Estimate of the Global Change in Temperature,Surface to 100 mb, Between 1958 and 1975

Abstract

The global variation in temperature, during the period 1958–75 is investigated using a sample of 63 radiosonde stations. The surface temperature as well as the mean temperature in 850–300 mb and 300–100 mb layers is examined, the latter based on thickness analysis. Between 1958 and 1965 there was a significant cooling averaging about 0.3°C over much of the globe, but since 1965 the temperature variations have been small. During the past few years there has been a slight warming in most latitudes. The meridional temperature gradient between the tropics and temperate latitudes has continuously increased, but since 1965 the temperature gradient between temperate and polar latitudes has decreased, with an especially large surface warming indicated for Antarctica. In the tropical troposphere, a temperature oscillation of about 3-year period and 0.3°C amplitude has been dominant since 1965. The eruption of Mt. Agung in 1963 may have decreased the surface temperature by as much as 0.2°C in the tropics, 0.4°C in the south extratropics and 0.6°C in the north extratropics. In the south extmtropics there was also a 0.7°C warming and cooling in the 300–100 mb and 850–300 mb layers, respectively, in the year of the eruption. Also shown is the variation with longitude of the temperature changes and the tendency for increased spatial variability of temperature.