Many authors have shown that in China, the contribution due to surface friction to the height tendency of an isobaric surface is of the same order of magnitude as those of the large-scale topographic influences and that under some special weather situations, the non-adiabatic heating is non-negligible to the height tendency even if in short-range forecasting.

In the developing of the heavy rainstorm and southwest vortex in July of 1981, the release of latent heat of precipitation plays the most important rule, the effect of barrier of Tibetan Plateau has an important rule, and the fluxes of surface sensible and latent heat, surface friction and lateral friction in boundary layer have a certain contributions to the development of southwest vortex, intensifing of upward motion, and the heavy rainfall as well.

Based on the original operational limited area model, a new high resolution limited area model was developed and started operational run on May 15, 1996. Besides the increasements of horizontal resolution, the main improvements in the model are: (1) introduction of more reasonable physical processes, such as soil process, the budget of radiation on surface, surface friction and vertical diffusion in PBL;

According to the flow feature, a two dimensional fluid dynamics model of airflow over mountain was set up, from the potential flow theory around cylinder with considering the velocity form of mountain.

The effects of both frictional convergence in the boundary layer and vertical horizontal internal frictions on the topographic standing waves are preliminarily discussed.

The model physics are orography, moisture process, time-dependent vertical stability, land surface heat budget, contrast between land and sea, climatic mean distribution of solar radiation absorbed by the land and sea surface in winter and parameterizations of long-wave radiation.

The present model,including more physical processes,is a six-level primitive equation modelfor Asia area with efficient and accurate numerical techniques for the computations of pressuregradient force and the initial fields in the vicinity of mountains in σ—coordinate.

It lays down a foundation for studying the relations between tire mechanics and contact pressure distribution as well asfriction characteristics of road surface. It also presents an effective way for tire test data processingand vehicle dynamics analysis.

Singular solution of boundary layer equations which can be extended continuously through the point of zero surface friction

The present case is distinguished by the structure of the free interaction region in a small neighborhood of the point of zero surface friction stress.

As a result, an integrodifferential equation describing the behavior of the surface friction stress function is obtained.

The effect of the principal determining parameters of the problem on the flow structure in the shock layer and the surface friction and heat transfer coefficients is analyzed.

Separation takes place along the limiting streamline at the points of which the component of the surface friction (calculated from the boundary-layer equations) that is orthogonal to this streamline has a break.

These include reduced ground friction (ice) and modified gravitation (moon walking).

For small values of ground friction coefficient and under the fulfillment of a certain condition on the function giving the depth of the sea, we prove the existence of a generalized periodic solution.

For example, an totally stable wheeled robot cannot measure the ground friction through a visual sensor.

However, accurate tire/ground friction models are difficult to obtain analytically.

This experimental result again shows that both contact detector and visual sensor are able to display the difference in the ground friction.

Integrating with respect to time the equation for the balance of angular momentum of the atmosphere north of certain latitude (30°N say)we obtainIn the above equation ρ is thedensity; (?), the zonal wind; v, the meridional wind; R, the earth's radius; Ω, the angular speed-of the earth's rotation; dm, the mass element of the atmosphere; dτ, the volume element; ds, the area element on the earth's surface, and dσ, the urea element on the vertical surface over the latitudial circle of 30°N. The first two terms (in...

Integrating with respect to time the equation for the balance of angular momentum of the atmosphere north of certain latitude (30°N say)we obtainIn the above equation ρ is thedensity; (?), the zonal wind; v, the meridional wind; R, the earth's radius; Ω, the angular speed-of the earth's rotation; dm, the mass element of the atmosphere; dτ, the volume element; ds, the area element on the earth's surface, and dσ, the urea element on the vertical surface over the latitudial circle of 30°N. The first two terms (in the parenthesis) On the left side of (2) are evaluated from the mean westerlies in summer and winter given by Mintz. The last two terms on the left and the first two terms on the right side of (2) are evaluated from the mean surface pressure charts of July and January. The transfer of angular momentum across latitude 30°N given by Starr and White is used to evaluate the 3rd. term on the right. Then the value of the last two terms in the parenthesis on the right of (2) is calculated. The result agrees very well with that obtained by other authers.It is further found that: 1. From summer to winter the transfer of angular momentum from low to high latitudes by gross weather systems overcompensates the destruction by the earth's surface. The small residue of these two factors acounts for the main part (about85%)of increase of westerly circulation from summer to winter. The remaining small part of the increase of the westerly circulation may be acounted for by the advection of mass of the atmosphere, which carries the angular momentum due to earth's rotation (difference between the first two terms on the right and the last two terms on the left side of (2)).2. The transfer of angular momentum or the destruction of angular momentum, as well as the intensity of the westerly circulation has annual variation. However this annual variation is not of sine or cosine type, i,θ, the variation from summer to winter is not the opposite of that from winter to. summer. The property of this asymmetry is explained by the irreversible heat addition and subtraction. From winter, to summer heat is added to, and summer to winter heat is subtracted from the atmosphere (N.H.). Since the process of adding and subtracting heat is irreversible, the variation from summer to winter can not be symmetric to that from winter to summer.3. Transfer of angular momentum from easterlies to westerlies occurs mainly in the period of breakdown of zonal circulation (low index), mainly in the belt of longitudes of"extended troughs" (troughs extending from high to low latitudes) and "extended ridges" (ridges extending from low to highlatitudes), and mainly in the high levels of the atmosphere.

In the long-period numerical forcast models, many factors, such as non-adiabatic heating and friction, must be considered. The object of this paper is to study the stability of long wave under the influence of these factors. A two-level quasi-geostrophic model including the effect of non-adiabatic heating, friction and horizontal austausch (1)-(3) is used. The instability criterion is given as (10). In the case of baroclinic atmosphere without these factors the criterion agrees with that of Phillips'(fig. 1)....

In the long-period numerical forcast models, many factors, such as non-adiabatic heating and friction, must be considered. The object of this paper is to study the stability of long wave under the influence of these factors. A two-level quasi-geostrophic model including the effect of non-adiabatic heating, friction and horizontal austausch (1)-(3) is used. The instability criterion is given as (10). In the case of baroclinic atmosphere without these factors the criterion agrees with that of Phillips'(fig. 1). It is found that in barotropic atmosphere the friction and horizontal austausch are purely damping factors. In baroclinic atmosphere it is, however, not so simple. With the parameter A_T=A_v=0.00213 arc~2 day~(-1),k=0.26 day~(-1),ε=1.05 arc~(-2) day~(-1), A_1~2=30.4 arc~(-2), the curves of stability criterion are given in fig. 2. We notice in the figure that for sufficiently short wave or for small wind shear, these parameters are damping factors; but for long waves (m, n<3) the minimum baroclinity for initia'e instability is smaller than that for the case without these factors. Finally, the structure of the unstable wave.is shown in fig. 4a-b. Fig. 4a is without damping factors and the other is with these factors under the same baroclinity. It may be seen that these factors decrease the instability. In the case without damping factors the disturbance starts to damp when the temperature wave and pressure wave are in phase, but in the case with damping factors the disturbance starts to damp when the phase of temperature wave is still left behind the pressure wave (fig. 4c). This is because when the phase of temperature wave is left behind the pressure wave, there is release of potential energy and this energy is used to compensate the frictional loss.

Many authors have shown that in China, the contribution due to surface friction to the height tendency of an isobaric surface is of the same order of magnitude as those of the large-scale topographic influences and that under some special weather situations, the non-adiabatic heating is non-negligible to the height tendency even if in short-range forecasting. By taking into consideration of above mentioned three effects, a two-parameter baroclinic model suitable for numerical weather prediction is derived from...

Many authors have shown that in China, the contribution due to surface friction to the height tendency of an isobaric surface is of the same order of magnitude as those of the large-scale topographic influences and that under some special weather situations, the non-adiabatic heating is non-negligible to the height tendency even if in short-range forecasting. By taking into consideration of above mentioned three effects, a two-parameter baroclinic model suitable for numerical weather prediction is derived from the combination of hydrodynamic and thermodynamic equations. The solutions of the system of prognostic equations are given. Then this paper deals with the truncation errors in the numerical weather prediction when a triangular grid-point system is used. Moreover, an optimum smoothing formulas for the field is developed. Finally, the author gives a brief discussion on the problem concerning the development of the large-scale baroclinic disturbances.