Wind Speed Profiles of Typhoon Matmo Observed Using Doppler Lidar

督卜勒光達麥德姆颱風風速剖面觀測

蔡原祥(Yuan-Shiang Tsai) ； 楊雅兆(Ya-Chao Yang) ； 張宛婷(Wan-Ting Chang) ； 楊文昌(Wen-Chang Yang) ； 林博雄(Po-Hsiung Lin) ； 陳景林(Jin-Lin Chen)

《海洋工程學刊》 17卷1期 (2017/03) Pp. 1-20

摘要

The wind speed and turbulence intensity profile of typhoon Matmo was measured using a ground-based Doppler Lidar at Hsingda Harbour, south Taiwan in 2014 with the measurement height between 48 and 268 m. Under the relatively strong wind speed exceeding 10 m/s in the atmospheric neutral stability, four types of wind profiles are observed, which are: 1. development of a logaritlunic layer for the entire observation height; 2. significantly affected by Coriolis force and deviation to the logaritlunic profile above the surface layer; 3. in existence of a gradient height close to the surface; 4. formation of low level jet in the rainfall condition. Besides, the present study shows that a two-layer model using the power law to fit the lower and upper layer respectively is appropriate to describe the evolution of the hourly mean wind speed profile as well as the turbulence intensity profile.

關鍵字

Typhoon boundary layer ； turbulence intensity ； atmospheric surface boundary layer ； power law

並列摘要

於台灣南部興達港使用督卜勒光達(Doppler Lidar)於2014年量測颱風麥德姆颱風的風速與紊流強度剖面分佈，測量高度介於48至268 m。在風速較強，大於10 m/s的大氣中性穩定條件下，觀測到四種型態風速剖面：1.所量測高度區間風速邊界層的發展完全符合對數型態風速剖面；2.明顯受科式力影響，高度大於表面層(surface layer)時，風速偏離對數型態剖風速剖面；3.存在一梯度高度(Gradient height)的淺層邊界層；4.在降雨的條件下，形成類似於低空噴流型態。本研究顯示，使用指數型態進行最適合化曲線，兩層模式(two-layer model)在邊界層上、下層各自有一獨立的冪指數，較能描述平均風速與紊流強度垂直分佈的演變。

並列關鍵字

颱風邊界層 ； 紊流強度 ； 大氣近地表邊界層 ； 指數公式