ABSTRACT
This chapter considers different techniques for estimating the vertical motion which are developed. It examines both the cases where data are regularly and irregularly spaced over a horizontal domain. The vertical wind velocity is not an observed variable in meteorology, and its estimation appears as one of the most difficult problems. The vertical velocity is an integral component of the three dimensional structure of the atmospheric motion and is encountered in many diagnostic and prognostic problems. The simplest method for the computation of the vertical motion would be the integration of the mass continuity equation using the large scale horizontal wind observations and accounting for the divergence correction. The sparseness of observations constitutes, however, a serious obstacle in this so-called kinematic method. Moreover, due to uncertainties inherent to wind measurements, large errors are introduced in the calculation of the horizontal divergence and lead to important errors in the estimation of the vertical velocity.
