日全食期间中间层大气臭氧光化过程试验

利用包括活O_x、HO_x、和NO_x等成份在内的一维时变光化模式,研究了日全食时上中层大气臭氧和O₂(1△g)的变化特性,并通过与观测资料的比较进行了光化模式的试验.结果表明,日全食时太阳辐照变化对1.27μm气晖影响的高度比曙暮期间明显偏低,利用1.27μm气晖光度计测量大气臭氧的高度范围约为52-67km.1997年3月9日漠河日全食时测量的大气臭氧含量变化幅度为50％.这与考虑O_x、HO_x、和NO_x等成份的光化模式理论模拟结果基本一致.它表明在52-67km高度范围不存在臭氧亏损现象.      

地磁暴期间中、低纬度地区大气臭氧含量的变化

本文分析了1966—1983年不同类型磁暴期间大气臭氧含量的变化。分析结果表明,不同类型磁暴发生时,臭氧含量均有明显的变化,但其特征是不相同的。G_C暴出现时在第6天[O₃]出现明显的下降;S_I暴出现时在第3天和第4天出现较大的下降;S_C暴中的S_A暴对[O₃]的扰动幅度最大,最大下降出现在第1天;S_B暴发生时,[O₃]最大下降出现在第2天;S_D和S_d暴期间[O₃]也在第2天下降到最小值;S_b暴发生时,[O₃]则在0天出现最小值。当这些暴出现时,[O₃]的扰动幅度依次减小,但不论哪种暴发生的前一天,[O₃]都有一个明显的增加。      

受控生态生保系统内红萍供氧特性研究

研究红萍载人供O₂特征, 为红萍生物部件进行系统总体地面模拟试验及空间应用奠定基础,构建了受控生态生保系统密闭试验舱和红萍栽培装置, 在“红萍-鱼-人”共存情况下, 测定密闭舱内O₂, CO₂浓度的变化. 试验结果显示, 单位重量的鱼耗O₂量. 0805～0.0831 L·kg-1·h-1, 排放CO₂量为0.0705～0.0736 L·kg-1·h-1; 试验志愿者耗O₂量19.71 L·h-1, 呼吸释放CO₂量18.90 L·h-1. 人工光照保持7000～8000 lx条件下, 红萍的光合作用与人和鱼的呼吸作用相辅相成, 舱内O₂, CO₂浓度趋于平衡. 密闭舱内CO₂浓度升高对促进红萍群体净光合效率有明显效果, 红萍光合放O₂能力很强, 能有效促使密闭舱内O₂, CO₂浓度朝着有利于人生存的环境方向平衡, 进而验证了红萍的空间应用前景.      

臭氧9.6μ带总吸收比的实验测定

在室温(约18℃)下测定了臭氧(O₃)9.6μ带的总吸收比,O₃含量在0.0188-0.5atmcm,压力在17—760mmHg之间。实验中使用了十字型吸收池,其一支通过紫外线,用以测量臭氧含量;另一支通过红外线,用以测量臭氧9.6μ带的总吸收比。对实验数据应用光谱模式理论进行了分析和处理,结果表明本实验资料与统计模式符合。最后给出了适用于统计模式的带参数。      

星载全球大气波动成像仪研究

在卫星上对中间层顶区域的气辉辐射成像观测, 对于全球大气波动的监测和研究具有重要的意义. 利用TDICCD对O₂A (0-0)气辉进行成像观测, 计算了曝光积分时间、信噪比和能达到的最高空间分辨率, 分析了地球自转对空间分辨率的影响, 在此基础上提出一种星载全球大气波动成像仪方案, 该方案可以观测垂直波长大于10km的大气波动, 最高水平分辨率可以达到0.33km.      

重力波对中间层和低热层大气环流的影响

利用β通道准地转近似大气平均运动方程组,采用重力波线性饱和参量化方法,定性地研究大气重力 波对中间层和低热层大气环流的作用.模拟计算得到,大气重力波对平均东西风速可产生100m·s-1／d左右的作 用力和产生120 m2/s的湍流扩散,这些作用平衡了Coriolis扭力,导致大气的平均东西风速大大偏离辐射平衡 风场,中层顶附近的平均东西风速在冬季(夏季)甚至反转为东风(西风).平均东西风速计算结果与冬季和夏季 中频雷达东西风速观测值和大气模式剖面等大致一致.     

基于钠激光雷达观测数据的中间层顶大气温度分布特性研究

作为中间层和热层的边界层,中间层顶存在多种能量交换方式,是大气能量耦合的重要区域。本文利用部署于中国科学院廊坊临近空间大气探测站的钠荧光多普勒激光雷达2013年的观测数据,研究了廊坊上空中间层顶区域大气温度的年度和季节分布特性,并分析了影响温度分布的多种因素。年平均温度廓线图显示,中间层顶位于约97.5 km高度处,温度约191.2 K。受放热化学反应的影响,年平均温度廓线91 km高度处出现了一个198 K的相对温度高点。中间层顶区域大气温度的季节分布受太阳辐射和大气动力学因素综合影响,夏季在大气动力学影响下,中间层顶高度较低,位于88 km高度处,温度也较低,约177 K;冬季太阳辐射起主导作用,中间层顶位于99 km高度处,温度为181 K。通过拟合月平均温度分析了中间层顶区域大气温度年变化和半年变化的振幅和相位特征。结果显示,中间层顶区域上部温度分布主要受太阳辐射的影响;在中间层顶区域下部,大气波动主导了温度分布。      

美国标准大气1976的几点分析

本文分析了美国标准大气1976的大气参数表及制定的物理假设, 其主要结果是:1.可用绝对温度来定义整个温度剖面T(Z), 而不用“分子量温度”T_M。2.温度剖面的椭圆段在110公里处引进了一个量级为10-7J/m3·s的过大散热源。3.看来大气参数表中唯一的“系统”错误是导热系数。4.详细讨论了联结均匀大气层和高层非均匀大气计算的各种可能途径。5.建议在高层大气模式中引进CO₂分量并降低计算界面到80公里。      

利用曙暮气辉光度观测研究钠层

通过对钠原子曙暮气辉的18次观测确定了北京北郊上空不同季节钠原子气柱总含量和钠层重心高度等结构参数。结果表明:春夏季钠层重心位置高,秋冬季位置低.冬季观测的平均钠层重心高度为85.67公里;钠原子气柱总含量冬季明显高于其它季节,1月和12月的含量约为6月的7.5倍;冬季钠层也相对地厚.钠层重心高度及总含量的季节变化不仅受D层顶中性和离子化学的制约,而且受到垂直风及子午向或纬向环流的很大影响.     

离子温度对磁化等离子体中非线性静电波的影响

本文讨论了无碰撞磁化低β等离子体中离子温度对非线性静电波的影响。结果表明,在参量α≡T_i/T_e≠0条件下,存在着三种非线性静电波(T_i和T_e分别为离子和电子的热能):在波速ν_p>(1+α)(1/2)c_s情况下存在着非线性离子回旋周期波;在(1+α)(1/2)c_scosθp<(1+α)(1/2)c_s情况下存在着离子声孤立波;在v_p<(1+α)(1/2)c_scosθ情况下存在着非线性离子声周期波。当参量α增加时,孤立波的波幅(最大电位)减小,而另外两种非线性周期波的电位幅度都几乎保持不变。      

A review on the upper atmospheric sodium observations from India: Insights

This review article briefly brings out the historical development of atmospheric sodium (Na) measurements over India and the importance of coordinated measurements with multiple techniques to address physical processes in the Earth's upper atmosphere. These measurements were initiated in the early 1970s by observing Na airglow emission intensities with broad band airglow photometer from Mt. Abu, a low-latitude hill station in India. Considerable amount of night-to-night variations in nocturnal emission intensities of the Na airglow were observed. Later, investigations regarding the dependence with the magnetic activities from the equatorial and low latitudes were carried out and double-humped structures in the nocturnal variation of intensities were reported. With the advent of Na lidar at Gadanki around 2005, the measurements of atmospheric neutral Na atom concentration became possible and more frequent occurrences of sporadic Na layers over the magnetic low latitude station compared to other latitudes were detected indicating the role played by electrodynamics. Later, a possible relationship between E-region field aligned plasma irregularities and the concentration of neutral Na atoms was investigated using coordinated measurements of VHF radar and Na lidar. Further, simultaneous measurements with Na lidar and a narrow band airglow photometer with narrow field of view brought out the importance of coordinated observation wherein the characterization of gravity waves could be carried out and also revealed the importance of collisional quenching due to ambient molecules in the Na airglow emission processes. In addition, combining the ground based measurements of Na lidar and meteor wind radar along with satellite measurements made possible to hypothesize the over-turning Kelvin–Helmholtz billow in the Na layer manifests “C-type” or inverted lambda shape structures in the height-time-concentration map of neutral Na atoms. This review paper presents a synoptic view mostly based on the previously reported observations of Na airglow emission, Na lidar and coordinated Na airglow and Na lidar observations from the Indian sector and highlights the importance of simultaneous measurements of mesospheric Na and its emissions along with satellite-borne measurements to address interesting geophysical processes in the Earth's upper atmosphere.     

Temporal variation of the volume emission rates between OI5577 and O2(0,1)

The intensities of the upper mesospheric airglow emissions, OI 557.7 nm and O₂(b) atmospheric (0,1) band at 864.5 nm, have been measured since October 1998 using a ground-based multichannel airglow photometer located near the equator at São João do Cariri (7S, 35W). The intensity ratio between the two emissions, OI5577/O₂b(0,1), was obtained as a function of time. The annual average of the ratio R in 1998 was 0.41 ± 0.14, and showed considerable day to day variations, ranging from 0.2 to 0.6. Nocturnal variations of the ratio also demonstrate a large amplitude of oscillation, varying between 0.3 to 0.6. These results were compared with a model calculation.     

Imaging spectroscopy of the Venus 1.27-μm O2 airglow with ground-based telescopes

Several ground-based observations of the Venus 1.27-μm O₂ airglow were carried out from 2002 to 2005. Spectral image cubes were taken with the Okayama Astrophysical Observatory/infrared imaging spectrometer (superOASIS), the Gunma Astronomical Observatory/Cassegrain Near-Infrared Camera and NASA’s Infrared Telescope Facility/cryogenic echelle spectrograph (CSHELL). The brightest airglow features were found at around the anti-solar point, which is in agreement with previous studies. We derived the rotational temperature distributions on the nightside hemisphere from observed airglow spectra. The temperature shows a weak positive correlation with the airglow intensity. The result indicates the bright region is heated chemically and/or dynamically, and supports the existing scenario for the Venus O₂ airglow. That is, the airglow is excited by the descending oxygen transported from the dayside.     

New possibilities for mesospheric electricity diagnostics

A possible cause of large variations in the electron collision frequency could be the effect of strong external electric fields of atmospheric origin. This provides a new opportunity to take measurements of electric fields in the lower ionosphere using remote sensing instruments employing radio wave techniques. It has been proposed the technique for making estimates of strong mesospheric electric field intensities on the lower edge of the ionosphere using MF radar data on the effective electron collision frequency, and the data has been presented. The technique described permits a real-time derivation from MF radar data of changes in mesospheric electric field intensities, and estimates of electric current densities. Our results give proof that the source of strong mesospheric electricity is very likely to be a current source.     

高层大气臭氧对于太阳紫外辐射27天波动的响应

本文利用Ｓｏｌａｒ Ｍｅｓｏｓｐｈｅｒｅ Ｅｘｐｌｏｒｅｒ（ＳＭＥ）卫星１９８２年和１９８３年太阳紫外辐射和赤道地区５０－９０ｋｍ臭氧分布的红外观测资料，对臭氧地太阳紫外辐射２７天振荡的响应进行了研究，并且利用大气光化波动模式对其进行了理论计算，计算结果与实测结果基本一致。     

Characterization of the semi-annual-oscillation in mesospheric temperatures at low-latitudes

Novel measurements of the seasonal variability in mesospheric temperature at low-latitudes have been obtained from Maui, Hawaii (20.8°N, 156.2°W) during a 25-month period from October 2001 to January 2004. Independent observations of the OH (6, 2) Meinel band (peak height ∼87 km) and the O₂ (0–1) atmospheric band emission (∼94 km) were made using the CEDAR Mesospheric Temperature Mapper. The data revealed a coherent oscillation in emission intensity and rotational temperature with a well-defined periodicity of 181 ± 7 days. The amplitude of this oscillation was determined to be ∼5–6 K in temperature and ∼8–9% in intensity for both the OH and O₂ data sets. In addition, a strong asymmetry in the shape of the oscillation was also observed with the spring maximum significantly larger than the fall peak. These data provide new evidence in support of a semi-annual-oscillation in mesospheric temperature (and airglow emission intensities) and help quantify its seasonal characteristics.     

Validation of 9.6 μm ozone transmittances by spectral radiance satellite measurements

The accuracy of atmospheric transmittances is important in remote sensing applications. In this paper the atmospheric ozone transmittances in the 1042 cm^?1 ozone band were calculated for different temperatures and ozone profiles using line-by-line integration method. The absorption line parameters were taken from McClatchey's line parameter compilation. The transmittances were used to derive the main characteristics of the atmospheric ozone profile and the total ozone amount from radiance measurements of Meteor satellites.     

Observations of the ozone and nitrogen dioxide profiles in the TROICA-4 experiment

To investigate the vast area of Russia, a mobile scientific facility based in a railway carriage was developed. It is capable to perform continues measurements being coupled in a passenger train traveling along railroads. It was first equipped with a spectrometer for remote sensing of ozone and nitrogen dioxide in the atmosphere for the transcontinental observations into the chemistry of the atmosphere-4 expedition performed from February 18 to March 5, 1998. A twilight DOAS method, which was applied for retrieval of the nitrogen dioxide profiles basing on spectral measurements at the visible wavelengths (434–451 nm), is described in the paper. Main features of a new algorithm for retrieval of the ozone profile and total content using the differential structure of the UV spectrum (310–335 nm) are presented. The ozone and nitrogen dioxide contents are obtained and shortly validated against available alternative data.     

Seasonal variation in the solar diurnal tide and its possible influence on the atmospheric sodium layer

In a paper published 12 years ago, we showed that the height of the atmospheric sodium layer at our location is about 1 km lower in November than at any other time of the year. We also showed that the decrease in height of the sodium layer was accompanied by an increase in the intensity of the OI 557.7 nm and OH(9,4) band airglow emissions. At that time we suggested that this behavior could be the result of large scale convective transport in the MLT region. We have now had the opportunity to compare the diurnal variations of the sodium layer and airglow emissions with the tidal winds measured by meteor radar over the past 5 years. We find that the amplitude of the diurnal tide is much smaller in November than at other times of the year. Since most of the sodium measurements and all of the airglow observations are for night-time conditions only, a change in the amplitude of the 24-h tide could strongly influence the average measured sodium and airglow parameters. It is shown that the observed changes in the tidal winds are qualitatively consistent with the sodium measurements, but the amplitude of the observed height change is much greater than would be expected from the tidal winds.