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A parametrically excited higher-order nonlinear Schr dinger (NLS) equation is derived to describe the interaction of a ,slowly moving planetary-scale envelope Rossby soliton for zonal wavenumber-two with a wavenumber-two topography under the LG-type dipole near-resonant condition. The numerical solution of this equation is made. It is found that in a weak background westerly wind satisfying the LG-type dipole near-resonance condition, when an incipient envelope Rossby soliton is located in the topographic trough and propagates slowly, it can be amplified through the near-resonant forcing of wavenumber-two topography and can exhibit an oscillation.However, this soliton can break up after a long time and excite a train of small amplitude waves that propagate westward. In addition, it is observed that in the soliton-topography interaction the topographically near-resonantly forced planetary-scale soliton has a slowly westward propagation, but a slowly eastward propagation after a certain time. The instantaneous total streamfunction fields of the topographically forced planetary-scale soliton are found to bear remarkable resemblance to the initiation, maintenance and decay of observed omega-type blocking high and dipole blocking. The soliton perturbation theory is used to examine the role of a wavenumber-two topography in near-resonantly forcing omega-type blocking high and dipole blocking. It can be shown that in the amplifying process of forced planetary-scale soliton, due to the inclusion of the higher order terms its group velocity gradually tends to be equal to its phase velocity so that the block envelope and carrier wave can be phase-locked at a certain time.This shows that the initiation of blocking is a transfer of amplified envelope soliton system from dispersion to nondispersion. However, there exists a reverse process during the decay of blocking. It appears that in the higher latitude regions, the planetary-scale envelope soliton-topography interaction could be regarded as a possible mechanism of the establishment of blocking. 相似文献
43.
Roman Teisseyre 《Acta Geophysica》2008,56(2):259-269
We present a new approach to the continuum theories: for solids, our version includes the asymmetric stresses, symmetric strains
and antisymmetric rotations, while for fluids we take the similar assumptions but related to the respective time rates of
these fields.
We consider the constitutive relations and the balance laws: those related to the antisymmetric stresses are equivalent and
substitute the required relations for the angular moment; a similar approach with rates of these fields is applied for fluids.
The stress-dislocation relations are derived and the role of rotation motions in the fracture processes in solids is studied.
A new theory of the extreme motion phenomena in fluids is developed. 相似文献
44.
G.C. Das 《Planetary and Space Science》2004,52(7):581-586
It has been shown that the Korteweg-de Vries equation, derived in inhomogeneous plasma, finds difficulty in obtaining the complete soliton solution and its propagation in plasma and thus fails to exhibit the actual nature of plasma acoustic-wave. The key here lies in the use of an approach, known as sine-Gordon method, which describes successfully soliton propagation along with its precursor. The study shows that the soliton, due to the interaction of negative ions, collapses expecting a source of soliton radiation. Moreover, inhomogeneity, along with weak ionization, effects the precursor to grow faster by generating the energy from its main soliton. The results are interesting in the light of having a parallel observation on radiation, and the formation of dip and hump solitons as similar to those observations made by the scientific satellites. 相似文献
45.
1. IntroductionIn the mid--high latitudes, l' blocking flow" is an importaht part of the low--frequency variability of the atmospheric circulation. Owing to its longevity and large amplitude, a blocking flow configuration can usually cause prolonged anomalous weather situations over certain extratropical regions. Therefore, it has been a primary interest of many synoptic anddynamical meteorologists. In the past decades, the interaction of planetary waves with migratory, synoptic--scale waves h… 相似文献