On The Theoretical Of The Hydrostatic Adjustment In The Compressible Atmosphere

To study the theoretical hydrostatic adjustment of a compressible dry atmosphere model,at the beginning of this thesis,the governing equations and the corresponding perturbation forms are derived,the energy budget equations are established.Based on these equations,the physical mechanisms of hydrostatic adjustment are revealed from the perspective of the wave response,the movement characteristics of parcel,and the energy transportation,respectively,any atmosphere variable is divided into a static one and a non-static one.And then,the density function of wave energy is defined,by analyzing its evolution equation,the wave-flow interaction during the process of adjustment is examined,as well as the effects of initial perturbation on the hydrostatic adjustment with the help of the ideal numerical experiment.Finally,the preferred vertical variable configuration schemes in the non-static compressible atmospheric numerical prediction model are presented.The acoustic wave and the acoustic-gravity wave,which play the quite different roles during the hydrostatic adjustment,are stimulated immediately by the non-static perturbation energy when the hydrostatic balance state is destroyed.In the static atmosphere model,the perturbation energy is dispersed by the acoustic wave and acoustic-gravity wave to the entire space to achieve the reconstruction of the hydrostatic balance.While,in the non-static atmosphere model,there is an energy transportation between the perturbation state and the basic state,which induced by the basic flow and its vertical shear,with the decay-type wave structure,the wave energy is decayed over time because of the energy transported form the basic state to the perturbation state,which is helpful to the hydrostatic adjustment fulfillment;on the contrary,with the develop-type wave structure,the wave energy is developed over time because of the opposite direction of the energy transportation compare to the decay-type mode,which led to the failure of the hydrostatic adjustment.The track of parcel presents a spiral surface in the three-dimensional hydrostatic adjustment process,which is the collaborative result of the acoustic wave and the acoustic-gravity wave.The basic flow and its vertical shear are the important factors when studying the motion characteristic of perturbated parcel;the function of acoustic wave is driving the parcel oscillation from vertically to horizontally with the decreased perturbation scale,while,the acoustic-gravity wave drived the parcel in the contrary way;these two kinds of waves play an inhibitory role in the oscillation process,but the acoustic wave dominated in the initial stage of hydrostatic adjustment.The non-static perturbation energy is mutual converted between the forms of the kinetic energy,the available potential energy,the available elastic potential energy,and the basic energy,during the hydrostatic adjustment,where the available elastic potential energy acts as the ‘center station role’ in the energy transportation,the conversion between the vertical branch of perturbation kinetic energy and the available potential energy can be appointed as the indicator to measure the extent to which the balance is destroyed.Moreover,the mutual direction of hydrostatic adjustment between the horizontal wind field,the buoyancy field,and the pressure field,are comprehensively affected by many factors,such as the initial perturbation property,the wave characteristic,the scale of perturbation,the structure of basic flow,and the stability parameter of atmospheric.In the western jet model of mesoscale,the direction is adjusted from the pressure field to the buoyancy field,which is corresponding to the initial perturbation of velocity or density;while,the direction is changed oppositely,with the initial pressure perturbation.Otherwise,in the mesoscale perturbation,the initially pressure-horizontal wind direction is turned to a mutual adjustment type along with the scale decreased.The hydrostatic adjustment is an important composition of the heat and the momentum delivery,and their major mechanisms are the ridge line slopping of the waves and the vertical shear of the horizontal basic flow;for the north-south transmission of westerly perturbation momentum,the effects of two kinds of waves are the same,but for the vertical transmission of horizontal perturbation momentum,the effects of acoustic wave and acoustic-gravity waves are opposite.While,the transmission of heat flux are affected by the wave frequency,the location of wave in the basic flow,and the stratification parameters of atmosphere,respectively.And the vertical heat flux is conserved in a wave period time.Based on the evaluation criteria of analytic dispersion equation and group velocity equation,at the same time,the hydrostatic adjustment and the adjustment of baroclinic atmosphere are comprehensively considered,the vertical variable schemes preferentially adopt the CP grid,the L_N grid and the L grid in the non-hydrostatic fully compressible deep atmospheric numerical prediction model.