What is an anticyclone?
An anticyclone is an atmospheric zone of high pressure often associated with dry, cloudless, sunny skies. It is the movement of air masses that favors its appearance. Cold air masses increase ground pressure and prevent cloud formation. It's a slow, vertical activity with a dissipative effect. There are two types of anticyclone: thermal and dynamic. The former are cold-core, while the latter are warm-core. Constantly moving and evolving with the seasons, anticyclones are simply a shield against precipitation. For the record, it was French meteorologists in the last century who pinpointed the location of this phenomenon. This discovery was partly responsible for the creation of the research station on the island of Flores.
What is the difference with depression?
Conversely, a depression is an area of low pressure, where the air is warm and light. Air pressure on the ground is low, creating a suction effect. The air coming from the ground is laden with moisture and cold, favoring the creation of clouds, wind and rain. The result is bad weather. It can even become a cyclone.
The North Atlantic High
The North Atlantic High is also known as the Bermuda High in the USA and the Azores High in Europe and Africa. Also known as the subtropical ridge, it directs and "controls" the winds, more specifically the trade winds from tropical regions. But not only that, as westerly winds, initially very dry, moisten over the Atlantic Ocean and converge in the same direction. In the Northern Hemisphere, winds flow in a clockwise direction. This leads to fine weather, as the air warms up and becomes relatively dry. The Bermuda-Azores anticyclone system shifts with the seasons: it is centered on the Bermuda triangle in summer and autumn, then on the Azores in winter and spring.
The Gulf Stream, cause or effect of the anticyclone?
The Gulf Stream is a warm ocean current that originates between Florida and the Bahamas and flows into the Atlantic Ocean. It passes through the Azores, but is there a link with the famous anticyclone? It is in fact the wind associated with the anticyclone phenomenon that allows the creation of this current. Manifestations that are created in the air are also created under the mirrored ocean. There are other phenomena of the same kind all over the world. They are in fact agents of heat transport.
Concretely in Western Europe
What does this mean? If the Azores High is not very active, it lets the lows through and the weather in Europe is grey and cold. On the contrary, if it blocks the lows, the weather is dry and calm. In fact, it acts as a sort of anti-frost shield. In the Azores, people have learned to live with the vagaries of the weather. Azoreans are both optimists and fatalists. Subjected to the variations of the Atlantic climate, it's not uncommon to experience the four seasons in a single day!
