams in the central Arctic Ocean in summer. Wind speeds in this season in the Canadian Arctic and in the Arctic Ocean are mostly slightly higher than in spring (Figure 2.6). On the other hand, in the Atlantic region and in the Baffin Bay region the wind speeds are significantly lower in summer, rarely exceeding 6 m/s. Generally, the distribution of the maximum wind speeds also follows the same pattern.

In autumn, the patterns of distribution of atmospheric pressure and synoptic activity arc roughly similar to those of winter (see Figures 2.2a and 2.2d and maps in Atlas Okeanov). As a consequence, maps showing the distribution of mean wind speed (Figure 2.6) in the Arctic in the seasons analysed are also similar. In autumn, however, wind speeds are generally slightly lower, with the exception of the Pacific region, where the strongest wind speeds are probably connected with greater number of cyclones in this season entering the Chukchi Sea through the Bering Strait. Stronger cyclonic activity also causes greater wind speeds over the Kara, Laptev and East Siberian seas.

Renewable Energy 101

Renewable Energy 101

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