Rotating annulus experiments to simulate the air motion in the stratified layer
旋转环空实验模拟分层层中的空气运动
基本信息
- 批准号:15540425
- 负责人:
- 金额:$ 2.05万
- 依托单位:
- 依托单位国家:日本
- 项目类别:Grant-in-Aid for Scientific Research (C)
- 财政年份:2003
- 资助国家:日本
- 起止时间:2003 至 2004
- 项目状态:已结题
- 来源:
- 关键词:
项目摘要
The air motions in the stratosphere have been so far studied theoretically and by numerical simulations. Laboratory simulations are, however, also useful to investigate their basic dynamical structures. The purpose of this project is to conduct experiments on a rotating fluid annulus to study the upward propagations of the baroclinic flows into the upper stratified layer and to produce the tightly closed vortex such as the polar one in the stratosphere. Using the annulus whose water depth is 13〜14 cm, we have succeeded in producing the baroclinic flows in the lower layer imposed the radial temperature difference below 3 cm and making the upper layer above 4 cm stratified by heating the water surface. In the former half of this research project which followed the previous Grant-in-Aid for Scientific Research (2001〜2002), we had confirmed the following two experimental results for the cases without the introduction of the beta-effect. (1)Upward fluid motions make the baroclinic flows per … More meate into the upper layer. The stable stratification, however, suppresses the upward motions so that the zonal fluid velocities decrease exponentially with height, which was shown to follow the quasi-geostrophic potential vorticity equation in the atmospheric dynamics. (2)In fact, their maximum appears at the top level of the baroclinic lower layer and the sign of the radial temperature gradient changes there according to the thermal wind relation: Namely it is warmer on the inner side of the annulus in the upper layer. This temperature profile is reflected in a meridional fluid circulation mixing both layers, which corresponds to real atmospheric phenomena. If the stratified layer is sufficiently deep, strong stratification (vertical temperature gradient) is necessary for steady axisymmetric or wave flows to emerge in the baroclinic lower layer. Applying this result to the real atmosphere, the ozone layer that absorbs the ultraviolet light and warm up the air to make the stratosphere is found essential for the mid-latitude large-scale tropospheric winds. The papers to describe results (1) and (2) was and will be published in Experiments in Fluids (2003, 2005).In atmospheric dynamics, it is well known that the beta-effect, namely the variation of Coriolis force with latitude causes mid-latitude large-scale tropospheric waves such as the westerlies to propagate non-exponentially-decreasingly vertically and induces predominant wave motions in the stratosphere. In the latter half of this research project, we demonstrate rotating fluid annulus experiments setting a conical bottom in a tank to create an equivalent beta-effect. Three dear evidences of the beta-effect were observed in wavenumber-2 flow: the wave flow propagated vertically, its critical level rose, and its drift velocity reduced. Then the quasi-geostrophic potential vorticity equation succeeded in describing this phenomenon below a height a little lower than the critical level, but failed near that level. This result was summarized in the paper submitted to Experiments in Fluids (2005). Less
平流层中的空气运动迄今为止已经从理论上和数值模拟方面进行了研究。然而,实验室模拟也有助于研究它们的基本动力学结构。本项目的目的是在旋转流体环上进行实验,研究斜压气流向上传播到上层层结层中,并在平流层中产生类似极涡的紧闭涡。利用水深为13 ~ 14 cm的环空,在3cm以下的径向温差作用下,成功地在下层产生斜压流,并通过加热水面使4cm以上的上层分层。在本研究项目的前半部分,即上一次科学研究补助金(2001年至2002年)之后,我们已经证实了以下两个实验结果的情况下,没有引入β效应。(1)向上的流体运动使斜压气流, ...更多信息 进入上层。稳定层结抑制了上升运动,使得纬向流体速度随高度呈指数下降,这符合大气动力学中准地转位涡方程。(2)In实际上,它们的极大值出现在斜压低层的顶层,并且那里的径向温度梯度的符号根据热成风关系发生变化,即在上层环的内侧较暖。这种温度廓线反映在一个混合两层的纬向流体环流中,这与真实的大气现象相对应。如果层结层足够深,则在斜压低层中出现稳定的轴对称流或波流需要强的层结(垂直温度梯度)。将这一结果应用到真实的大气中,发现吸收紫外线并使空气升温以形成平流层的臭氧层是中纬度大尺度对流层风的必要条件。描述结果(1)和(2)的论文已经和将要发表在Experiments in Fluids(2003,2005)上。在大气动力学中,众所周知,β效应,即科氏力随纬度的变化,会导致中纬度大尺度对流层波(如西风带)以非指数衰减的方式垂直传播,并在平流层中诱发主导波动。在本研究计划的后半部分,我们展示了旋转流体环空实验,在水箱中设置一个圆锥形底部,以产生等效的β效应。在波数为2的流动中,观察到了β效应的三个明显证据:波流垂直传播,其临界水位上升,其漂移速度降低。准地转位涡方程在略低于临界水平的高度以下能成功地描述这种现象,但在接近临界水平时却不能。这一结果总结在提交给Experiments in Fluids(2005)的论文中。少
项目成果
期刊论文数量(16)
专著数量(0)
科研奖励数量(0)
会议论文数量(0)
专利数量(0)
Experiments to study interactions between baroclinic lower flows and a stably stratified upper layer
研究斜压下层流与稳定分层上层之间相互作用的实验
- DOI:
- 发表时间:2005
- 期刊:
- 影响因子:0
- 作者:T.Tajima;T.Nakamura;K.Kawahira
- 通讯作者:K.Kawahira
Toshihiko Tajima, Toshiro Nakamura: "Expeliments to study baroclinic waves penetrating into a stratified layer by a quasi-geostrophic potential vorticity equation"Experiments in Fluids. 34巻. 744-747 (2003)
Toshihiko Tajima、Toshiro Nakamura:“通过准地转位涡方程研究斜压波穿透层状层的实验”流体实验第 34 卷。744-747 (2003)
- DOI:
- 发表时间:
- 期刊:
- 影响因子:0
- 作者:
- 通讯作者:
Experiments to study the Beta-effect in atmospheric dynamics
研究大气动力学中贝塔效应的实验
- DOI:
- 发表时间:2005
- 期刊:
- 影响因子:2.4
- 作者:T.Tajima;T.Nakamura
- 通讯作者:T.Nakamura
Experiments to study baroclinic waves penetrating into a stratified layer by a quasi-geostrophic potential vorticity equation
用准地转位涡方程研究斜压波穿透层状层的实验
- DOI:
- 发表时间:2003
- 期刊:
- 影响因子:0
- 作者:T.Tajima;T.Nakamura
- 通讯作者:T.Nakamura
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TAJIMA Toshihiko其他文献
TAJIMA Toshihiko的其他文献
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{{ truncateString('TAJIMA Toshihiko', 18)}}的其他基金
Rotating annulus experiments to study the beta-effect in atmospheric dynamics
旋转环空实验研究大气动力学中的贝塔效应
- 批准号:
18540435 - 财政年份:2006
- 资助金额:
$ 2.05万 - 项目类别:
Grant-in-Aid for Scientific Research (C)
Rotating annulus experiments to simulate the air motion in the stratified layer
旋转环空实验模拟分层层中的空气运动
- 批准号:
13640442 - 财政年份:2001
- 资助金额:
$ 2.05万 - 项目类别:
Grant-in-Aid for Scientific Research (C)
Chaotic analyses of 3D Lagrangian motions in the rotating annulus experiments.
旋转环实验中 3D 拉格朗日运动的混沌分析。
- 批准号:
11640435 - 财政年份:1999
- 资助金额:
$ 2.05万 - 项目类别:
Grant-in-Aid for Scientific Research (C)
Laboratory simulations of atmospheric dynamics in the rotating fluid annulus experiments.
旋转流体环空实验中大气动力学的实验室模拟。
- 批准号:
07640582 - 财政年份:1995
- 资助金额:
$ 2.05万 - 项目类别:
Grant-in-Aid for Scientific Research (C)
Multiple liquid crystal techniques of visualization for 3-D measurements in the rotating annulus experiments
旋转环实验中 3D 测量的多种液晶可视化技术
- 批准号:
04559012 - 财政年份:1992
- 资助金额:
$ 2.05万 - 项目类别:
Grant-in-Aid for Developmental Scientific Research (B)