台灣松山機場低空風切警告系統與低空風切診斷分析

The Low-level Wind Shear System and the Diagnosis of Low-level Wind Shear at Sungshan Airport in Taiwan

蒲金標(Chin-Piao Pu)

《大氣科學》 31卷2期 (2003/06) Pp. 181-198

摘要

本文使用2001年9月至2002年8月民航局松山機場低空風切警告系統(Low Level Windshear Alert System; LLWAS)之觀測資料，分析與探討其低空風切之發生。初步研究結果現，松山機場發生低空風切，輕度和中度各約佔半數，強烈者甚少。雖然發生強烈低空風切甚少，但對飛機起降之危害甚大，應給予重視。
夏季6~8月受颱風和午後雷陣雨，初秋9~10月受颱風、東北季風和鋒面過境，深秋、冬季和春季11~5月受東北季風和鋒面過境等影響，機場都會有低空風切現象，其中以颱風和午後雷陣雨引發最多且最強烈的低空風切。
松山機場每天上午9時至下午16時發生低空風切之頻率大於平均值，其中以上午11時至下午15時發生風切頻率為最高，上午8時和下午17時發生風切頻率則次之，而每天下午18時至翌日上午7時發生低空風切之頻率最小。
機場發生低空風切之天氣類型，以東北季風型之天數為最多，西南季風型次之，颱風環流型風環流型次之，東北季風型和鋒面過境型再次。松山機場因雷雨陣風、颱風強風、鋒面過境以及強烈東北季風等風場改變大是為引發低空風切之主因。

關鍵字

低空風切警告總統 ； 低空風切 ； 鋒面過境型 ； 東北季風型 ； 颱風環流型 ； 西南季風型 ； 徵爆氣流

並列摘要

CCA’s Low-Level wind shear Alert System (LLWAS) at Sungshan Airport has been in operation since September 2001. In this study, the LLAWS data for the time period September 2001 – August 2002 are used for analyzing and discussing the occurrences of low-level wind shear. The statistics shows that most of the observed low-level wind shear warnings at Sungshan Airport are categorized either light or moderate with just about the same percentage of occurrence. Severe wind shear warnings were relatively rare but could not be overlooked since they could be a major safety concern for aircraft taking off or making a landing.
Analysis of weather systems associated with the occurrence of low-level wind shear indicated that typhoons and afternoon thunderstorms occurred in the summer (June-August); typhoons, northeast monsoons, and frontal passages occurred in the early fall (September-October); and northeast monsoon and frontal passage occurred in both winter and spring (November-May) are the major weather types. Typhoons and afternoon thunderstorms weather systems caused the largest number and also the severest low-level wind shear.
The hourly statistics of low-level wind shear at Sungshan Airport indicates that the hourly occurrences between 9AM and 4PM above average. The highest occurrences are between 11AM and 3PM, followed by occurrences at 8AM and 5PM. Between 6PM to 7AM the next day, the frequency of low-level wind shear occurrence are the lowest.
The weather types associated with moderate and server low-level wind shear warnings at Sungshan Air port are categorized as northeast monsoon type (for the most cases), southwest monsoon type (for the modest cases), typhoon circulation type, and frontal passage type (for the fewest cases), However, as for sever low-level wind shear alone, the weather types in descending order are southwest monsoon type, typhoon circulation type, northeast monsoon type, and frontal passage type. In summary, major causes of low-level wind shear warnings at Sungshan Airport, in descending order of occurrences, are thunderstorm gusts, typhoon gust, significant wind shift during frontal passages, and strong northeast monsoons.

並列關鍵字

Low Level Wind shear Alert System ； Low Level Wind Shear ； Frontal passage type ； Northeats monsoon type ； Typhoon circulation type ； Southwest monsoon Type ； Microburst