動力能量效率及長生命雙眼牆颱風

2014-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/708575摘要：本計畫研究重點共分三大項，第一部分為長生命的雙眼牆颱風動力探討，第二部分為動力能量效率的廣泛應用，第三部分著重於將柴比雪夫(Chebyshev)法應用至全球模式中的平流過程。延續過去在雙眼牆結構變化的研究成果，我們發現約25%雙眼牆颱風有相對緩慢的眼置換過程（平均31 小時），因此第一部份工作，我們將探討生命期雙眼牆颱風動力，將利用不同複雜程度的動力模式進行研究，我們將利用加入潛熱外力作用的淺水方程式與等熵靜力平衡模式，以及完整物理的CReSS 或WRF 模式進 行研究；相較完全複雜模式或正壓模式，中間複雜程度的模式能更精簡的詮釋熱力驅使下的渦旋動力 作用及影響。第二部分為動力能量效率的廣泛應用，此動力能量效率的公式建立於梯度風平衡動力架構上，我們將使用新推導的動力能量效率工具深入探討雙眼牆發展過程的動力問題。我們的假說是：雙眼牆的形成時，moat 初現使得能量效率大幅增加。將使用動能效率診斷分析模擬資料，設計結合觀測的理想型動力渦旋實驗，探討基本動力問題；接著與雷達資料結合，討論雷達資料對於效率的敏感 度；更廣泛地，使用雲模式之模擬結果，討論軸對稱/非軸對稱颱風在其發展過程中動能效率的異同，幫助深入了解雙眼牆動力。此工具也可應用於大氣不同尺度的科學問題，我們也將推導球面座標的能 量效率方程式。第三部分著重於將柴比雪夫(Chebyshev)法套用至全球模式平流過程中，此數值方法具指數收斂特性，並可減少Runge 現象、減少邊界誤差，並可以使用FFT，搭配區域切割以有效節省計算時間，預期能利用此計算方法，或是其他高效率波譜有限元方法，進行球面平流擴散方程計算，以診斷大氣有效擴散率，結合水氣觀測，以提升大氣水氣混合監測，瞭解水氣混合對於颱風動力或MJO 動力的影響。<br> Abstract: This proposal contains the research of three major components: 1) long-lived concentric eyewalls (CE) typhoon dynamics; 2) dynamic energy efficiency diagnosis study; 3) application of Chebyshev spectral method or other efficient numerical method such as spectral element method to the advection and diffusion equation on the global scale to study the eddy diffusivity. In the long-lived CE study, we proposed to use dynamical models of complexity hierarchy, such as the shallow water model, the primitive equation with isentropic coordinate, and the CReSS or WRF models to study the long-lived CE typhoons with very large moat and large outer eyewall width. Our hypothesis is the formation of moat is the key for the energy efficiency of the CE typhoons. To better understand this, this leads to the development of the dynamic energy efficiency diagnosis. The efficiency is derived with the gradient wind balanced frame work. We will use the idealized model, aircraft radar data, and the CReSS model output to demonstrate the usefulness of the energy efficiency. Moreover, we will work on the generalization of the formula to the spherical geometry. In the last part, we will use the Chebyshev spectral method or other high efficient method such as spectral element method to study the advection-diffusion equation on the sphere, to calculate the eddy diffusivity. The Chebyshev spectral method reduce the Runge phenomena and allow the use of FFT, thus may be very efficient. We will use the eddy diffusivity and water vapor information to study the impact of water vapor mixing on phenomena such as typhoon or MJO weather system.長生命雙眼牆動&#63882能&#63870效&#63841柴比雪夫(Chebyshev)波譜法波譜有限元方法有效擴散&#63841long-lived concentric eyewalls typhoondynamic energy efficiencyChebyshev spectral methodspectral動力能量效率及長生命雙眼牆颱風