涡度拟能的选择性衰变及波的选择

Selective decay of enstrophy and the exciatation of waves

研究β平面上2层的准地转流,通过变分计算得出在给定能量、动量以及环量的约束条件下最小的拟能解.此最小解的形式依赖于所考虑区域纬向长度与径向长度的比例.当纬向长度大于径向长度的某一倍数时,除一种特殊情形外,最小解是Rossby波;反之,最小解的形式取决于能量与动量平方的比值.

For the two-layer quasi-geostrophic flow on β plane, there is a minimum enstrophy if the energy, momentum and circulation are specified. This minimum enstrophy flow is obtained by variational calculation. The form of the minimum enstrophy solutionrelies on the aspect ratio of the channel. If the zonal length of the channel is substantially greater than its meridional width, the solution is always a Rossby wave except a special case. Otherwise, if this inequality is reversed, the form of the solution is decided by the ratio of the energy to the square of momentum.