Analyses of Temperature Variations in the Middle Atmosphere on Pressure vs. Altitude Surfaces

Model studies of temperature variations in the middle atmosphere indicate significant differences in the amplitude of periodic terms, depending on whether the analyses are conducted on pressure or altitude surfaces. It has also ben predicted that the trend terms due to the radiative effects of the increasing ‘greenhouse gases' will occur at different rates on those two surfaces, Analyses to verify those differences have been conducted using zonal-average time series of 13 years of HALOE temperature data over a range of latitudes and at levels from 5 hPa to just above the 0.01 hPa level (or about 36 km to 80 km). Clear differences have been found at some levels and latitudes for the amplitudes of the seasonal and the 11-yr solar cycle terms, as well as for the long-term trend. The findings are generally consistent with predictions. The findings also help to explain the differing results that have been reported in the literature by various groups that have been obtaining long-term measurements of temperature in the middle atmosphere.