论文标题
纬度差异旋转对太阳罗斯比波的影响：赤道$β$平面中的临界层，特征函数和动量通量
Effect of latitudinal differential rotation on solar Rossby waves: Critical layers, eigenfunctions, and momentum fluxes in the equatorial $β$ plane
论文作者
论文摘要
在太阳上观察到垂直涡度的逆向传播波在太阳上观察到，分散关系接近经典的部门罗斯比波。观察到的涡度特征函数在纬度上是对称的，在赤道处达到峰值，开关标志接近$ 20^\ circ $ - $ 30^\ circ $，并在较高的纬度下降低。我们搜索一个考虑太阳纬度差异旋转的解释。在赤道$β$平面中，我们研究了抛物线层层剪切流中线性rossby Waves（相位速度$ c <0 $）的传播，$ u = - \ u = - \ overline {u} \ξ^2 <0 $，其中$ \ edimelline {uperline {U} = 244 $ m/s和$ m/s and $ m/s and $ m/s and $ c。在无关紧要的情况下，特征值频谱是真实且连续的，并且速度流函数在$ u = c $的临界纬度上是单数的。我们在问题中添加了涡流粘度，以解释波浪衰减。在粘性情况下，流函数是四阶修改的ORR-Sommerfeld方程的解决方案。特征值是复杂且离散的。对于对应于超晶尺及以上的涡流粘度的合理值（雷诺数$ 100 \ le re \ le 700 $），所有模式都是稳定的。在固定的纵向波数字上，最小阻尼模式是一种对称模式，其真实频率接近经典的Rossby模式，我们称之为R模式。对于$ re \ \ 300 $，本征功能的衰减和实际部分与观测值（与特征功能的虚构部分不同），在模型中具有较大的振幅。结论：每个纵向波伯伯伯伯伯伯伯氏静脉的纵向较大的模型在低纬度上的旋转群体在较低的模型中的旋转群体相互依存，而在较低的旋转中旋转的旋转序列在较低的旋转中的转换率在旋转中的旋转序列偏离了旋转的旋转，该模型在旋转中的旋转序列在旋转中的旋转序列在旋转中的旋转序列偏离了数字。从耗散层向赤道的角动量。
Retrograde-propagating waves of vertical vorticity with longitudinal wavenumbers between 3 and 15 have been observed on the Sun with a dispersion relation close to that of classical sectoral Rossby waves. The observed vorticity eigenfunctions are symmetric in latitude, peak at the equator, switch sign near $20^\circ$-$30^\circ$, and decrease at higher latitudes. We search for an explanation that takes into account solar latitudinal differential rotation. In the equatorial $β$ plane, we study the propagation of linear Rossby waves (phase speed $c <0$) in a parabolic zonal shear flow, $U = - \overline{U}\ ξ^2<0$, where $\overline{U} = 244$ m/s and $ξ$ is the sine of latitude. In the inviscid case, the eigenvalue spectrum is real and continuous and the velocity stream functions are singular at the critical latitudes where $U = c$. We add eddy viscosity in the problem to account for wave attenuation. In the viscous case, the stream functions are solution of a fourth-order modified Orr-Sommerfeld equation. Eigenvalues are complex and discrete. For reasonable values of the eddy viscosity corresponding to supergranular scales and above (Reynolds number $100 \le Re \le 700$), all modes are stable. At fixed longitudinal wavenumber, the least damped mode is a symmetric mode with a real frequency close to that of the classical Rossby mode, which we call the R mode. For $Re \approx 300$, the attenuation and the real part of the eigenfunction is in qualitative agreement with the observations (unlike the imaginary part of the eigenfunction, which has a larger amplitude in the model. Conclusion: Each longitudinal wavenumber is associated with a latitudinally symmetric R mode trapped at low latitudes by solar differential rotation. In the viscous model, R modes transport significant angular momentum from the dissipation layers towards the equator.
