Rotational and Divergent Geopotential Components
Rotational and Divergent Geopotential Components
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DOI：
10.1175/1520-0469(1988)045
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发表时间：
1988-10
影响因子：
3.1
通讯作者：
K. Trenberth;Shyh-C. Chen
中科院分区：
文献类型：
--
作者：
K. Trenberth;Shyh-C. Chen
传统的气象学方法是将速度场分为旋转分量和辐散分量，而不将位势场分为旋转分量和辐散分量。然而，任何平衡条件，如地转关系或线性平衡方程，都是一个诊断关系，它表明不仅可以从位势场计算出平衡的速度场，而且可以从速度场导出位势。如果采用后一种方法，那么观测到的和计算出的位势之差就是我们所说的发散位势，或者在某些情况下，非地转位势。事实上，对于任何平衡方程组，必须以这种方式划分地球势，以便导出等效的动量方程组。给出了与线性平衡方程组等价的动量方程。通过对线性平衡方程的积分，给出了旋转风分量与涡旋梯度之间的诊断关系。
Abstract It has been traditional in meteorology to divide the velocity field up into rotational and divergent components, but not the geopotential field. Yet any balance condition, such as the geostrophic relation or linear balance equation, is a diagnostic relation which states that not only can the balanced velocity field be computed from the geopotential field, but also that the geopotential can be derived from the velocity field. If the latter approach is adopted, then the difference between the observed and computed geopotential is the quantity we refer to as the divergent, or in some cases, ageostrophic, geopotential. In fact, for any balance set of equations, it is essential to partition the geopotential in such a way in order to derive an equivalent set of momentum equations. The momentum equations equivalent to the linear balance set of equations are given. The linear balance equation is integrated to give a diagnostic relation between the rotational wind components and the gradient of the rotati...