The Cellular Solution of the Dynamical Equations and the Actual Perturbation of the Westerlies up to 16 km at Valentia

Abstract

The cellular solution of the linearized hydrodynamical equations requires the existence of nodal surfaces for the perturbation of air density, pressure and velocity components. When a constant, which appears in the formulae giving the heights of the nodal surfaces, is determined from the observed value of one of them, namely, the first nodal surface of the vertical velocity, all the other heights of nodal surfaces agree within reasonable limits with the heights determined from actual observations by several investigators using very different methods. More than 400 upper wind ascents reaching at least 16 km made by radio wind or radar methods at Valentia Observatory, have been classified according to the sign of the change of pressure at 8 km during the 12 hours prior to the ascent, and average values of the meridional and zonal components of the wind have been computed. The difference at each level between the corresponding average components of the wind when the pressure has increased and when the pressure has decreased gives a good approximation to double the value of the horizontal perturbation of the Westerlies. Applied to this case, the cellular solution requires that the zonal component of the perturbation so determined should be zero at all levels while the meridional component should have nodal surfaces at 4 and 12 km. The observations show that the zonal component is the one having nodal surfaces at the required levels while the meridional component has a maximum value at about 9 km. Taking into account that the equations refer to a single-layer atmosphere and neglect the meridional gradient of temperature, the disagreement between observation and theory appears to be less significant than the confirmation of the existence of nodal surfaces which cannot be explained by the generally accepted exponential solution of the dynamical equations.