Trends and Variations of Mean Temperature in the Lower Troposphere

Abstract

Deviations of the 1000–500 mb thickness from the 1949–76 mean (the period of record) and from the 1965–76 mean (a period of apparent warning in the lower troposphere) are presented for the Northern Hemisphere (25–85°N), the arctic (70–85°N), and the low-latitude belt (25–40°N). Results are compared with those obtained by other investigators from surface and upper air data. A dramatic drop in the mean temperature of the lower troposphere to the lowest point of the record occurred between January 1975 and August 1976. This cooling followed a slow warming trend between 1965 and 1975 which was greater at low latitudes than in the arctic.