Dynamic Interactions between the Troposphere and Stratosphere.

• Main Author: Koermer,James Paul
• Other Authors: AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
• Format: Text
• Language: English
• Published: 1980
• Subjects: Meteorology; *TROPOSPHERE; *STRATOSPHERE; INTERACTIONS; THESES; VERTICAL ORIENTATION; HEATING; WAVES; Stratospheric warming; Planetary waves; polar night
• Online Access: http://www.dtic.mil/docs/citations/ADA092420; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA092420

A primitive equation spectral model using spherical harmonics is formulated to study interactions between the troposphere and stratosphere in association with sudden stratospheric warmings. In order to follow vertical wave propagation so important to this process, the model consists of 31 levels with 5 in the troposphere and the other 26 in the stratosphere and mesosphere. Using sigma coordinates for the former and log-pressure coordinates for the latter, separate equations for each system are combined to form a single matrix governing equations. The gradual introduction of planetry scale topography to an initially balanced state representative of observed mean winter conditions in the Northern Hemisphere is used to force changes in the initial field during 40 day time integrations. Utilizing the same initial tropospheric conditions, three cases were run. The first case started with a weak polar night jet in the stratosphere and mesosphere. The second case had a much stronger polar vortex. For the third case, a lid was placed on the troposphere and no interaction was allowed with the atmosphere at higher levels. Results of these integrations indicate that realistic stratospheric warmings can be simulated by simple orographic forcing.