Research on the atmospheric dynamics in the polar raesosphere/thermosphere

极地热层大气动力学研究

基本信息

批准号：
11640441
负责人：
NOZAWA Satonori
金额：
$ 2.18万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640441/
关键词：
lower Thermosphere Mesosphere Polar region neutral wind EISCAT radar MF radar Geomagnetically quiet perkid Total reflection height 中性風地磁気静隠時

项目摘要

We have studied the atmospheric dynamics in the polar mesosphere/lower thermosphere. The atmospheric dynamics in the lower thermosphere and upper mesosphere is strongly controlled by atmospheric waves such as gravity, tidal, and planetary waves which mainly propagate upward from below. To understand the lower thermospheric wind dynamics more fully, therefore, in addition to examining the lower thermospheric wind variations, it is of vital importance to examine how these waves propagate and dissipate and what kind of role these waves play in the lower thermosphere. Seasonal and solar cycle variations of the lower thermospheric wind system were widely examined based on the European Incoherent Scatter (EISCAT) radar as well as NCAR Thermosphere-Ionosphere-Mesosphere-Electrodynamics general circulation model. It is found that, for example, a strong eastward mean wind (about 40 m/s) in summer maximizing at 101 km, and suggested that this feature in the altitude wind profile is produced by g … More ravity wave drag.We made comparison studies of three methods of the EISCAT UHF radar for furnishing E region neutral wind data. An EISCAT Special Program was conducted for 24 hours starting at 10 UT on July 14, 1997. Derived wind velocities by the three methods are compared, and fairly good agreement is found in terms of a relatively longer temporal variation (a few hours). The comparison of the derived velocities shows that the tristatic method is superior to the monostatic method in terms of an instantaneous measurement, while the monostatic method has an advantage on a tidal study. Regarding the meridional wind component, the filed-aligned method has significant advantages compared to the other methods concerning temporal data coverage, error, and height coverage.We also examined how we can use two radars such as the EISCAT UHF radar and ME radar for study of the coupling process of the mesosphere and lower thermosphere. Comparisons of winds are made in case studies as well as on a statistical basis. Based on the comparisons, we raise strong concerns regarding the use of summer wind data above 91 km obtained by ME radar located at high latitude under high solar activity conditions. The wind values during the winter and equinox observed by the 2 radars are complementary. Less

我们已经研究了极性层/下热层中的大气动力学。下部热层和上层上层中的大气动力学受到重力，潮汐和行星波等大气波的强烈控制，这些波浪主要从下方向上传播。因此，除了检查较低的热层风变化外，还要更充分地了解较低的热层风力动力学，对于研究这些波如何传播和消散以及这些波在较低热层中起何种作用至关重要。基于欧洲不连贯的散射（EISCAT）雷达以及NCAR热层 - 离子层 - 层 - 层 - 电动动力学通用循环模型，对下热层风系统的季节性和太阳周期变化进行了广泛检查。发现例如，夏季在101 km处最大化强烈的向东平均风（约40 m/s），并建议在高度风轮廓中产生此特征。从1997年7月14日开始，进行了24小时的EISCAT特殊计划。比较了三种方法的派生速度，并且根据相对较长的临时变化（几个小时），发现了相当良好的一致性。衍生速度的比较表明，在瞬时测量方面，Tristatic方法优于单恒定方法，而单音节方法在潮汐研究中具有优势。关于子午风组件，与有关临时数据覆盖，误差和高度覆盖范围的其他方法相比，归档的方法具有显着的优势。我们还研究了如何使用两个雷达，例如Eiscat UHF雷达和ME ME雷达来研究Mesosphere和Shoftosphere和下圈的耦合过程。在案例研究以及统计基础上进行风的比较。根据比较，我们对在高太阳活动条件下位于高纬度的ME雷达获得的夏季风数据提出了强烈的关注。冬季的风值和2个雷达观察到的春分是完整的。较少的