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Lidar observations and modeling studies of Antarctic temperature tides at McMurdo & establishment of temperature climatology with calibrated Fe Boltzmann and Na doppler lidars.

机译：麦克默多（McMurdo）的南极温度潮汐的激光雷达观测和建模研究，以及用校准的Fe Boltzmann和Na多普勒激光雷达建立的温度气候学。

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摘要

McMurdo lidar campaign provides invaluable data for studies of the polar middle and upper atmosphere. The science topics to be addressed in this dissertation are the temperature tides (30--110 km) and temperature climatology (0--110 km). Tides are important to the dynamic and chemical processes in the middle and upper atmosphere. Tides, for examples, can obtain large amplitudes in the middle and upper atmosphere, where they modulate ionospheric variability via the E-region dynamo effect, enhance vertical atmosphere coupling and cause instabilities by inducing significant temperature gradients and wind shears. However, observations of tides in the Antarctic region are rare, especially for temperature tides. In this dissertation, we present lidar measurements of winter tides from 30 to 110 km at McMurdo (77.8°S, 166.7°E). The observed diurnal and semidiurnal tides indicate small amplitudes (less than 3 K) below 100 km, but above 100 km, we observed fast growth of tidal amplitudes to at least 15 K near 110 km, exceeding that of the freely propagating tides originating from the lower atmosphere. Such fast growth of tidal amplitude raises questions regarding the identification of sources of the tides above 100 km and how these sources are related to geomagnetic activities or other factors.;We utilized the Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics (CTIPe) model to further investigate the questions raised. Simulations with the CTIPe model reproduce the lidar observations and exhibit a concentric ring structures of diurnal amplitudes encircling the south geomagnetic pole and overlapping the auroral zone. These findings point to a magnetospheric source origin. Mechanistic studies using CTIPe show that the adiabatic cooling/heating associated with Hall ion drag is the dominant source of this feature, while Joule heating is a minor contributor due to the counteraction by Joule-heating-induced adiabatic cooling. The sum of total dynamical effects and Joule heating explains ~80% of the diurnal amplitudes. The auroral particle heating, lower atmosphere tides, and direct solar heating have minor contributions, according to the CTIPe model.;In the polar region, temperature controls numerous geophysical phenomena and is also a key variable in climate change studies. We derived the temperature climatology from the ground to 110 km at McMurdo based on the 4 years of lidar and radiosonde observations, and applied the backward differtiation method to fill in the data gaps. The climatology is compared with model outputs and satellite measurements. The latitudinal dependences of stratopause and mesopause temperature were found between different Antarctica stations. The McMurdo lidar campaign also demonstrated the potential to push the temperature climatology lid altitude to 120 km during winter, where measurements are extremely rare.;Finally, we utilize the forward model method to assess how PMT non-linear response and laser pulse spectrum affect the temperature and radial wind measurements of a 3-frequency Na Doppler lidar. As the polar region from 100 to 200 km is the least understood and most sparsely observed region, the tidal study presented here will help improve the current understanding of how the wave coupling between the ionosphere plasma and the neutral thermosphere. Also, the establishments of the temperature climatology and temperature calibration not only reveal the thermal structure at McMurdo, but also provide references for the future studies. The calibrated temperature data will serve as the baseline for comparison with measurements made decades in the future, and the calibration methods we developed will be a guideline for the lidar field.
机译：麦克默多激光雷达运动为极地中高层大气的研究提供了宝贵的数据。本论文要解决的科学问题是温度潮（30--110 km）和温度气候学（0--110 km）。潮汐对中高层大气的动态和化学过程很重要。例如，潮汐可以在中层和高层大气中获得较大的振幅，在那里它们通过E区域的发电机效应调节电离层的变化性，增强垂直大气的耦合，并通过引起明显的温度梯度和风切变而引起不稳定。但是，对南极地区的潮汐观测很少，特别是对于温度潮汐。在本文中，我们介绍了在麦克默多（77.8°S，166.7°E）从30到110 km的冬季潮汐的激光雷达测量。观测到的日，半日潮汐表明，低于100 km的振幅较小（小于3 K），但高于100 km时，我们观察到110 km附近的潮汐振幅快速增长至至少15 K，超过了源自该区域的自由传播的潮汐。低层大气。如此快速的潮汐增幅引发了有关识别100 km以上潮汐源以及这些源与地磁活动或其他因素如何相关的问题。;我们利用耦合热层电离层等离子体电动力学（CTIPe）模型进一步研究了这些问题提高。用CTIPe模型进行的模拟重现了激光雷达的观测结果，并显示了一个围绕南地磁极并与极光带重叠的日振幅的同心环结构。这些发现指出了磁层来源的起源。使用CTIPe进行的机理研究表明，与霍尔离子阻力相关的绝热冷却/加热是此功能的主要来源，而焦耳加热的贡献较小，这归因于焦耳加热引起的绝热冷却的反作用。总动力效应和焦耳热的总和解释了日振幅的约80％。根据CTIPe模型，极光粒子加热，低潮汐和直接太阳加热的贡献很小。在极地地区，温度控制着许多地球物理现象，也是气候变化研究中的关键变量。基于4年的激光雷达和探空仪观测，我们得出了麦克默多从地面到110 km的温度气候学，并应用了后向差分法来填补数据空白。将气候与模型输出和卫星测量结果进行比较。在不同的南极站之间发现了层间断层和中层间断层温度的纬度相关性。 McMurdo激光雷达运动还证明了在冬季极少进行测量的冬季将气候气候盖高度推升至120 km的潜力。最后，我们利用正向模型方法评估PMT非线性响应和激光脉冲频谱如何影响雷达的温度。 3频Na多普勒激光雷达的温度和径向风测量。由于从100到200 km的极地地区是人们了解得最少，最稀疏的地区，因此在此进行的潮汐研究将有助于增进当前对电离层等离子体与中性热层之间波耦合的了解。此外，温度气候学和温度校准的建立不仅揭示了麦克默多的热结构，而且还为将来的研究提供了参考。校准后的温度数据将作为基准，与未来数十年进行的测量进行比较，我们开发的校准方法将成为激光雷达领域的指南。

著录项

  • 作者

    Fong, Weichun.;

  • 作者单位

    University of Colorado at Boulder.;

  • 授予单位 University of Colorado at Boulder.;
  • 学科 Atmospheric sciences.;Optics.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 183 p.
  • 总页数 183
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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