Research on the coupling process between the lower thermosphere and the mesosphere in the polar region by using radar observations and model predictions

利用雷达观测和模型预测研究极地低层热层与中间层的耦合过程

基本信息

批准号：
16340146
负责人：
NOZAWA Satonori
金额：
$ 10.61万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2007
项目状态：
已结题

项目摘要

The lower thermosphere at high latitudes is a unique region in the earth's atmosphere, because the atmosphere there couples with the middle/lower atmosphere as well as the ionosphere and magnetosphere. The lower thermosphere is significantly influenced by atmospheric waves propagating below as well as by their dissipation. Furthermore, during geomagnetically disturbed periods, the lower thermosphere interacts with the ionosphere and magnetosphere through several physical processes. These coupling processes with upper or lower regions are, however, not yet fully understood. To understand such a coupling process more deeply, we have made studies by using EISCAT radars, other radars and model simulations. Major results are as follows. (1) We investigated the importance of the ion drag by using EISCAT radar(KST and ESR)data obtained for 11-19 November 2003. We showed the importance of the ion drag and also suggested the pressure gradient could play another important role. (2) We investigated the ion drag contribution to the diurnal tidal amplitude by analyzing the data obtained for 1-7 July 1999 by ESR. We presented that sixty percent of the diurnal tidal amplitude arose from the ion drag acceleration. (3)We conducted the DELTA rocket campaign for December 2004 to understand the effect of the anal activity to the lower thermospheric wind dynamics. By analyzing FISCAT data for 74 hours hi total, we showed the day-to-day variability of the sermidiunal tide. (4)We showed that the magnitude and the dissipation height of the turbulent and electromagnetic energy poured from the upper and lower regions seem to be strongly dependent on the neutral wind particularly below〜10 km based on ESR data Also, we derived the height distributions of the thermospheric heating rate at the F region height on 9 March 1999 in association with electromagnetic energy inputs into the dayside polar cap/cusp region.

高纬度的较低热层是地球大气中的一个独特区域，因为那里的大气层与中/下大气以及电离层和磁层。较低的热层受到下面传播及其耗散的大气波的显着影响。此外，在地磁干扰时期，下热层通过多个物理过程与电离层和磁层相互作用。但是，这些与上或下区域的耦合过程尚未完全理解。为了更深入地了解这种耦合过程，我们通过使用EISCAT雷达，其他雷达和模型模拟进行了研究。主要结果如下。（1）我们通过使用2003年11月11日获得的Eiscat雷达（KST和ESR）数据调查了离子阻力的重要性。我们展示了离子阻力的重要性，还表明压力梯度可以发挥另一个重要作用。（2）我们通过分析ESR 1999年7月1日获得的数据来研究对不同潮汐放大器的离子阻力贡献。我们提出，不同的潮汐放大器中有60％来自离子阻力加速度。（3）我们在2004年12月进行了三角洲火箭运动，以了解肛门活动对下热层风力动力学的影响。通过分析了74小时HI的分析数据，我们显示了Sermidiunal Tide的日常变异性。（4）我们表明，根据ESR数据，从上和下部区域倒入的湍流和电磁能的大小和耗散高度似乎很大程度上取决于中性风，尤其是低于10 km的中性风，我们得出了1999年3月9日在9月9日与电子能量输入的F区域高度的热层加热速率的高度分布到1日999的高度。