跳到主要內容

臺灣博碩士論文加值系統

(44.213.60.33) 您好!臺灣時間:2024/07/17 04:10
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

: 
twitterline
研究生:蔡宗樺
研究生(外文):Zong-hua Tasi
論文名稱:利用WRF模式探討台灣東部海上對流線之個案研究
論文名稱(外文):Cases syudy of convective lines over the eastern sea surface of Taiwan by WRF model
指導教授:林沛練林沛練引用關係
指導教授(外文):Pay-Liam Lin
學位類別:碩士
校院名稱:國立中央大學
系所名稱:大氣物理研究所
學門:自然科學學門
學類:大氣科學學類
論文種類:學術論文
論文出版年:2012
畢業學年度:100
語文別:中文
論文頁數:125
中文關鍵詞:福祿數地形噴流羅士比半徑
外文關鍵詞:Froude numberBarrier jetRossby radiusBurger number
相關次數:
  • 被引用被引用:7
  • 點閱點閱:300
  • 評分評分:
  • 下載下載:38
  • 收藏至我的研究室書目清單書目收藏:0
台灣冬季弱綜觀環境下東部海面上常觀測到線狀對流的發生。這些對流線多呈東北-西南或南-北走向,且平行於海岸線,通常發展於近海地區(<40 km),但有些對流線能發展於外海地區(>40 km)。由先前的研究中提出,沿海地區的離岸流與大環境的向岸流所導致的低層輻合為近海對流線主要的生成機制。然而對於發展於外海的對流線,不同的個案之生成物理機制似乎有不同的說法。因此地形效應所造成地形回流或地形噴流是否可造成外海對流線生成,以及是否有其他原因導致對流線生成,為本研究主要探討內容。由於海洋地區缺乏觀測資料,增加其研究難度,因此本文藉由高解析數值模式來探討其對流線之動力生成機制。
 本研究利用美國國家大氣研究中心(NCAR)的WRF(Weather Research and Forecasting)數值模式進行模擬,水平網格解析度分別為40.5,13.5,4.5,1.5 km,並配合不同觀測資料進行驗證。選定三個個案2004/01/03,2006/12/11,2008/10/29,三個個個案發生時上游風場有所不同,且對流生成位置皆不相同,本研究藉由此三個個案,詳細探討台灣東部近海和外海對流線的生成機制與對流線特徵。模擬結果顯示,三種個案其主要生成機制皆有所不同,但都與台灣的地形效應有密切相關。個案一形成機制為,上游氣流受到山脈阻擋,使得對流線左側有地形噴流造成較強的北風,而對流線東側為東北風,此兩個不同方向之氣流,在外海約50 km處產生輻合,激發出對流線。個案二的生成原因為盛行風受到山脈阻擋,導致氣流無法過山,因此在山前形成地形回流與地形繞流(西南風)。而兩種機制產生之離岸流,再跟大尺度風場在外海低層輻合,生成對流線。個案三的生成機制為夜間局部環流和大尺度風場兩反向氣流在近海附近輻合,外加上850 hPa這層於成功沿岸附近有區域性的風切輻合,增強中層對流線發展,此個案生成機制與台灣東部局部環流有較大相關性。
本研究另外設計台灣地形高度敏感度實驗,將台灣地形高度降低50%(TER50 RUN)後,模擬結果顯示,東部山脈阻擋效應較不明顯,部分氣流容易直接過山,不論是地形作用或局部環流所引發之離岸流皆比(CTRL RUN)較微弱,間接導致對流線生成位置靠近岸邊,生命週期也較短。而當地形高度降至0%(TER00 RUN)時,對流線左側離岸氣流消失,無離岸氣流可維持對流生成,對流線隨之消散掉,可見台灣地形是影響對流線生成與發展的關鍵因素之一。
Under weakly synoptic weather conditions, the occurring of convective lines are often observed over the eastern sea surface of Taiwan in the winter. These convective lines are oriented northeast – southwest or south – north direction and approximately parallel to the coastline. Additionally, these lines usually develop near the coast (<40 km) but they could develop off the coast (>40 km) occasionally. The main purpose of the study is to discuss the main formation mechanism of convective lines which developed far from the coast. Whether the orographic effects resulted in terrain returned airflow or barrier jet will be investigated in this study. Since, the lacking of observation data over the ocean area increases the difficulty of observational study, so this study aims to investigate these questions by high-resolution numerical model.
This study conducts simulation by WRFV 3.2.1 (Weather Research and Forecasting) numerical model and validates with different observation data. Four nested domains were used with horizontal resolutions of 40.5, 13.5, 4.5 and 1.5 km, respectively. Three different types of case are chosen, the first one is the case Jan. 3 in 2004, the second is the case Dec. 11 in 2006 and the third is the case Oct. 29 in 2008. The formation mechanism of the first case (200401) is that the airflow in the upstream was blocked by mountains so that barrier jet formed on the west side of convective lines, and resulted in stronger northly winds. Since, there are north-easterly winds prevailed in the east side of convective lines; these two different directions of flows collide and converge about 50 km off the coast, to stimulate initiation of the convective lines. The formation mechanism of the second case (200612) is blocking of prevailing winds by mountains so that prevailing winds couldn’t across mountains. Therefore, there are terrain returned airflows and terrain around flows (south-westerly winds) forming in front of mountains. These two different terrain induced flows could formation of converge with large scale prevailing wind in the low level off the coast, and lead to the convective lines. The formation mechanism of the third case (200810) is the local circulation during the night time and the large scale prevailing wind which are two reverse flows converge near the coastal area. Additionally, regional wind shear convergence enhance the development of mid-level convective line near the coast of Cheng Kung in the 850 hPa.
This study also designs the sensitivity test besides the control simulation with real terrain of Taiwan (referred to as CTRL), we conducted simulations with reduced terrain of 50% (TER50) and 0% (TER00) of the real terrain. The sensitive test shows that when the terrain height is reduced, the blocking of terrain is not obvious, and part of airflows will cross mountains. Therefore, the reduced orographic effects caused the offshore flow weaker than CTRL; the forming position of convective lines near the coast , and the life cycle is shorter. This sensitive test could confirm one of the key factors to the control formation and development of convective lines is terrain height.
摘要 I
致謝 V
目錄 VI
表目錄 VIII
圖表目錄 IX
第一章 序論 1
(一)前言與文獻回顧 1
(二)研究動機 3
第二章 觀測資料與研究方法 5
(一)本研究使用資料 5
(二)模式簡介 6
(三)模式設定 7
(四)實驗設計 9
第三章 個案分析與結果討論 10
(一)個案一 綜觀天氣與觀測資料分析 10
(二)個案一 模擬結果比對、分析與討論 12
1. 大尺度環境場與雷達回波分析與比較 12
2. 垂直剖面與生成機制分析 14
3. 降低台灣地形之敏感度實驗 15
(三)個案二 綜觀天氣與觀測資料分析 16
(四)個案二 模擬結果比對、分析與討論 19
1. 大尺度環境場與雷達回波分析與比較 19
2. 垂直剖面與生成機制分析 21
3. 降低台灣地形之敏感度實驗 23
(五)個案三 綜觀天氣與觀測資料分析 24
(六)個案三 模擬結果比對、分析與討論 26
1. 大尺度環境場與雷達回波分析與比較 26
2. 垂直剖面與生成機制分析 28
3. 降低台灣地形之敏感度實驗 29
第四章 結論與未來展望 31
(一)結論 31
(二)未來展望 33
第五章 參考文獻 34
附表 38
附圖 41
呂玉璇,2003:台灣東南部地區局部環流與邊界層特性之研究。國立中央大學大氣物理
研究所碩士論文,1-99。
邱思翰,2010:利用WRF模式研究SoWMEX IOP3期間地形效應對於強降雨個案之影響。
國立中央大學大氣物理研究所碩士論文,1-96。
林哲佑,2007 :台灣東南沿海對流線雷達觀測之氣候特徵分析。私立中國文化大學地學
研究所大氣科學組碩士論文,1-78。
許郁卿,2011,土地利用型態對地表能量收支與海陸風模擬的影響。國立中央大學大氣
物理研究所碩士論文,1-101。
黃偉銘,2007:台灣東南方近海線狀對流之個案模擬。私立中國文化大學地學研究所大氣
  科學組碩士論文,1-112。
曾德晉,2011,台灣東南部冷季淺對流分析研究。私立中國文化大學地學研究所大氣科
  學組碩士論文,1-146。
錢之駿,2003:台灣東南部地區複雜地形局部環流的模擬研究。國立中央大學大氣物理研
究所碩士論文,1-66。
Alpers, W., J, -P Chen, I. –I. Lin, and C. -C Lin, 2007: Atmospheric fronts along the east coast of Taiwan studied by ERS synthetic aperture radar images. Mon. Wea. Rev., 64, 922-937.
_________, J.-P. Chen, C. -J. Pi, and I. -I. Lin 2010: On the Origin of Atmospheric Frontal Lines off the East Coast of Taiwan Observed on Spaceborne Synthetic Aperture Radar Images. Mon. Wea. Rev., 138 , 475-496.
Banta, R. M., 1990: The role of mountain flows in making clouds. Atmospheric Processes
over Complex Terrain, Meteor. Monogr., No.45, Amer. Meteor. Soc., 229-284.
Chen, C.-S., and Y.-L. Chen, 2003: The rainfall characteristics of Taiwan. Mon. Wea. Rev., 131, 1323-1341.
__________, W. –S. Chen, and Z. –S. Deng, 1991: A study of a mountain-generated precipitation system in northern Taiwan during TAMEX IOP 8. Mon. Wea. Rev., 131, 1323-1341.
Chien, F.-C., and Y. –H. Kuo, 2006: Topographic Effects on a Wintertime Cold Front in Taiwan. Mon. Wea. Rev., 134, 3297-3316.
Chen, Y.-L., and J. Feng, 2001: Numerical simulations of airflow and cloud distributions over the windward side of the island of Hawaii. Part I: The effects of trade-wind inversion. Mon. Wea. Rev. 129, 1117-1134.
Kerns, B., Y.-L. Chen and M.-Y. Chang 2010: The diurnal cycle of winds, rain and clouds over Taiwan during the Mei-Yu, Summer, and Autumn regimes. Mon. Wea. Rev. 138, 497-516.
Li, J., and Y.-L. Chen, 1998: Barrier jets during TAMEX. Mon. Wea. Rev., 126, 959-971.
Lin, P.-L., Y.-L. Chen, C.-S. Chen, C.-L. Liu, and C.-Y. Chen, 2011: Numerical experiments investigating the orographic effects on a heavy rainfall event over the northwestern coast of Taiwan during TAMEX IOP 13. Meteorol Atmos Phys, 114, 35-50.
Murphy, M J., and S. Businger, 2011: Orographic Influences on an Oahu Flood . Mon. Wea. Rev., 139, 2198-2217.
Overland, J. E., and N. A. Bond, 1995: Observations and Scale analysis of coastal wind jet. Mon. Wea. Rev., 123, 2934-2941.
Smolarkiewicz, P. R., R. M. Rasmussen, and T. L. Clark, 1988: On the dynamics of Hawaiian cloud bands : Island forcing. J. Atmos. Sci., 45, 1872-1905.
U.S. Depts. Of Commerce and Defense, 1980: Weather radar observations Part A. federal meteorological handbook, No. 7, 5-1---5-2.[Available from National Center for Environmental Prediction, Suitland, MD]
Wang, C. -C, Chen, G. T. -J., T. -C. Chen, and K. Tsuboki, 2005: A numerical study on the effects of Taiwan topography on a convective line during the Mei-yu season. Mon. Wea. Rev., 133, 3217-3242.
Wang, J.-J., and Y.-L. Chen, 1998: A case study of Hawaiian trade-wind rainbands and their interaction with the island-induced airflow. Mon. Wea. Rev., 126, 409-423.
Yang, Y., and Y.-L. Chen, 2008: Effects of terrain heights and sizes on island-scale circulations and rainfall for the island of Hawaii during HaRP. Mon. Wea. Rev. 136, 120-146.
Yeh, H. -C., and Y. -L. Chen, 1998: Characteristic of rainfall distribution over Taiwan during TAMEX. J.Appl. Meteor., 37, 1457-1469.
_________, and __________, 2002: The role of offshore convergence on coastal rainfall during TAMEX IOP 3. Mon. Wea. Rev., 130, 2709-2730.
Yu, C. -K., and B. J. -D. Jou, 2005: Radar observation of diurnally forced, offshore convective lines along the southeastern coast of Taiwan. Mon. Wea. Rev., 133,1613-1636.
_________, and C. -Y. Lin, 2008: Statistical location and timing of the convective Lines off the mountainous coast of southeastern Taiwan from long-term radar observations. Mon .Wea. Rev., 136, 5077-5094.
_________, and Y. -H. Hsieh, 2009: Formation of the convective Lines off the mountainous coast of southeastern Taiwan : A case study of 3 January 2004. Mon. Wea. Rev., 137, 3072-3091.
Zhang, Y., Y.-L. Chen, T. A. Schroeder, and K. Kodama, 2005: Numerical simulations of sea breeze circulations over northwest Hawaii. Wea. Forecasting , 20, 827-846.
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top