ON THE PARTITIONING OF THE BAROCLINIC VERTICAL MOTIONS IN A DEVELOPING WAVE CYCLONE.
CALIFORNIA UNIV LOS ANGELES DEPT OF METEOROLOGY
Pagination or Media Count:
The simple quasi-geostrophic or a more general W-equation of a balanced model can be used in a unique manner to partition the vertical velocities. A study of such a partitioning determines the contributions by several baroclinic processes that are somewhat hard to see from a mere visual examination of the pressure and thermal fields on synoptic weather maps. The results of the quasi-geostrophic partitioning show that the thermal advection and its contribution are quite large even at the open wave stage. This is contrary to Petterssens 1956 views that upper vorticity advection initiates the development of an open wave. The results are in agreement with the linear stability analysis of Phillips 1954 and Ogura 1956. The results of the multi-level baroclinic balanced model determines the importance of some of the terms that are absent in the quasi-geostrophic theory and that are rather large during the life history of a wave cyclone. Large magnitudes to the baroclini vertical motions are contributed by a part of the divergence term in the vorticity equation which is neglected in the quasi-geostrophic models. Contributions by the deformation terms of the balanced stream function are also large and contribute significantly to the storm dynamics during its growth. A multi-level diagnostic balance model is demonstrated as a powerful tool for studying three dimensional details of the non-geostrophic behavior of the atmosphere during various stages of a storm development. Author
- Atmospheric Physics