Speculative mean monthly temperatures in the Arctic (75°N) stratosphere, 25 to 55 kilometers

Radiosonde data for latitude 60°N have been combined with available meteorological rocket wind and temperature observations at Fort Churchill, Canada (59°N), and Fort Greely, Alaska (64°N), in order to estimate the annual stratospheric temperature regimes between 25 and 55 km at 75°N. Using the thermal wind relationship, mean monthly temperatures were extrapolated northward by 5-km altitude intervals from 60 to 75°N. Resulting temperature patterns at 75°N compare favorably with observed values at radiosonde altitudes. Above 30 km, however, temperature regimes must be considered speculative, since, at 75°N, observations at these heights are almost nonexistent. The annual temperature at lower latitudes increases in amplitude with distance from the equator. In this study harmonic analyses reveal that this pattern continues at all levels into the polar regions. The annual range of mean monthly temperatures, based on estimated values for 75°N and observed values at 60 and 30°N, also increases from 30 to 75°N. The height at which the earliest maximum temperature occurs in the annual cycle lowers toward the pole, probably reflecting the height of the effective top of the stratospheric ozone layer between 30 and 75°N.