青藏高原动力和热力作用对热带大气环流影响的数值研究

Numerical Study of the Effects of Dynamic and Thermodynamic of QinghaiXizang Plateau on Tropical Atmospheric Circulation in Summer

应用在CCM3气候模式基础上发展的一个CCM3(R15L9)长期预报模式 ,进一步研究了青藏高原热力和动力作用对夏季热带地区大气环流的影响。结果表明 :在 6月初夏季节 ,青藏高原动力和热力作用在 30°N和 30°S一带有明显的增温效果 ,有利于北半球副热带西风减弱北移、热带高层东风增强北进、南半球西风带北压和赤道中低层西风形成和加强。加速了季节转换过程 ,有利于增强越赤道气流和南北半球的大气交换作用 ,还有利于在南海、菲律宾以东海面上热带气旋的形成和发展 。

By employing the CCM3(R15L9) long range spectral model developed on the basis of CCM3 climate model, the seasonal simulations have been carried out to investigate the dynamic and thermodynamic effects of QinghaiXizang Plateau on the tropical atmosphere circulation in June, 1996. The results show that the dynamic and thermodynamic effects of the Plateau in early summer are obviously favorable for increasing the air mass temperature over the belts near 30°N and 30°S, and contribute to the northward shift of the Northern Hemisphere subtropical westerly jet, the enhanced tropical upperlayer easterlies and help to enhance the equatorial western flow at lower and middlelayers. All these roles are helpful of accelerating of the season transition. The Plateau′s influences contribute to the genesis and enhancement of the crossequatorial air flow, and play profound impacts on the mass exchanging between the Northern and Southern Hemisphere. Fourthly, the effects of the Plateau are beneficial to the development of the easterly wave motion over tropical Pacific lying east of 140°E, which also suggests that its effects help to reinforce tropical cyclones over South China Sea and about 2 000 km to east of Philippine.