聖嬰現象與赤道大氣克耳文波之可能關聯

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Title:	聖嬰現象與赤道大氣克耳文波之可能關聯
Authors:	楊欣哲;Yang,Sin Che
Contributors:	太空科學研究所
Keywords:	赤道大氣克耳文波;聖嬰現象;對流;準兩年震盪;Equatorial Atmospheric Kelvin waves;El Niño;convection;Quasi-biennial oscillation
Date:	2016-07-04
Issue Date:	2016-10-13 12:55:05 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究使用了1979年至2015年歐洲中心中程數值天氣預報以及福爾摩沙衛星三號之大氣溫度場及風場資料分析赤道大氣克耳文波，並使用二維離散傅立葉轉換將克耳文波以水平波數及週期分解，短週期之克耳文波(5、8及12天週期)具有較長之垂直波長不受平流層風場之限制而上傳，但長週期之克耳文波除了16天週期之克耳文波可於準兩年震盪西風相位即將結束時上傳外，19及24天週期之克耳文波僅在東風時活躍，此外，上傳的克耳文波在東風轉西風之零風場線下發生波破碎，使得振幅變大，波動能量部分傳遞至背景風場。　　根據NOAA衛星的出長波輻射資料以及TRMM衛星的降水資料顯示，自印尼地區移動至中太平洋的東向深對流區則增強了16公里至18公里高度的克耳文波，在聖嬰事件期間，雖然對流型態有所改變，但仍然增強了克耳文波，且僅發生於風場為東風或西風相位即將結束之時期，2010年的案例則因克耳文波上傳至40公里高度導致準兩年震盪風場的由東風快速轉換為西風，但其他在聖嬰事件年份的案例無法僅能傳至25公里至30公里高，因此影響程度有限。 ;The atmosphere temperature and zonal wind data from 1979 to 2015 which offered by European Centre for Medium-Range Weather Forecasts and FORMOSAT-3 data are used to analysis the atmospheric equatorial Kelvin waves. Than we use the two dimension fast discrete Fourier transform (2D-FFT) to separate the Kelvin waves to different zonal wavenumber and period. Short period Kelvin waves (5, 8 and 12 days) have more longer vertical wavelength so that they can propagate upward without restriction by background zonal wind. But long period Kelvin waves only 16 days Kelvin waves can upward propagate during the end of the Quasi-biennial oscillation (QBO) westerly phase, 19 and 24 days Kelvin waves only active when during QBO easterly phase. Otherwise, upward propagation Kelvin waves will break below the zero wind line (easterly wind to westerly wind) and let the amplitude be larger. The part of energy will transfer to the zonal wind. NOAA-OLR (outgoing longwave radiation) TRMM-rainfall data indicate the eastward moving deep convection zone which moving from Indonesia to Central Pacific ocean enhanced the Kelvin waves at 16-18 km. During the El Niño Southern Oscillation (ENSO) period, although the feature of deep convection zone have been changed, but still enhance the Kelvin waves. And the phenomenon happen when the end of the QBO westerly phase or easterly phase. The Kelvin waves upward propagate to 40 km and let the direction of QBO turn fast from easterly to westerly in 2010 case. In other cases, the Kelvin waves only can propagate to 25-30 km, so they cause little influence to QBO.
Appears in Collections:	[Graduate Institute of Space Science] Department of Earth Sciences

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