陆面过程对大气环流多平衡态的影响

The multi-equilibrium theory of the atmospheric circulation has important theoretical implication in explaining the formation and evolution of the blocking high and the seasonal catastrophe of the atmospheric circulation. Existing theoretical researches focus more on the internal nonlinear physical mechanisms despite the understandings are still imperfect. However, there are little works to investigate how the underlying surface processes influence the multi-equilibrium of the atmospheric circulation. Systematic and in-depth analyses are needed to understand the mechanisms better. This project will couple the thermodynamic equation which considers the radiation transmission process with the large scale vortex equation to form a generalized quasi-geostrophic potential vorticity equation which will be simplified according to different situations. Analytical or semi-analytical or numerical solution would be obtained to study the multi-equilibrium characteristics. Then the impact of the underlying surface (vegetation, desert and so on) processes on the atmospheric circulation could be analyzed theoretically to investigate how and what extent the underlying surface impacts the multi-equilibrium states in atmospheric circulation. The relevant work would be beneficial to the theoretical understanding of the multi-equilibrium phenomena in the atmospheric circulation and it could also give certain theoretical support on the influence of human activity on climate system. Therefore the project would be helpful in both the scientific endeavor and practical significance.

大气环流的多平衡态在解释阻塞高压的形成与演化、大气环流的季节突变等方面有着重要的理论意义。然而目前大气环流多平衡态的研究主要是从大气内部的非线性物理机制入手，尽管对非线性物理机制的理解还不甚完善，另一方面，有关下垫面物理过程对大气环流多平衡态影响的研究也还较为匮乏，有必要针对这一问题开展系统、深入的研究。本项目建立一个考虑辐射能传输过程的准地转涡度方程，引入不同下垫面覆盖（植被、荒漠等）的能量平衡关系作为准地转位势涡度方程的下边界条件，根据不同问题简化方程，解析或半解析或数值求解方程，从理论上分析下垫面属性及分布对大气环流多平衡态的影响，阐述其影响大气环流多平衡态特征的物理机理。相关工作的开展，将有助于深化对大气环流多平衡态的理论认识，并为人类活动影响气候变化提供一定程度的理论支撑，具有重要的科学意义。

建立考虑辐射能传输过程的准地转位势涡度方程，并引入不同下垫面覆盖（植被、荒漠等）的能量平衡关系作为准地转位势涡度方程的下边界条件，研究陆面过程对大气环流多平衡态的影响。将推导所得的非线性准地转位势涡度方程进行最大简化并从理论上研究其多平衡态特征，计算结果指出，涡度方程的最终平衡态均是空间一波结构，但是在位相体现出随机性，由此揭示了涡度方程长期行文的规律性特征。气候系统的长期行为是不可预测的，但是在其长期演变中会受到各种守恒性条件的制约，因此其长期平衡态也很可能会存在一定的规律性特点。这一研究为深入理解长期气候行为提供了一定的理论指导。将涡度方程适当简化，解析下垫面能量平衡对大气环流的影响。这一研究明晰大气环流对温度分布的响应，并可进一步探讨二者的耦合关系，为深入理解陆气相会作用提供理论帮助。