光達遙測中壢地區夜間邊界層變化和低層噴流之討論

Evolution and Changes of Nocturnal Boundary Layer at Chung-Li by Lidar Measurements

江智偉(Chih-Wei Chiang) ； 倪簡白(Jan-Bai Nee)

《大氣科學》 35卷1期 (2007/03) Pp. 1-11

摘要

在邊界層中由於空氣的擾動使光達(lidar)量測氣膠(aerosols)背向散射訊號時會出現擾動的現象，因此利用這個光達訊號擾動特性，我們可用來決定邊界層高度與即時的演化過程。本文主要分析中央大學在2002~2004年間利用光達測量低空氣膠的擾動變化，發現中壢地區夜間邊界層高度呈現夏季高度高、冬季高度低的季節性變化，此季節性和高度變化分佈會影響氣膠光學厚度和地面污染物之濃度。除此之外，在垂直高度的分佈上我們也發現高度1-2.5公里間常有數層的氣膠擾動層存在，此低空擾動層主要發生在春、冬季節。這些低空擾動層常伴隨低層噴流(low level jet)的出現。

關鍵字

光達 ； 氣膠 ； 邊界層 ； 低層噴流

並列摘要

Aerosol backscattering signals show large fluctuation resulting from the turbulence of air in the boundary layer. By using this property, heights and evolutions of boundary layer can be determined. Using Lidar we measured aerosol in the past three years 2002-2004 and found that the nocturnal boundary layer in Chung-Li with a higher height in summer and lower in winter. The aerosol optical depth and concentration of ground pollutants have been affected by the seasonal and height variation of nocturnal boundary layer. There are several turbulence layers which appeared frequently in spring and winter seasons around 1-2.5 km height region. Comparing with Radiosonde data, we found those turbulence layers are related to a low-level jet.

並列關鍵字

Lidar ； Aerosol ； Boundary layer ； Low-level jet