積雲対流の大規模組織化の数値実験(対流(3),一般講演)

概要

論文の詳細を見る
Space-time structure of cloud convection in the earth's tropical atmosphere is investigated with by long-term integrations of a large-domain two-dimensional numerical model that can explicitly resolve cumulus convection. Several kinds of structure develop spontaneously depending on the model parameters such as the vertical distributions of body cooling in the model atmosphere and the specification of heat flux from the underlying ocean. In the experiments forced by a "top heavy" cooling, a distinct transition is observed in the simulated large-scale space-time structure of cloud convection: a standing oscillation type pattern with the wavelength of 〜3,000km that establishes in about 10 days from the start of the experiment is taken over by a stationary pattern with 〜30,000km wavelength. Heat budget analysis shows that, associated with the transition, the altitude of the heating by the condensation of water vapor in the later stage becomes lower and the vertical heat transport becomes larger, suggesting an increase of thermodynamic efficiency.
2008-09-04