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
• 负责人: TAJIMA Toshihiko
• 金额: $ 2.11万
• 依托单位: TOYAMA NATIONAL COLLEGE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640442/
• 关键词: Rotating annulus fluid experiments; Large-scale circulation of the atmosphere; Troposphere; Stratosphere; Rossby wave; Hadley flow; Beta-effect; Ozone layer; 臨界層; PIV; ロスビー流

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 5 cm stratified by heating the water surface. In this research project, Grant-IN-Aid far Scientific Research, we have gotten the following two experimental results : 【encircled 1】The vorticities of barodinic waves produced in the tower fluid layer penetrate into the stratified upper layer decaying exponentially with height according to the quasi-geostrophic potential vorticity equation in the atmospheric dynamics ; 【encircled 2】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 the result 【encircled 1】to the real atmosphere, in particular, that the ozone layer 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 result 【encircled 1】 was described in the paper that was accepted for the publication in Experiments in Fluids. The result 【encircled 1】 has been summarized in the paper submitted to Journal of Atmospheric Sciences.

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，在5cm以上的上层通过加热水面使之分层。在“科学研究资助”项目中，我们得到了以下两个实验结果：（1）根据大气动力学中的准地转位涡方程，在塔状流体层中产生的正压波的涡度穿透到层结上层，随高度呈指数衰减;如果分层层足够深，则在斜压低层中出现稳定的轴对称流或波流需要强分层（垂直温度梯度）。将[圈1]的结果应用到真实的大气中，特别是臭氧层吸收紫外线，使大气升温，形成平流层，发现对中纬度大尺度对流层风是必不可少的。结果[圈1]中所描述的文件被接受的出版物在实验流体。结果[圈出1]已在提交给《大气科学杂志》的论文中进行了总结。

项目成果

Toshihiko Tajima, Toshiro Nakamura: "Experiments to study baroclinie waves penetrating into a stratified layer by a quasi-geostrophic potential vorticity equation"Experiments in Fluids. (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。

Toshihiko Tajima: "Experiments to study baroclinic waves penetrating into a stratified layer by a quasi-geostrophic potential vorticity equation"Experiments in Fluids. (発表予定).

Toshihiko Tajima：“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（待提交）。

T.Tajima, T.Nakamura: "Experiments to study baroclinic waves penetrating into a stratified layer by a quasi-geostrophic potential vorticity equation"Experiments in Fluids. (2003)

T.Tajima、T.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。