A 15-year climatology of Northern Hemisphere 500 mb closed cylone and anticyclone centers

Abstract

The occurrence of closed cyclone centers is maximized north of and within the main belt of westerlies extending from northeast Asia to the Gulf of Alaska near 50°N, and extending from eastern Canada and the extreme northeast United States to southeast of Greenland and west of the United Kingdom. Their occurrence is also maximized south of the main belt of westerlies in a band extending from the east-central Atlantic Ocean across southern Europe to the Caspian Sea and central Asia. The occurrence of closed anticyclone centers is maximized over the subtropical oceans in all seasons and over the subtropical continents during the summer. These centers show a tendency to be displaced substantially northward along the west coasts of both North America and Europe. -from Authors