  The data of simultaneous measurements of the surface displacement produced by
propagating planar waves in experimental flume and of the dynamic pressure
beneath the waves are compared with the theoretical predictions based on
different approximations for modulated potential gravity waves. Regular and
irregular wave sequences in intermediate depths are considered. The efficiency
of different models for reconstruction the pressure field from the known
surface displacement time series (the direct problem) is investigated. A new
two-component theory for weakly modulated weakly nonlinear waves is proposed
showing the best performance among all applied models. Peculiarities of the
vertical mode of the pressure second harmonic are discussed.
