Stratospheric temperatures during solar cycle 20

Summertime rocketsonde temperature data for 1965–1977 at seven sites, 8°S‐64°N, were adjusted to reduce previously uncorrected instrumental errors. The data were then carefully processed to yield yearly average temperature departures from the average temperatures for 1965–1977. At two levels, 35 and 50 km, the yearly departures as well as 3‐year moving averages (with 1‐2‐1 weighting) were compared to the mean annual sunspot number, both for individual stations and for the combined station data. The smoothed temperature departures for the combined data show a correlation of +0.89 with sunspot numbers at both altitudes but with greater temperature range (4.5°C) at 35 km. Except for two special circumstances, correlations at individual stations (smoothed data) range from +0.72 to +0.94; the corresponding amount of temperature change from near‐solar maximum (1969) to near‐solar minimum (1975) varies among the stations from −3°C to −6°C. The observed temperature variations during solar cycle 20 are well within recent model calculations that are based on observed fluctuations in solar ultraviolet radiation.