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Latitudinal (apex-height) variations of ion drifts in the ionosphere at low- and mid-latitudes.

机译:在低纬度和中纬度,电离层中离子漂移的纬度(顶点高度)变化。

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摘要

In this study we focus on the dynamics of the ion drift velocities at low and middle latitudes. We describe how these ion drifts vary in latitude for different longitudes, seasons and specific local times during quiet times.;During quiet times we use data from the ROCSAT-1 satellite to describe the latitude dependence of three main features of the meridional ion drifts; the large-scale upward drifts during daytime, a so-called prereversal enhancement near dusk, and a downward sunrise enhancement. The longitude, latitude and seasonal dependences in these features are influenced by the alignment of the terminators with the magnetic meridian, the flux tube integrated conductivities and the action of diurnal and semidiurnal tides in the lower ionosphere.;We also obtained a description of the zonal ion drifts during quiet times. These drifts show latitude, longitude and seasonal variations, driven by the combined effects of the E-region and F-region winds. Changes in the wind and the F-region Pedersen conductance are responsible for latitude, longitude and seasonal changes in the net superrotation of the ionosphere.;Additionally, we describe storm time perturbations in the ion drifts at the magnetic equator. These perturbations are mainly produced by undershielding and overshielding of the magnetospheric electric field during times when the Interplanetary Magnetic Field is changing. The role of the disturbance dynamo can also be seen in the perturbation drifts at the equator.;Using measurements from the DMSP-F13, F-15 and ROCSAT-1 satellites we are able to describe for the first time, storm-time drift perturbations at the equator observed simultaneously at different local times.
机译:在这项研究中,我们关注中低纬度的离子漂移速度的动力学。我们描述了这些离子漂移在静默时间内对于不同的经度,季节和特定本地时间在纬度上的变化。在静默期间,我们使用来自ROCSAT-1卫星的数据来描述子午离子漂移的三个主要特征的纬度依赖性;白天大范围的向上漂移,黄昏附近的所谓逆转增强和朝下的日出增强。这些特征中的经度,纬度和季节依赖性受以下因素影响:终止子与磁子午线的对准,通量管的综合电导率以及电离层下部日,半日潮汐的作用。离子在安静的时候漂移。这些漂移显示出纬度,经度和季节变化,这是由E区域和F区域风的共同作用驱动的。风的变化和F区的Pedersen电导是电离层净超旋转的纬度,经度和季节变化的原因。此外,我们描述了磁赤道处离子漂移中的风暴时间扰动。这些扰动主要是由于在行星际磁场变化时磁层电场的欠屏蔽和过屏蔽引起的。扰动发电机的作用还可以在赤道的扰动漂移中看到。使用DMSP-F13,F-15和ROCSAT-1卫星的测量值,我们可以首次描述暴风雨时间的漂移扰动在不同的当地时间同时观测到的赤道

著录项

  • 作者单位

    The University of Texas at Dallas.;

  • 授予单位 The University of Texas at Dallas.;
  • 学科 Aeronomy.;Atmospheric Sciences.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 153 p.
  • 总页数 153
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 康复医学;
  • 关键词

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