Coherent pressure disturbances during CASES-99

Coherent, i.e. non-turbulent, atmospheric pressure perturbations observed with a ground-based array of 7 microbarographs and a vertical array of 3 microbarographs on a 55 m high tower are analized for 11 intensive observing periods (IOP) during the CASES-99 field program. The data are examined using wavelet analysis, beam steering and spectral analysis. The quality and quantity of perturbation activity are correlated with nighttime static stability and wind speed. The majority of pressure perturbations are due to gravity waves. The vertical variations of the wave characteristics are examined using the vertical array of microbarographs.