The Three-dimensional Expansion Of Global Atmospheric Circumfluence And Characteristic Analyze Of Atmospheric Vertical Motion

In the point of the global view, the global atmospheric circumfluence can be considered as the sum of the Walker circumfluence, Hadley circumfluence and Rossby circumfluence. This dissertation has developed the definitions of three-dimensional Walker, Hadley and Rossby circumfluence, founded a mathematical model of three-dimensional velocity field expansion, and proved its existence and uniqueness. This work also has addressed a numerical method which has no truncation error in the discrete three-dimensional grid points. The mathematical theory and numerical computation have indicated that the velocity field is equivalent to the three-dimensional circumfluence expansion. Moreover, the expansion process of velocity field is convenient for the study of the three-dimensional atmospheric circumfluence motion features for the low latitude equator zones and even the global regions. The main conclusions are the following.(1) The three-dimensional Walker, Hadley and Rossby circumfluence definition are developed based on the. extension of the vector potential presentation for the velocity field from two-dimensional to three-dimensional space. The partial differential equations for the three-dimensional circumfluence functions are developed in the atmospheric pressure coordinate and its existence and uniqueness are proved. In another word, the expansion of the velocity field in the component of the three-dimensional circumfluence functions is existed and unique.(2) A simple mathematical model for the expansion of the three-dimensional circumfluence is addressed in the atmospheric pressure coordinate and its existence and uniqueness are proved. Also a numerical method in the form of the Fourier series is developed, which has no truncation error at the discrete grid points. The major virtue of this model is that all the components of the variables are the expansion of the Fourier series. By this major virtue, a series truncation numerical method which can preserve the major characteristics of the variables components is developed. The series truncation method is convenient for the analysis of the atmospheric motion's intrinsic features.(3) A numerical method for the elimination of the observation error for the horizontal velocity field is founded according to the non-divergence of the velocity field in the atmospheric pressure coordinate. The numerical results reveal that the major characteristics of the horizontal velocity field are preserved.(4) The velocity fields calculated by the three-dimensional circumfluence functions has been compared with the NCEP ones, which indicated that the horizontal velocity field in the presentation of the three-dimensional circumfluence functions is exactly same with the NCEP horizontal velocity field. The NCEP numerical method, in the computation of the vertical velocity field, has truncation error at the discrete grid points. Though the Fourier series numerical method developed by this dissertation has truncation error at the discrete grid points, it has some limitation about the mathematical models. The computation reveals that the numerical results adopting the Fourier series numerical method accords with the numerical results adopting the NCEP method in some major features, which means that the numerical results adopting the Fourier series numerical method reflects the main features of the vertical atmosphere motion. The further study variance analysis denoted that they are not the same clearly, especially in lands.(5) This work analyses the characteristics of the equator low latitude zones vertical motion. The result reveals that the vertical velocity of Walker circumfluence can reflect the main circumfluence circle of the Walker circumfluence which has the rising airflow in the west equator Pacific Ocean and sinking airflow in the east equator Pacific Ocean and the main circumfluence circle of the anti-Walker circumfluence which has the rising airflow in the west equator Pacific Ocean and sinking airflow in the west equator Indian Ocean. The vertical velocity of Hadley circumfluence also reflects the features that the airflow rises in the equator low latitude regions and sinks in the middle latitude regions.(6) This work analyses the vertical motion in the Tibetan Plateau by utilizing the vertical velocity and its components. The results indicate that the Walker and Hadley circumfluence together give rise to the annual variety characteristics which has rising airflow in the middle, east and sinking airflow in the west and south Tibetan Plateauand the seasonal variety features which has sinking airflow of the middle and south Tibetan Plateau in winter and strong rising airflow of the most Tibetan Plateau areas in summer.(7) This work also analyses the short-term structure characteristics of the subtropical high by utilizing the vertical velocity and its components during July of 1998. The results reveal that the vertical velocity and its components can .interpret the process of the transmeridional fracture of subtropical high during the MeiYu period in the middle and lower reaches of the Yangtse River in July of 1998 and the phase sinking and rising airflow in the subtropical high. It also concludes that the cause of the transmeridional fracture is due to the Walker circumfluence.In sum, the three-dimensional expansion of the velocity field is existed and unique and velocity filed is an equivalent representation of the three-dimensional circumfluence functions. In addition, the vertical velocity and its components can reflect the main characteristics of the vertical circumfluence.