- 作者: 張隆男
- 作者服務機構: 國立中央大學大氣物理系
- 中文摘要: 本文將有限地區大氣動能控制方程以單正交函數(Orthonormal function)轉換至波數空間,並利用1962年3月20?21 兩天格林威治0時與12時,北美氣旋發展個案之雷文送探空資料,?究中緯度氣旋發展過程中,大規模大氣波動之動能交換情形。 結果顯示,氣旋波的消長與氣旋系統的發展有密切關係。在發展期氣旋波的能量隨時間增加,至成熟期達最大?,囚錮 其則強度減弱。較短的氣旋波(波數10?12)之發展主要由於順氣壓梯度流所生之動能及水平邊界之動能輸入,而較長氣旋 波(波數7?9)之動能則有賴小尺度之動能供應,大氣波動間動能之非線性交換視氣旋發展階段之不同而有很大差異;在 發展期與成熟期動能由氣旋波供應其他較長及較短的大氣波,然而在囚錮期,非線性交換的方向相反,動能由其他大氣波向 氣旋波輸入。本研究結果並顯示,格點尺度(Grid-scale)與次格點尺度(Subgrid-scale)波動間之非線性交換對大規模大氣 波動之消長有重要的影響。
- 英文摘要: The kinetic energy transfer of large-scale atmospheric waves during a period of cyclone development is examined by decomposing the total kinetic energy budget into various eddy components. Rawinsonde data taken at 0000 GMT and 1200 GMT for a two day period (March 20-21, 1962) spanning the developing, mature and occluded stages of the cyclone is used in this study. A positive correlation is found between the intensification and decay of cyclone-scale waves and the cyclone development. The amplitude of the cyclone waves increases during the developing stage, reaches a maximum at mature stage and decays by the occluded stage. The shorter cyclone waves (wave number 10-12) grow by cross-isobaric generation and horizontal import of kinetic energy, while the longer cyclone waves (wave number 7-9) intensify through nonlinear interactions between grid and subgrid-scale processes. During the examined life history of the cyclone, the kinetic energy was constantly redistributed among various scales of waves due to nonlinear interactions. In the developing and mature stages, cyclone waves contribute energy to both longer and shorter waves, while during the occluded stage, these waves receive energy from other waves. An examination of dissipation term reveals the importance of nonlinear interactions between grid-scale and subgrid-scale waves for the evolution of large-scale atmospheric waves.
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