Thermistor observations taken at Jämtön, Sweden and at other IRF (Swedish Institute of Space Physics) stations exhibit two basic types of temperature oscillations. One type is observed in the summer and forms in association with severe convective thunderstorms. This is the subject of this paper. The other type forms primarily during stable surface boundary layer conditions in winter following the arrival of infrasonic pressure waves from the Concorde supersonic transport (Liszka, 1974, Liszka and Waldemark, 1995). The observed summer temperature oscillations as recorded on vertical masts of thermistors (at heights of 0, 1, 2, 3, 4, and at 5 m) are very large in amplitude (about 5 - 10 K).and appear coupled in some way to the presence of severe convective thunderstorms. In order to predict future conditions, we have used a one-dimensional boundary layer model (BLMARC), properly initialized, to examine the surface and planetary boundary layer behavior during this type of event. The model predicts a bursting type event (ReVelle, 1993) about 1 hour after the model initialization, in very good agreement with the onset of the observed temperature oscillations. It also predicts an amplitude envelope for the mean temperature field that encompasses the full range of the temperature oscillation amplitudes that are found in the thermistor data. Possible causes of this behavior are examined.
IRF Scientific Report 256
1999.