Large-Scale Disturbances in the Summertime Stratosphere

Abstract

High-level balloon data from the region of western Europe through North America to eastern Asia were used to investigate disturbances in the summertime stratosphere from 27–36 km. Systematic diurnal variations were found, with amplitudes up to 2 m sec⁻¹, but the patterns were more complex than would be expected from simple tidal theory. Traveling planetary waves were also found at these altitudes, propagating westward at 30° of longitude per day. The waves were detected as periodic oscillations in the u component, with amplitudes up to 4 m sec⁻¹, extending from 25–45N, and from 25–45 km in the vertical. A solution to the barotropic vorticity equation was found which possesses many of the observed features when applied to 10 mb (31 km) data. While it is suspected that both the diurnal wind patterns and the traveling waves are forced by tropospheric disturbances, the causes of neither could be determined.