| Due to its geographic location, Galicia is an ideal location for installing wind power. Although meteorologists collate wind data for their provisions, which is frequently used to evaluate the ideals of a specific area, they do not stop cataloguing wind. To this end, they conduct specific studies on behalf of the promoters.
The ruggedness of the land surface and surroundings strongly influences the wind velocity through elements, such as trees, lighthouses and other constructions and, by the terrain itself. In the majority of cases, raw meteorological data underestimates real wind power in the area.
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Velocity frequency distribution pattern
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The development of different atmospheric pressures causes air movements, which, in turn, are a consequence of solar radiation on the land: The atmosphere works as a giant thermal machine within which different temperatures exist at the poles and at the equator, proportioning the energy necessary for atmospheric circulation.
Close to the equator, the lower atmosphere heats and rises, creating low-pressure which draws wind from both atmospheres (the Inter-tropical Convergence Zone). This low-pressure zone is located close to the Equator, slightly orientated towards the northern hemisphere. Within this area, light winds blow from both the east and west, whilst the eastern Trade Winds blow from both sides of the low-pressure zone. These are constant winds that converge around the Equator, extending to around 30º-latitude to the north and south.
High tropical pressures are produced at around 30º in the northern hemisphere. These anti-cyclones settle more to the north during summer and at the Equator in winter. In these areas, winds are very weak, with both the Trade and mid-latitude eastern winds diverging.
Western winds dominate from the high-pressure tropics until near the polar circles where eastern winds predominate; these are less constant than the Trade Winds, both in direction and in intensity. These are further affected by their trajectory through the high and low-pressure nuclei, generally from the east. In the Northern Hemisphere they further become influenced by the irregular continental forms, whereas in the Southern Hemisphere, they are stronger and more constant. In the Polar Regions, the ground level winds trend from a north-westerly direction (in the Northern Hemisphere).
All these zones migrate above the oceans according to the season: towards the north in summer, with a difference of some 10º latitude. Outside the oceans, the dominant winds are less schematic, above all in Africa and Asia.
For most of the year, the Iberian Peninsula falls within the mid-latitude eastern winds, from the northern hemispheric zone in its southern limit. The Iberian winds are very clearly influenced by the seasonal movement of the sub-tropical high-pressure zones that move north during the summer, leaving the Peninsula outside the western wind zone. In this season, therefore, a fall in intensity is produced.
The wind cycle in Galicia is defined by the global atmospheric circulation and by the local effects generated by the land’s orographic complexity, characterised by the following:
- In winter, the arrival of Atlantic ocean fronts at the northeast of the peninsula create south-westerly winds which are strong and constant.
- During summer, the anticyclone centres on the Azores Islands, from where it gets its name, arriving in the form of a cradle in Galicia, creating north-easterly wind. They are usually light winds; however, they can also sometimes blow stronger.
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