Measurement of stratospheric trace constituent distributions from balloon-borne far infrared observations

Far infrared limb thermal emission spectra obtained from balloon borne measurements made as a part of the Balloon Intercomparison Campaign (BIC) have been analyzed for retrieval of stratospheric trace constituent distributions. The measurements were made with a high resolution Michelson Interferometer and covered the 15–180 cm⁻¹ spectral range with an unapodized spectral resolution of 0.0033 cm⁻¹. The retrieved vertical profiles of O₃, H₂O, HDO, HCN, CO and isotopes of O₃ are presented. The results are compared with the BIC measurements for O₃ and H₂O made from the same balloon gondola and with other published data. A comparison of the simultaneously retrieved profiles for several gases with the published data shows good agreement and indicates the validity of the far infrared data, the retrieval techniques and the accuracy of the inferred profiles.     

The Nonlinear Model of the Response of Airglow to Gravity Waves

In this paper, we develope a time-dependent, nonlinear, photochemical-dynamical 2-D model which is composed of 3 models: dynamical gravity wave model, middle atmospheric photochemical model, and airglow layer photochemical model. We use the model to study the effect of the gravity wave propagation on the airglow layer. The comparison between the effects of the different wavelength gravity wave on the airglow emission distributions is made. When the vertical wavelength of the gravity wave is close to or is shorter than the thickness of the airglow layer, the gravity wave can make complex structure of the airglow layer, such as the double and multi-peak structures of the airglow layers. However, the gravity wave that has long vertical wavelength can make large scale perturbation of the airglow emission distribution.     

重力波对中层顶区光化加热的影响

计算了重力波过程对光化加热的影响,并研究了不同温度背景及不同氧原子的背景分析对该过程的影响,计算表明重力波可以造成中层顶光反应加热的损失。     

利用WACCM-3模式对平流层动力、热力场及微量化学成分季节变化的数值模拟研究

利用美国NCAR最新的化学-气候耦合模式WACCM-3对平流层风场、温度场以及平流层臭氧等多种微量气体成分(O3, CH4, N2O, H2O, HCl, HNO3)的季节变化进行了数值模拟, 并使用ECMWF再分析资料与美国UARS卫星 搭载的HALOE, MLS, CLAES等探测器的观测资料, 对模式输出的动力、热力及化学成分浓度的气候平均值进行了验证. 结果表明, 在气候平均海表温度值驱动下, WACCM-3模式能够很好地再现ECMWF资料中平流层纬向平均风场与温度场的季节变化. 模拟结果中平流层化学成分的经向-垂直分布及其季节变化与卫星观测结果基本一致. 模式的动力、热力场在极地平流层以及热带对流层顶等区域存在一定的偏差. 这些偏差对于微量气体成分分布 的模拟具有一定影响, 特别是南半球冬(7月)、春(10月)季节南极平流层低层极夜 急流偏强, 造成极地地区附近的输送障碍增强, 从而导致CH4, N2O, H2O浓度比观测偏低. 此外, WACCM-3缺少热带平流层风场的准两年振荡(QBO) 机制, 这对于热带平流层东风急流以及低纬度平流层O3, CH4, N2O, H2O等成分经向输送的模拟结果也有一定影响.      

Photochemical growing of complex organics in planetary atmospheres

UV induced syntheses of organic compounds from the main atmospheric constituents can be a very important source of organics in a given planetary environment provided the atmosphere is in a reduced state. The evolution of a CO₂ rich medium only produces very low yields of formaldehyde and related oxygenated compounds. Considering a CO rich atmosphere, the photochemical yield of O-organics formation is much higher, when the synthesis of N-organics remains difficult. The most favourable atmosphere as far as photochemical organic synthesis is concerned is a CH₄ rich milieu.. The photochemical evolution of such a CH₄ atmosphere under UV irradiation leads to a chain of various organics, the complexity of which increases together with the number of pathways involved in their formation. Their complexity also closely correlates with their UV photoabsorption spectrum: the more complex they are, the more shifted is their UV spectrum toward the visible range. Direct photodissociation of methane requires UV photon of wavelengths shorter than about 145 nm. It mainly produces ethane which absorbs UV at wavelengths shorter than about 160 nm, and acetylene, that presents an absorption spectrum extending up to 200 nm. This shift still continuously increases with further increase in number of C atoms. Unsaturated hydrocarbons with 4 and more C atoms have UV absorption characteristics including noticeable band structures in the 250–300 nm range. This trend has very important implication in the photochemical behaviour of a CH₄-rich planetary atmosphere, as it induces many catalytic processes. The occurrence of such processes is closely related to vertical atmospheric and energy deposition profiles. Titan provides a very good example of such a UV-directed organic atmospheric chemistry.     

Results from the LIMS experiment for the PMP-1 winter 1978/79

The Limb Infrared Monitor of the Stratosphere (LIMS) experiment utilized a 6-channel limb scanning infrared radiometer on the Nimbus 7 spacecraft, for the purpose of determining global distributions of temperature and trace constituents in the middle atmosphere (15–65 km) with high vertical resolution.LIMS observations provide a detailed picture of atmospheric variability during the disturbed winter of 1978/79. During January and February, three large disturbances caused simultaneous temperature changes through most of the global middle atmosphere. The amplitudes and phases of the planetary temperature and height waves show large variations during this time. Their values and derived quantities are larger than those resulting from data with lower vertical resolution. The Eliassen-Palm fluxes calculated for late January are in qualitative agreement with the observed acceleration of the zonal winds.     

利用热力学与统计物理方法研究电离层E层的形成

将太阳光子作为反应物引入电离层化学反应中, 运用化学热力学方法, 获得低电离层光化学反应的反应度及其化学平衡常数, 进而得到低电离层的电子密度, 并通过统计物理方法推导出相应的化学平衡常数. 结果显示, 运用热力学方法得到的低电离层电子密度与Chapman理论几乎完全一致, 表明利用热力学方法研究电离层的形成是可行的. 分别用热力学方法和统计物理方法得到的平衡常数之间存在一定的差异, 分析表明, 这是因为光化学过程中并非所有光子能量都转化成了电离能, 其中有一部分能量转化为热能或使粒子处于激发态, 这种差异的存在使利用统计物理方法推导电离层等离子体温度成为可能.      

Post-midnight equatorial irregularity distributions and vertical drift velocity variations during solstices

Longitudinal distributions of post-midnight equatorial ionospheric irregularity occurrences observed by ROCSAT-1 (1st satellite of the Republic of China) during moderate to high solar activity years in two solstices are studied with respect to the vertical drift velocity and density variations. The post-midnight irregularity distributions are found to be similar to the well-documented pre-midnight ones, but are different from some published distributions taken during solar minimum years. Even though the post-midnight ionosphere is sinking in general, longitudes of frequent positive vertical drift and high density seems to coincide with the longitudes of high irregularity occurrences. Large scatters found in the vertical drift velocity and density around the dip equator in different ROCSAT-1 orbits indicate the existence of large and frequent variations in the vertical drift velocity and density that seem to be able to provide sufficient perturbations for the Rayleigh-Taylor (RT) instability to cause the irregularity occurrences. The need of seeding agents such as gravity waves from atmospheric convective clouds to initiate the Rayleigh-Taylor instability may not be necessary.     

临近空间大气化学过程快速建模技术初探

围绕临近空间大气化学过程数值模拟计算问题,以平流层大气4个典型光化学系统为例,运用化学动理学预处理(KPP)工具,对不同复杂度的光化学反应质量平衡方程体系进行预处理,快速建立各系统化学动理学方程组的代数表示;针对模型中的大刚性ODE方程组,选取6种不同的数值计算方案(rodas,ros3,ros4,rosenbrock...     

Ozone chemical equilibrium in the extended mesopause under the nighttime conditions

For retrieval of atomic oxygen and atomic hydrogen via ozone observations in the extended mesopause region (～70–100?km) under nighttime conditions, an assumption on photochemical equilibrium of ozone is often used in research. In this work, an assumption on chemical equilibrium of ozone near mesopause region during nighttime is proofed. We examine 3D chemistry-transport model (CTM) annual calculations and determine the ratio between the correct (modeled) distributions of the O₃ density and its equilibrium values depending on the altitude, latitude, and season.The results show that the retrieval of atomic oxygen and atomic hydrogen distributions using an assumption on ozone chemical equilibrium may lead to large errors below ～81–87?km. We give simple and clear semi-empirical criterion for practical utilization of the lower boundary of the area with ozone’s chemical equilibrium near mesopause.     

An investigation into the roles of ECH and whistler mode waves in the formation of “pancake” electron distributions using data from the CRRES satellite

Electron pitch angle distributions sharply peaked at 90° pitch angle were first recorded in the energy range 50 eV < E < 500 eV by the GEOS-1 and GEOS-2 spacecraft in 1977/8, from the plasmapause out to geostationary orbit. At the time they were explained as the remnants of pitch angle diffusion driven solely by Electron Cyclotron Harmonic (ECH) waves. Here we use observations by instruments on board the CRRES spacecraft to study these distributions in more detail. The pancake distributions are now seen to develop from injected distributions that are nearly isotropic in velocity space, on a time scale that is greater than 2 hours. The freshly injected distributions are associated with strong ECH and whistler mode waves suggesting that the pancake distributions are likely to be caused by a combination of both wave types. Our results suggest that whistler mode waves play a dominant role in the formation of pancake distributions outside L = 6.0, whereas inside L = 6.0 and, in particular, in the vicinity of the plasmapause, the ECH waves also play a significant role. Consequently both types of waves should be considered in any attempt to explain the diffuse aurora and the variation with L taken into account.     

氧气A(0,0)波段气辉体发射率和临边辐射强度模拟与分析

临近空间大气参数如温度、密度、风场等对预报模型精度及航天器运行安全等有较大的影响,而气辉的辐射模拟是大气参数反演的重要过程.本文基于光化学模型计算了氧气A（0,0）波段气辉的体发射率和临边辐射强度.基于氧气A（0,0）波段气辉的光化学反应机制、大气动力学和光化学反应理论,建立产生O₂（b1Σ_g+）的光化学模型.计算气辉体发射率,基于临边探测几何路径进行气辉辐射强度模拟.体发射率计算结果与AURIC模型结果的辐射值及辐射高度均一致.基于计算和模拟结果,对氧气A波段气辉体发射率和辐射强度的影响因素进行了分析.      

基于NOAA卫星数据的辐射带质子投掷角分布研究

利用NOAA-12卫星数据对空间环境平静时期太阳同步轨道处辐射带质子投掷角分布进行了研究. 根据投掷角分布的经验公式,计算出90°投掷角的质子方向强度和各向异性指数n. 质子投掷角分布按n的取值范围可分为三类,即90°峰值分布、平顶分布和蝴蝶形分布. 观测证实,对于辐射带质子,三种分布类型均存在并且具有明显的空间区域特征. 在内辐射带边缘地区90°峰值分布占主要优势;在外辐射带高L值区域,90°峰值分布明显减少,平顶分布和蝴蝶形分布逐渐增多. 针对90°峰值分布,研究了质子强度各向异性的区域分布特征,对于内辐射带区域,n值随L值的增大而增大,对于外辐射带,n值表现为逐渐下降的趋势. 为了研究质子投掷角分布对磁地方时的依赖关系,分析了能量为250～800keV的质子在两个不同磁地方时范围的投掷角分布规律. 结果显示,在内辐射带,质子强度的投掷角分布相对稳定,随磁地方时的变化并不显著;而在外辐射带的高L值区域,质子强度的投掷角分布随磁地方时变化明显,与磁地方时之间有明显的依赖关系.      

Recycling of trace elements required for humans in CELSS.

Recycle of complete nourishment necessary for human should be constructed in CELSS (Controlled Ecological Life Support Systems). Essential elements necessary for human support are categorized as major elements, semi-major elements and trace elements. Recently, trace elements have been identified from considerations of local diseases, food additive problems, pollution problems and adult diseases, consisting of Fe, Zn, Cu, Se, Co, F, Si, Mn, Cr, I, As, Mo, Ni, V, Sn, Li, Br, Cd, Pb, B. A review of the biogeochemical history of the earth's biosphere and the physiological nature of humans and plants explains some of the requirements. A possible route for intake of trace elements is considered that trace elements are dissolved in some chemical form in water, absorbed by plants through their roots and then transfered to human as foods. There may be a possibility that living things absorb some trace elements from atmosphere. Management and recycling of trace elements in CELSS is discussed.     

Photoinduced catalytic synthesis of biologically important metabolites from formaldehyde and ammonia under plausible “prebiotic” conditions

The article analyzes new and previously reported data on several catalytic and photochemical processes yielding biologically important molecules. UV-irradiation of formaldehyde aqueous solution yields acetaldehyde, glyoxal, glycolaldehyde and glyceraldehyde, which can serve as precursors of more complex biochemically relevant compounds. Photolysis of aqueous solution of acetaldehyde and ammonium nitrate results in formation of alanine and pyruvic acid. Dehydration of glyceraldehyde catalyzed by zeolite HZSM-5-17 yields pyruvaldehyde. Monosaccharides are formed in the course of the phosphate-catalyzed aldol condensation reactions of glycolaldehyde, glyceraldehyde and formaldehyde. The possibility of the direct synthesis of tetroses, keto- and aldo-pentoses from pure formaldehyde due to the combination of the photochemical production of glycolahyde and phosphate-catalyzed carbohydrate chain growth is demonstrated. Erythrulose and 3-pentulose are the main products of such combined synthesis with selectivity up to 10%. Biologically relevant aldotetroses, aldo- and ketopentoses are more resistant to the photochemical destruction owing to the stabilization in hemiacetal cyclic forms. They are formed as products of isomerization of erythrulose and 3-pentulose. The conjugation of the concerned reactions results in a plausible route to the formation of sugars, amino and organic acids from formaldehyde and ammonia under presumed ‘prebiotic’ conditions.     

基于LMI的过渡态主控回路闭环控制律优化设计

针对涡扇发动机过渡态多变量控制设计难的问题，提出了一种基于抽功法在过渡态加减速线上的准稳态工作点处提取线性模型的方法，并在此基础上提出了一种过渡态主控回路闭环控制律的优化设计方法。通过功率输入和功率提取解决过渡态动态特征提取难题，基于增益调度可作为非线性动态控制策略的基本原理，将稳态多变量控制规律的线性矩阵不等式(LMI)设计方法推广到涡扇发动机过渡态主控回路闭环控制的设计中，并通过最小化矩阵迹优化闭环极点配置。针对2种不同过渡态主控回路闭环控制策略，分别设计了最小化矩阵迹寻优的过渡态主控回路的多变量闭环控制律，并进行从慢车到中间状态的基于涡扇发动机非线性动态模型的双通道过渡态性能仿真验证，结果表明:方案1过渡态控制双通道N₁、N₂的调节时间不大于5.0 s，超调量不大于0.8%；方案2过渡态控制双通道π_T、N₂的调节时间不大于5.6 s，超调量不大于0.8%。      

核电站工作场所中子能谱和周围剂量当量率测量

中子周围剂量当量是核电站辐射防护监测的主要对象之一,而中子周围剂量当量的评估强烈依赖中子的能量分布。利用自制的多球谱仪对秦山第三核电有限公司（TQNPC）重水反应堆安全壳内5个位置的中子能谱和周围剂量当量率进行了测量。该谱仪由1个³He正比计数器以及9个2.5～12英寸不同直径的聚乙烯球组成,响应函数通过MCNP程序计算,并利用标准²⁵²Cf中子源进行了校准和验证。通过测量的中子能谱,获得了不同工作区域的中子周围剂量当量率及其能量分布,并与中子周围剂量当量率仪和CR-39径迹蚀刻探测器的测量结果进行了比较,为核电站中子剂量的监测提供了相关参考数据。     

Photochemistry of planetary ionospheres

The basic photochemical processes in the upper atmospheres and ionospheres of the various bodies in our solar system (planets, moons and comets) are similar. However, there are many different factors (e.g. gas composition, energy input, gravity) which control/change the relative importance of these controlling processes. The photo-chemistry of the inner planets is reasonably well understood at this time, thus there is good agreement between model calculations and most of the observational data base. The extremely limited information that we have available on the ionospheres of the outer planets leads to significant uncertainties about some of the controlling processes. Some important questions (e.g. Is the charge exchange process H⁺ + H₂(v≥4) → H₂⁺ + H important? Is water vapor influx from the rings important?) remain unanswered at this time. In cometary atmospheres the freshly evaporated parent molecules are rapidly photodissociated and photoionized, therefore most of the chemical kinetics of cometary ionospheres involve these rapidly moving and highly reactive ions and radicals.     

Experimental simulation of proton space radiation environments: a dosimetric perspective.

Three-dimensional dose calculation techniques developed for radiotherapy treatment planning were used to calculate dose distributions from unidirectional, planar rotational and omnidirectional incident radiation (experimental proton beams and solar flares). The calculations predicted regions of high dose within primate heads exposed to 55-MeV protons, supporting the postulate of radiation-induced brain tumors within this population. Comparisons among predicted doses to the human head from solar flares of three different energies demonstrated differences between unidirectional and omnidirectional irradiation in the space environment. The results can be used to estimate dose distributions based on a) limited phantom measurements, or b) nonuniformly incident radiation in orbit; both situations are difficult to replicate under laboratory exposure conditions.     

中层大气钠层的流星蒸发模式

本文计算了地球中层大气的钠层模式。在此模式中,流星蒸发是形成钠层的源而尘埃的吸附足汇。本文考虑和比较了有关钠层形成机制的已往工作中所出现过的所有光化学反应,选出了四十个合理而重要的化学反应作为本模式的化学基础。模式也考虑进了高度变化的涡流扩散和带电粒子受地磁场作用的向下飘移等机制。本文对各化学反应和模式中各个因素的重要性作了比较和评价。本文计算结果表明,在各高度上中层大气中的钠及其化合物的相对浓度主要取决于化学反应过程本身,与源、汇及各层间扩散机制等关系不大。虽然在钠层模式计算中必须考虑到十种钠成分,但105公里以上主要成分足钠离子(Na+)。80公里以下主要成分是氢氧化钠(NaOH)。80公里到105公里间主要成分是中性钠原子(Na)。所有成分的总浓度主要地取决于源和汇随高度的分布。大气背景及电离常数的变化可以引起钠层相当显著的季变化和周日变化。理论计算结果与历年来的观测结果作比较后可以看到两者大体上符合得相当好。