At the Umeå Division the propagation of the infra sound in the atmosphere is studied. Due to special problems with detection of infra sound from distant sources, like a low signal-to-noise ratio and a strong influence of the atmospheric structures on the propagation of infra sound, a major part of the work at IRF-Um was concentrated on development of new methods for signal processing and data analysis.

Recent work includes:

Propagation of infrasonic waves

• Studies of the fine structure of the infrasonic signals generated during supersonic flights of Concorde.
  
• Studies of the long term variations (since 1978) of the wind system above the Northern Atlantic using the infrasonic signals generated by Concorde.
  
• Infrasonic detection of meteor impacts.
• Infrasonic detection of high altitude discharges - sprites.

Space Science Data Analysis Tools

• Applications of neural networks for intelligent processing of large quantities of data; automatic categorization and construction of statistical models.
  
• Applications of the causal modeling to different kinds of spectral data.
  
• Applications of wavlets to signal and image processing.

Publications at IRF-Um

Staff at IRF-Um