【作者】 王栋；

【导师】 谷升阳；

【作者基本信息】 武汉大学 ， 空间探测与信息处理技术， 2024， 硕士

【摘要】 气辉的时空分布受到大气重力波、潮汐波和行星波等各种大气动力学过程的调制,可以作为大气中发生的许多动力学过程的指标。本文利用多通道红外辐射计(Sounding of the Atmosphere using Broadband Emission Radiometry,简称SABER)观测的OH气辉数据,使用最小二乘拟合方法,计算OH气辉的垂直综合辐射率、辐射中心高度、峰值辐射率和峰值高度。研究了OH气辉辐射率和高度的半年度振荡(Semi-Annual Oscillation,简称SAO)、年度振荡(Annual Oscillation,简称AO)、准两年振荡(Quasi-Biennial Oscillation,简称QBO)和太阳周期变化,并分析其纬度依赖性。本文的主要研究结果如下:在低纬度地区,SAO占主导地位。在分点附近,OH气辉辐射率出现最大值(春分时大于秋分时),辐射高度出现最小值(春分时小于秋分时)。在中纬度地区,AO占主导地位,振幅的极值出现在年初附近。对于辐射率,北半球的AO振幅大于南半球对应纬度的振幅。对于辐射高度,南半球的AO振幅大于北半球对应纬度的振幅。在赤道,OH气辉辐射还受到赤道平流层背景风QBO的调制。在平流层纬向风处于东向(西向)风阶段时,气辉辐射率相对较大(小),辐射高度较低(高)。纬向风相位变化和气辉辐射的相位变化表现出一定相似性。通过计算得到,气辉辐射时间序列与纬向风时间序列相差三个月时,两者间相关系数最大。在更高纬度,气辉辐射受到QBO的调制较弱。此外,OH气辉辐射也受到太阳活动的调制。我们用10.7厘米太阳射电通量作为太阳活动的代表,分析了OH辐射与太阳活动的关系。我们的研究结果表明OH气辉辐射率中的太阳周期特征强于辐射高度中的太阳周期特征,并表现出明显的纬度依赖性。我们认为OH气辉中的太阳周期变化更多是由于化学而非动力学过程。在中间层顶区域,臭氧-氢的反应是生成OH气辉的主要反应,同时臭氧的生成需要原子氧。因此,OH气辉辐射率的变化将主要由原子氧的变化决定。基于动力学模式的带有热层和电离层扩展的全大气社区气候模型(Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere and ionosphere e Xtension,简称SD-WACCM-X)输出的原子氧浓度数据代表原子氧的垂直输运。结果表明,气辉辐射率增大和辐射高度降低都与原子氧垂直输运有关。与SABER观测到的温度数据计算出的周日迁移潮汐(DW1)振幅比较,赤道地区85 km高度处DW1振幅表现出SAO和QBO,最大振幅出现在春分附近。赤道地区OH气辉辐射和DW1振幅一样,都表现出SAO和QBO是由于垂直运动引起的原子氧的相应潮汐变化。更多还原

【Abstract】 The spatial and temporal distribution of airglow is modulated by various atmospheric dynamical processes such as atmospheric gravity waves,tidal waves and planetary waves,and can be used as an indicator of many dynamical processes occurring in the atmosphere.In this paper,we use the OH airglow data observed by Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)to calculate the vertically integrated emission rate,the centroid altitude,the peak emission rate and the peak height of the OH airglow using the least-squares fitting method.The semi-annual oscillation(SAO),annual oscillation(AO),quasi-biennial oscillation(QBO),and solar cycle variations of the OH airglow emission rate and altitude are investigated and their latitudinal dependence is analysed.The main results of this paper are as follows:At low latitudes,SAO dominates.Near the equinox,the OH airglow emission rate reaches its maximum value(greater at the spring equinox than at the autumnal equinox),and the emission height reaches its minimum value(smaller at the spring equinox than at the autumnal equinox).At mid-latitudes,the AO dominates,with extremes of amplitude occurring near the beginning of the year.For the emission rate,the AO amplitude in the northern hemisphere is larger than the amplitude at the corresponding latitude in the southern hemisphere.For the emission height,the AO amplitude in the southern hemisphere is larger than the amplitude at the corresponding latitude in the northern hemisphere.At the equator,the OH airglow emission is also modulated by the equatorial stratospheric background wind QBO.When the stratospheric zonal winds are in an eastward(westward)phase,the airglow emission rates are relatively large(small)and the emission heights are low(high).The phase changes of the zonal winds and the airglow emission show some similarity.The correlation coefficient between the airglow emission time series and the zonal wind time series is the largest when the difference is three months.At higher latitudes,the airglow emission is weakly modulated by the QBO.In addition,the OH airglow emission is modulated by solar activity.We have analysed the relationship between OH airglow emission and solar activity using the10.7 cm solar radio flux as a proxy for solar activity.Our results show that the solar cycle signature in the OH airglow emission rate is stronger than that in the emission height and exhibits a clear latitudinal dependence.We suggest that the solar cycle variations in the OH airglow are more due to chemical than dynamic processes.In the mesopause region,the ozone-hydrogen reaction is the main reaction for the production of OH airglow,while atomic oxygen is required for ozone production.Therefore,the change in OH airglow emission rate will be mainly determined by the change in atomic oxygen.The Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension(SD-WACCM-X)outputs atomic oxygen concentration data representing the vertical transport of atomic oxygen.The results show that an increase in airglow emission rate and a decrease in emission height are associated with downward transport of atomic oxygen.Comparing with the migrating diurnal tide(DW1)amplitude calculated from the temperature data observed by SABER,the DW1 amplitude at 85 km altitude in the equatorial region exhibits SAO and QBO,with the maximum amplitude occurring near the spring equinox.The OH airglow emission in the equatorial region,like the DW1 amplitude,exhibits SAO and QBO due to the corresponding tidal variations of atomic oxygen caused by vertical motion.更多还原