The Vertical Temperature Distribution and the Layer of Minimum Temperature

Abstract

Seven years of temperature observations from Cape Canaveral, Florida, are used for a detailed examination of the vertical temperature structure. In the troposphere, temperature variations increase with time; in the stratosphere 12-hour temperature changes are greatest and 24-hour changes are least, showing the diurnal temperature control. In the troposphere, temperature variations are greatest in winter, least in summer; the reverse is true in the stratosphere. The smallest annual median temperature range, 3.6C, occurs at 13 km altitude. Stratospheric temperatures over Cape Canaveral are warmest in early spring, coinciding with the maximum ozone concentration of early spring, with only 2?3 months elapsing between the warmest and coldest temperatures of the year. Cape Canaveral summer temperatures compare closely to the mean summer temperatures of other tropical maritime areas, as shown by earlier studies. Three years of temperature data, at 23 stations from Eureka to Amundsen-Scott, are used to establish a global profile of summer and winter tropopause heights. In the equatorial belt, temperatures in the lower stratosphere are coldest in January and warmest in July, both north and south of the equator. The temperature distribution indicates that the tropopause is generally higher in winter than in summer in all latitudes. The lowering of the summer tropopause occurs with an increase of water vapor in the lower troposphere. From Buffalo to Albrook, somewhere in the 12?18 km region, a temperature belt is found that is warmer than the annual average at that attitude in winter, and colder than the annual average in summer. Another region with seasonal temperature reversals is indicated above 32 km.