Acoustic remote sensing study of the influence of internal gravity waves on the lower atmosphere

内部重力波对低层大气影响的声学遥感研究

• 批准号: 5409049
• 负责人: Dr. Astrid Anita Ziemann
• 金额: --
• 依托单位: A.M.Obukhov Institute of Atmospheric Physics
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5409049?language=en
• 关键词: Acoustic; remote; sensing; study; influence

It is recognized that atmospheric internal gravity waves (IGW) generated from various random sources significantly contribute to the power spectrum of the wind speed and temperature fluctuations in the Atmospheric Boundary Layer (ABL) within a broad range of time and spatial scales. However, the statistical characteristics of the wind speed and temperature fluctuations induced by IGWs are not well studied, although these fluctuations were found to play a substantial role in the dynamics and turbulent regime of the stable ABL. The main objective of the proposed project is to investigate the spatial structure and statistical characteristics of the meso-scale wind speed and temperature fluctuations in the ABL with the space-time scales inherent to atmospheric IGWs. For this purpose the following tasks are outlined in the project: 1) The experimental study of the effects of meso-scale wind speed and temperature fluctuations on the parameters of the acoustic signals propagating under stable conditions of the ABL: 2) The measurement of meso-scale fluctuations of wind speed and temperature by means of acoustic tomography combined with vertical acoustic sounding of the ABL under stable stratification of the ABL. To solve these tasks a new approach is proposed based on a combined use of different schemes of acoustic tomography (horizontal and vertical slice schemes) and of additional vertical acoustic sounding of the ABL. These acoustic remote sensing methods complement each other and allow to reconstruct the wind speed and temperature fields within both horizontal slices (300 x 300 qm) and vertical slices (300 m above surface) of the ABL. The results obtained will fill a gap in our knowledge of the properties of meso-scale atmospheric turbulence and will help to parameterize stable ABL in general circulation and air-pollution transport models.

各种随机源产生的大气内部重力波（IGW）对大气边界层（ABL）风速和温度波动的功率谱在大范围的时间和空间尺度上有重要贡献。然而，igw引起的风速和温度波动的统计特征尚未得到很好的研究，尽管这些波动在稳定ABL的动力学和湍流状态中起着重要作用。本项目的主要目的是在大气igw固有的时空尺度下，研究ABL中尺度风速和温度波动的空间结构和统计特征。为此，本项目主要开展了以下工作：1)中尺度风速和温度波动对大气边界层稳定条件下声信号传播参数影响的实验研究；2)在大气边界层稳定分层条件下，利用声层析成像与大气边界层垂直声探测相结合的方法测量大气边界层风速和温度的中尺度波动。为了解决这些问题，提出了一种基于不同声学层析成像方案（水平和垂直切片方案）和附加的ABL垂直声学探测方案相结合的新方法。这些声学遥感方法相互补充，可以重建ABL水平切片（300 x 300 qm）和垂直切片（地表以上300 m）内的风速和温度场。所获得的结果将填补我们在中尺度大气湍流特性方面的知识空白，并将有助于在大气环流和空气污染输送模式中参数化稳定ABL。