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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/2335
標題: | 浮標觀測颱風中心附近海域的海氣象變化之研究 Investigation of data buoys observed sea surface atmosphere and upper ocean variations during typhoons |
作者: | Chia-Ying Hsieh 謝佳穎 |
指導教授: | 楊穎堅 |
關鍵字: | 海氣象浮標,颱風,熱通量,近慣性運動,混合過程, Air/sea-observing buoy,Typhoon,Heat flux,Near inertial motion,Mixing process, |
出版年 : | 2017 |
學位: | 碩士 |
摘要: | 西北太平洋為颱風生成的熱區,此海域的颱風較其他海域多且強。颱風生命週期中,大多時間滯留於海面上,因此除了當時的大氣環境會影響其生長,海洋狀態亦非常重要,若能即時掌握上層海洋的改變,將有助於改善對颱風強度的預報。本研究利用國立臺灣大學海洋研究所的海氣象即時傳輸浮標,在2015和2016夏天於鵝鑾鼻東南方海域約375與175公里處,進行測試實驗時所收集到的資料,搭配衛星遙測資料與數值模式資料討論颱風造成的海洋變化。在觀測期間內,計有2015年的蓮花、昌鴻、蘇迪勒與天鵝;及2016年的尼伯特、莫蘭蒂、馬勒卡、梅姬與艾利,等9個颱風經過附近海域,其中NTU1和NTU2站分別進到馬勒卡與尼伯特颱風的颱風眼範圍內。在分析後得到以下結論:慣性運動在颱風逐漸靠近即開始形成,且颱風的到達時間點會影響慣性流之大小。此外,近慣性運動週期除了可能受到背景場或渦旋影響外,亦可能受到颱風尚在南邊時的影響,致使觀測所得之慣性週期略大於當地慣性週期。在強烈颱風靠近時,會因強風造成的流切不穩定使混合層之厚度可以在5小時內增加100公尺,且可能為了維持位渦守恆,使颱風來時所造成之厚的混合層,在颱風中心離開後隨即快速變薄。此外,在颱風中心通過之後,因水平平流帶來颱風左側之較暖的海水,使表層海洋有回溫現象。 Western North Pacific is the most active area for typhoons in the world. To understand the changes of upper ocean is necessary for optimizing the typhoon intensity forecasts. In summer of 2015 and 2016, the Institute of Oceanography, National Taiwan University (IONTU) deployed two air/sea-observing buoys at distances of approximately 375 km (station NTU1) and 175 km (station NTU2) from the southernmost tip of Taiwan. During the trails, buoys survived nine typhoons (Linfa, Chanhom, Soudelor, Goni, Nepartak, Meranti, Malakas, Megi, and Aere). Among them, the stations NTU2 and NTU1 almost coincided with the paths of typhoon Nepartak and Malakas, respectively. In this research, buoy data, satellite and numerical model products were used to figure out the ocean responses resulting from typhoon. Observation data shows two major conclusions. First, the near inertial motion started when typhoon approached, and the arrival time could be related with magnitude of inertial current speed. Furthermore, the observed inertial period was larger than local inertial period. It is probably related to interactions between near- and sub-inertial currents or the inertial motion generated at the southern side of buoy. Second, the thickness of mixed layer increased 100m in 5 hours by current shear instability. Besides, the thickness of mixed layer rapidly decreased after typhoon’s center has passed. It could be related to potential vorticity conservation. Moreover, the temperature of sea surface increased is due to the horizontal advection. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/2335 |
DOI: | 10.6342/NTU201703398 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 海洋研究所 |
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檔案 | 大小 | 格式 | |
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ntu-106-1.pdf | 9.58 MB | Adobe PDF | 檢視/開啟 |
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