热层大气夜间温度增强及其受八小时潮汐影响研究

发布时间：2018-04-13 19:29

本文选题：热层 + 夜间密度增强　；参考：《中国科学技术大学》2016年博士论文

【摘要】：热层大气温度在无太阳辐射加热的夜间出现升高的现象称为热层大气的夜间温度增强,而且类似的夜间增强也在热层大气密度中被观测到。由于热层密度夜间增强反映了温度夜间增强,本文统称热层温度和密度的夜间增强为热层大气夜间增强现象。自上世纪70年代以来,通过卫星和地基的观测,热层温度(密度)夜间增强现象被发现并得以研究。以往研究表明,热层大气的夜间增强一般发生在地方时0点至4点之间的赤道地区,其特征幅度在40K至150K之间。在本论文中,我们进一步深入研究了中高纬度地区的热层大气夜间增强现象,包括全球热层大气夜间增强现象随季节和纬度变化特性等,并探索了低层大气八小时迁移潮汐波的上传特性以及其对热层大气夜间温度／密度增强的影响。以下为本论文的主要结果：1.首先,通过分析美国磨石山Millstone Hill观测站(42.5°N,71.5°W)的非相干散射雷达以及法布里珀罗气辉干涉仪观测数据,研究了2011年8月1日至11日以及2012年1月12日至23日期间中纬度夜间的离子和中性气体温度变化情况。研究结果表明：在冬季夜间,离子和中性气体温度的夜间变化中存在后半夜增温现象,其发生在凌晨3-4点,且增温幅度为30-90 K。而在夏季,只有中性气体出现后半夜增温,而离子温度没有明显的夜间增温现象。我们的研究表明,中高纬地区热层中性气体后半夜增温由中低纬地区夜间增温现象向较高纬扩展导致。2.其次,利用2002年至2009年期间CHAMP卫星的热层大气密度数据,研究了不同季节以及不同太阳活动条件下的热层大气夜间密度随纬度和地方时的变化情况。结果表明,作为夜间温度增强现象在热层大气密度中的反映,夜间密度增强现象在各个季节以及不同太阳活动条件下都有发生,且其发生特征包括时间和强度等显著地随季节以及太阳活动的改变而改变。在太阳活动低年的条件下,赤道地区夜间密度增强现象的峰值时间在凌晨1点附近,而在太阳活动高年,赤道地区夜间密度增强现象峰值时间要早1至2个小时。此外,统计结果还表明,夜间密度增强现象表现出由赤道地区向南半球扩展趋势,且在太阳活动低年的条件下更加明显。3.再者,基于美国国家大气研究中心电离层热层电动力学耦合模式和加拿大中间层大气扩展模式,利用数值模拟的方法,研究热层大气温度(密度)夜间增强现象的形成机制。为了分析不同低层大气潮汐波对热层大气夜间热层大气温度(密度)夜间增强现象的贡献,我们研究在不同潮汐组合作为电离层热层电动力学耦合模式底边界条件下的热层大气温度、密度夜间的变化特性。模拟结果表明,周日、半日以及八小时潮汐的相互作用是形成热层大气夜间增强的主要原因,且低层大气的八小时潮汐显著地影响着热层大气夜间增强的纬度分布。此外,我们进一步揭示了热层大气八小时潮汐分量的来源,并得出热层大气的八小时潮汐受多种影响,包括：昼夜太阳辐射加热变化产生的谐波震荡,低层大气上传的八小时潮汐分量,以及半日潮汐与背景大气非线性相互作用结果。4.最后,为了揭示热层大气夜间增强的季节变化,我们通过数值模拟的方法,研究了八小时潮汐向上传播并影响热层大气的季节变化特性。我们发现：1)背景纬向风以及径向风可以显著的影响八小时潮汐的向上传播过程；2)低层大气的八小时潮汐不仅影响着热层大气八小时潮汐分量的幅度和纬度分布,同时也影响背景风对八小时潮汐上传过程：3)背景平均温度和温度梯度的半球差异同样影响着八小时潮汐的上传过程。
[Abstract]:Atmospheric temperature in solar radiation heating at elevated temperature at night phenomenon called enhancing the thermosphere, and similar enhancement in night thermosphere density was observed. Due to thermal layer density enhancement reflects the night temperature at night is enhanced, the paper referred to the hot layer temperature and density enhancement for the night the thermospheric night enhancement phenomenon. Since the last century since 70s, through the observation satellite and ground temperature, thermal layer (density) night enhancement phenomenon was found and studied. Previous studies have shown that atmospheric night enhancement generally occurs in the place of 0 points to 4 points between the equatorial regions, the characteristics of the range between 40K to 150K. In this thesis, we further study the heat in the atmosphere in high latitude regions night enhancement phenomena, including the global thermospheric night enhancement with season and latitude variation Etc., and explored the characteristics of tidal wave upload of the lower atmosphere eight migrated and the atmospheric temperature at night / density enhancement effect. The following is the main results of this thesis: 1. first of all, through the analysis of the Moshishan Millstone Hill Observatory (42.5 ~ N, 71.5 ~ W) of the non scattering radar Perot airglow interferometer and data coherence, during the study period from August 1, 2011 to 11 and January 12, 2012 to 23 days in the ion latitude nighttime and neutral gas temperature changes. The results show that: in the winter night after midnight, there warming ions and neutral gas temperature changes in the night, it happened at 3-4 a.m., and the warming rate is 30-90 K. in the summer, only the neutral gas appears after midnight warming, while the ion temperature has no obvious Nighttime Warming. Our study shows that in high latitudes in the thermosphere Gas after midnight warming by middle and low latitudes in nighttime warming phenomenon to a high latitude extension leads to.2. second, using the data from 2002 to 2009 during the CHAMP satellite thermospheric density, were studied in different seasons and different solar activities under the conditions of the thermospheric density changes with night latitude and local time. The results showed that as the night temperature enhancement phenomenon reflected in the density of heat in the atmosphere, the night density enhancement phenomenon has occurred in all seasons and different solar activity conditions, and its features include the time and intensity of significant seasonal and solar activity changes. In the condition of low solar activity under the equator at night the phenomenon of enhanced density peak time in the vicinity of 1 in the morning, and in the high solar activity, the equatorial region density enhancement peak time at night to early 1 to 2 hours. In addition, the The results also show that the night density enhancement phenomenon showed by the equatorial region of the southern hemisphere and the expansion trend, in the condition of low solar activity years is more obvious in the case of.3. in the middle of the National Center for Atmospheric Research of ionospheric electrodynamic coupling mode and Canada thermal layer layer gas expansion model based on the method of numerical simulation is used to study the thermal atmosphere the temperature (density) at night. In order to enhance the formation mechanism of the phenomenon of different atmospheric tidal wave of atmospheric nighttime atmospheric temperature (density) night enhancement contribution, we study in different tidal combination as atmospheric temperature thermal coupling model of bottom layer ionospheric electrodynamics boundary conditions, the density characteristics at night the simulation results show that, on Sunday, eight hours and the interaction of semidiurnal tides is mainly due to the formation of thermospheric nighttime enhancement, and low layer The eight hour tidal gas significantly affects the latitude distribution of atmospheric nighttime enhancement. In addition, we further reveal the source of atmospheric tidal component for eight hours, and the atmospheric eight hour tide is affected by many factors, including: the harmonic oscillation generates circadian variation of solar radiation heating, the lower atmosphere upload the eight hour tidal component, as well as the semidiurnal tide and background atmospheric nonlinear interaction results in.4. at last, in order to reveal the seasonal variation of atmospheric nighttime enhancement, we adopted the method of numerical simulation, studied eight hours to spread and influence on tidal seasonal variation characteristics of thermospheric. We found that: 1) the background zonal wind and radial the wind can significantly affect the eight hour tidal upward propagation process; 2) the lower atmosphere eight hours tide not only affects the atmospheric eight hour tidal component amplitude and latitude The degree distribution also affects the background wind to the eight hour tidal transmission process: 3) the hemispherical difference between the background mean temperature and the temperature gradient also affects the eight hour tidal transmission process.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P351

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