In the studies of turbulence using higher-order turbulence schemes, several terms need to be parameterised. Among those, the pressure-correlation terms have historically been of difficult parameterisation due to several reasons. The most important one has been the difficulty of having adequate measurements of the pressure in the precision of the PBL phenomena (below 10 Pa) at a sufficiently high sampling rate, and without problems of temperature drifting of the sensor. This defficient experimental knowledge results in parameterisations that can be far from reality.

During the CASES-99 field campaign, three microbarometers using the change of the oscillation frequency of a quartz crystal with a temperature compensated output were set up. In order to have enough resolution, they were sampled at 2 Hz. Using the continuous wavelet transform, estimations of the pressure fluxes and correlations with variables out of sonic anemometers have been computed.

In order to check the importance of the pressure-correlation terms, the TKE budget has been computed for several classical regimes of the PBL (convective, shear-driven and stable. This procedure can also help to study if the hypothesis of parameterising them together with the turbulence transport terms is of application. The conclusions will be shown in this presentation.