The Icelandic Low is a semi-permanent centre of low atmospheric pressure found between Iceland and southern Greenland and extending in the Northern Hemisphere winter into the Barents Sea. In summer it weakens and splits into two centres, one near Davis Strait and the other west of Iceland. It is a principal centre of action in the atmosphere circulation of the Northern Hemisphere, associated with frequent cyclone activity. It forms one pole of the North Atlantic oscillation, the other being the Azores High.