Collaborative Experiments of Convection and Gravity Waves

对流与重力波的协同实验

基本信息

批准号：
11694075
负责人：
TSUDA Toshitaka
金额：
$ 13.18万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11694075/
关键词：
gravity wave intra-seasonal oscillation radiosonde cumulus convection airglow MF radar equatorial waves vertical wavenumber spectra 赤道域成層圏中間圏熱帯大気レーダー CCDイメージャー

项目摘要

1. Balloon Observation of the troposphere and the stratosphereBy using daily radiosonde soundings from 1993 to 1996 in the equatorial Kalimantan, we have investigated long-term variability of atmospheric gravity waves and found their seasonal variation in the troposphere and a modulation by the Quasi-Biennial Oscillation in the stratosphere.We have conducted an observational campaign to launch radiosondes 4 times daily at three sites in each of Java, Sumatra, and Kalimantan Islands from November to December, 2000. Gravity waves were identified in the stratosphere, and their latitudinal dependence was revealed. Vertical wavenumber spectra showed tails with a -3 exponent down to the vertical wave length of 200m. Conventional theories have explained this feature in terms of saturation of gravity waves. Interestingly, however, it was shown that no saturation was seen in the observed lower stratosphere.2. Observation of gravity waves with all-sky imagersAn all-sky imager was installed in the suburb of Bandung, Indonesia to observe gravity waves projected onto OH airglow. We have successfully observed gravity waves at altitudes around 90km and studied horizontal structure and propagation. It was found that their propagation was mostly southward. The observation will be continued and is expected to provide data to reveal seasonal and year-to-year variability of the gravity waves.3. Observation of the mesosphere and lower thermosphere (MLT) by MF and meteor radarsA new antenna was added to the MF radar in Kalimantan in order to make it capable of measuring the momentum flux associated with waves in the MLT region. With the MF radar and a meteor radar in Java, long-term variation of gravity waves and long-period planetary-scale waves were investigated. Activities of gravity and Kelvin waves were found to be weak throughout two years from 1996. It was also found that waves with 30- to 60-day periods correlate well with tropospheric intra-seasonal oscillation.

1. 对流层和平流层气球观测通过使用1993年至1996年赤道加里曼丹岛的每日无线电探空仪探测，我们研究了大气重力波的长期变化，发现了对流层的季节变化和准两年期的调制平流层的振荡。我们开展了一项观测活动，每天在爪哇岛、 2000 年 11 月至 12 月，苏门答腊岛和加里曼丹群岛。在平流层中发现了重力波，并揭示了它们的纬度依赖性。垂直波数谱显示在垂直波长 200m 处有 -3 指数的尾部。传统理论用重力波的饱和度来解释这一特征。然而有趣的是，在观测到的平流层低层中并没有看到饱和现象。2．用全天空成像仪观测重力波在印度尼西亚万隆郊区安装了全天空成像仪来观测投射到 OH 气辉上的重力波。我们成功观测了90公里左右高度的重力波，并研究了水平结构和传播。结果发现，它们的传播大部分是向南进行的。观测将继续进行，预计将提供揭示重力波季节性和逐年变化的数据。3．通过中频和流星雷达观测中层和低层热层 (MLT) 加里曼丹的中频雷达增加了一个新天线，以便能够测量与 MLT 区域波浪相关的动量通量。利用爪哇的中频雷达和流星雷达，研究了重力波和长周期行星尺度波的长期变化。从1996年开始的两年里，重力波和开尔文波的活动都很弱。还发现周期为30到60天的波浪与对流层季节内振荡有很好的相关性。