透過您的圖書館登入
IP:44.200.77.59
  • 期刊

TAMEX IOP-2颮缐之結構特徵研究

Study on the Structural Characteristics of the TAMEX IOP-2 Squall Line

摘要


本文使用台灣地區中尺度實驗計畫(TAMEX)密集觀測網之資料,研究IOP-2期間(1987年5月16-17日)通過台灣地區之颮線個案,除探討系統之結構特徵,並分析地面附近在颮線通過前後伴隨之天氣現象。結果顯示,本個案對流帶呈南北走向,由台灣海峽快速向東移入西部沿海與山區,平均移速達16m s^(-1)。成熟期之系統,可辨認出具有許多與中緯度及熱帶颮線相似之內部結構特徵,包括前方暖濕內流、後方較乾之中低層內流。降水結構則由前向後具有颮前砧狀雲、強對流窄帶、過渡帶、及拖曳層狀降水區。近地面處之中尺度擾動,則包括颮前低壓、陣風鋒面、伴隨冷池之中尺度高壓、以及後方之尾流低壓等均可分辨。 地面伴隨陣風鋒面通過之各氣象要素變化,在本個案相當明顯,包括風向急變、風速突增、氣壓先驟升後緩降、溫度與露點突降,並有強度較大的對流性降水,之後有持續但和緩之層狀降水,充分顯示典型颮線之降水結構特徵。由於系統移速快,陣風鋒面前方有顯著且深厚之暖濕內流,並進而產生旺盛之後方內流,此為本個案與一般副熱帶颮線的主要差異,亦為導致地面附近具顯著中尺度擾動的主因。當IOP-2颮線登陸後,由於受到地形的阻滯作用,移動速度減緩,系統並在喪失前方暖濕內流的水氣供應後迅速減弱。由於本個案移速快且移入後強度減弱,故整體而言並未造成豪雨。

並列摘要


The present study employs data collected during the second Intensive Observing Period(IOP-2)in the Taiwan Area Mesoscale Experiment (TAMEX) to investigate the squall line occurred in May 16-17, 1987. Structural characteristics of the system are discussed and the atmospheric responses near the surface are documented. It is found that the squall line had a north-south orientation, and moved eastward rapidly from the Taiwan Strait onto the island of Taiwan, at a speed of about 16ms^(-1). Many structural characteristics typical to mid-latitude and tropical cases are found in the present subtropical squall line in its mature stage. These include a storm-relative front-to-rear inflow of warm and moist air, and a drier rear-to-front inflow at lower-to-middle levels. From front to rear, features in precipitation structure include the pre-squall anvil, the intense and narrow convective band, the transition zone, and the trailing stratiform region. Near the surface, mesoscale disturbances such as the pre-squall low, the gust front, the mesohigh (in association with a cold pool), and the wake low are all discernible in the present case. As the gust front passed through, clear responses were recorded at the surface, including shifting in wind direction, rapid increase in wind speed, abrupt pressure rise followed by steady fall, as well as sudden drop in both temperature and dew-point. The most intense convective precipitation occurred immediately after gust front passage, and relatively weak but persistent stratiform-type precipitation followed. Due to the fast speed of the system, the front-to-rear inflow was both strong and deep, bringing abundant warm and moist air into the system. This led to a rear inflow jet considerably stronger than in most subtropical cases, and eventually contributed to the significant responses at the surface. When the IOP-2 squall line made landfall, its propagation speed decreased due to terrain blocking, and the system weakened rapidly as it moved into the mountainous area and lost moisture supply. Due to the fast movement and subsequent weakening of the case, the overall rainfall in Taiwan did not reach the standard for heavy rain events.

被引用紀錄


黃心怡(2009)。梅雨季台灣中部豪雨個案分析與模擬〔碩士論文,國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342%2fNTU.2009.01640
林偉文(2010)。雙颱環境下台灣海峽中尺度線狀對流之個案研究〔碩士論文,國立臺灣師範大學〕。華藝線上圖書館。https://www.airitilibrary.com/Article/Detail?DocID=U0021-1610201315202157

延伸閱讀