Importance of capturing heliospheric variability for studies of thermospheric vertical winds
Importance of capturing heliospheric variability for studies of thermospheric vertical winds
复制标题
捕获日光层变化对于热层垂直风研究的重要性
DOI：
10.1029/2012ja017596
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发表时间：
2012
影响因子：
--
通讯作者：
M. Moldwin
中科院分区：
文献类型：
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作者：
Erdal Yiğit;A. Ridley;M. Moldwin
[1]利用全球电离层热层模式和实时观测的日球输入资料，研究了热层中性垂直风的大小和变率。为了确定行星际磁场（IMF）和太阳风密度的变化对中性风变化的作用，对日光层输入数据进行了平滑处理。模拟了无平滑、5分钟平滑和12分钟平滑的情况下，IMF平滑、太阳风和密度平滑对垂直风场的影响。各种垂直风加速度的条款，如非静水加速度，量化。垂直风和离子流的变异性的极赤平投影进行比较，突出现有的相关性。总的来说，平滑，也就是说，IMF和太阳风参数的变化越少，越弱的幅度和变化的热层垂直风。较弱的IMF可变性导致离子流的较小可变性，这反过来又对焦耳加热的可变性和幅度产生负面影响。垂直风加速度的小尺度时间变化，从而垂直风的变化，主要是由非流体静力学项，主要是由焦耳加热的时间变化控制，这反过来又与离子流的变化，是由国际货币基金组织在高纬度热层的形状。垂直风数据的小波分析表明，当模型使用高分辨率实时IMF和太阳风数据运行时，周期为5分钟和10分钟的重力波更为突出。更好地捕捉IMF和太阳风参数的时间变化是至关重要的热层垂直风的变化和大小建模。
[1] Using the Global Ionosphere Thermosphere Model with observed real-time heliospheric input data, the magnitude and variability of thermospheric neutral vertical winds are investigated. In order to determine the role of variability in the Interplanetary Magnetic Field (IMF) and solar wind density on the neutral wind variability, the heliospheric input data are smoothed. The effects of smoothing the IMF and solar wind and density on the vertical winds are simulated for the cases of no smoothing, 5-minute, and 12-minute smoothing. Various vertical wind acceleration terms, such as the nonhydrostatic acceleration, are quantified. Polar stereographic projections of the variabilities of vertical wind and ion flows are compared to highlight existing correlations. Overall, the smoother, that is, the less variable the IMF and solar wind parameters are, the weaker are the magnitude and the variability of the thermospheric vertical winds. Weaker IMF variability leads to smaller variability in ion flows, which in turn negatively impacts the variability and the magnitude of Joule heating. Small-scale temporal variation of the vertical wind acceleration, and thus the variability of the vertical wind, is dominated by the nonhydrostatic term that is controlled primarily by the temporal variation of the Joule heating, which in turn is related to ion flow variations that are shaped by the IMF in the high-latitude thermosphere. Wavelet analysis of the vertical wind data shows that gravity waves of � 5 and � 10-minute periods are more prominent when the model is run with high-resolution real-time IMF and solar wind data. Better capturing of the temporal variation of the IMF and solar wind parameters is crucial for modeling the variability and magnitude of thermospheric vertical winds.