Method of calibration to correct for cloud-induced wavelength shifts in the Aura satellite's Ozone Monitoring Instrument

The in-flight wavelength calibration for the Ozone Monitoring Instrument is discussed. The observed variability in the wavelength scale is two orders of magnitude larger than caused by temperature changes in the instrument. These wavelength variations are the result of rapid changes in time in the radiance levels during an individual observation in the presence of clouds or snow and ice. We have developed a data processing method to account and correct for these changes. In February 2005 this correction was implemented in the official data processing stream. We explain in detail how and how accurately this method works. Before correction, the error in the wavelength scale can be as much as a few tenths of a pixel; after correction it is mostly less than 1/100th of a pixel, which is the required preflight accuracy. This means that higher-level products such as the total column amounts of ozone, NO2, and SO2 are not significantly affected. It is expected that these wavelength variations will be observed in other hyperspectral Earth observation spectrometers and that the correction mechanism should apply equally well.     

Ratio of oxygen and nitrogen Raman cross sections in the ultraviolet

We report measurements of the ratio of oxygen and nitrogen Raman cross sections for excitation wavelengths between 220 and 290 nm. These measurements confirm strong enhancement of the oxygen Raman cross section in this region.     

Accurate modeling of spectral fine-structure in Earth radiance spectra measured with the Global Ozone Monitoring Experiment

We present what we believe to be a novel approach to simulating the spectral fine structure (<1 nm) in measurements of spectrometers such as the Global Ozone Monitoring Experiment (GOME). GOME measures the Earth's radiance spectra and daily solar irradiance spectra from which a reflectivity spectrum is commonly extracted. The high-frequency structures contained in such a spectrum are, apart from atmospheric absorption, caused by Raman scattering and by a shift between the solar irradiance and the Earth's radiance spectrum. Normally, an a priori high-resolution solar spectrum is used to simulate these structures. We present an alternative method in which all the required information on the solar spectrum is retrieved from the GOME measurements. We investigate two approaches for the spectral range of 390-400 nm. First, a solar spectrum is reconstructed on a fine spectral grid from the GOME solar measurement. This approach leads to undersampling errors of up to 0.5% in the modeling of the Earth's radiance spectra. Second, a combination of the solar measurement and one of the Earth's radiance measurement is used to retrieve a solar spectrum. This approach effectively removes the undersampling error and results in residuals close to the GOME measurement noise of 0.1%.     

The use of nanocarbons as chemical filters for the selective detection of nitrogen dioxide and ozone

The gas filtering abilities of different nanocarbon materials such as nanocones/nanodiscs, and nanofibres, either as-prepared or modified by physical (annealing, grinding) or chemical (fluorination) treatment are reported. The aptitude to filter nitrogen dioxide and ozone, two of the most significant gaseous pollutants of the atmosphere, have been correlated to both the BET specific surface area studied by N2 adsorption at 77 K, and the presence of chemical functional groups at the surface. Valuable information regarding the mechanisms of gas-nanocarbon interaction has been obtained, in terms of chemisorption and physisorption. A prototype microsystem is proposed for the selective measurement of nitrogen dioxide and ozone concentration by means of organic semiconductor gas sensors.     

Cloud Detection and Clearing for the Earth Observing System Terra Satellite Measurements of Pollution in the Troposphere (MOPITT) Experiment

The Measurements of Pollution in the Troposphere (MOPITT) instrument, which was launched aboard the Earth Observing System (EOS) Terra spacecraft on 18 December 1999, is designed to measure tropospheric CO and CH(4) by use of a nadir-viewing geometry. The measurements are taken at 4.7 mum in the thermal emission and absorption for the CO mixing ratio profile retrieval and at 2.3 and 2.2 mum in the reflected solar region for the total CO column amount and CH(4) column amount retrieval, respectively. To achieve the required measurement accuracy, it is critical to identify and remove cloud contamination in the radiometric signals. We describe an algorithm to detect cloudy pixels, to reconstruct clear column radiance for pixels with partial cloud covers, and to estimate equivalent cloud top height for overcast conditions to allow CO profile retrievals above clouds. The MOPITT channel radiances, as well as the first-guess calculations, are simulated with a fast forward model with input atmospheric profiles from ancillary data sets. The precision of the retrieved CO profiles and total column amounts in cloudy atmospheres is within the expected ?10% range. Validations of the cloud-detecting thresholds with the moderate-resolution imaging spectroradiometer airborne simulator data and MOPITT airborne test radiometer measurements were performed. The validation results showed that the MOPITT cloud detection thresholds work well for scenes covered with more than 5-10% cloud cover if the uncertainties in the model input profiles are less than 2 K for temperature, 10% for water vapor, and 5% for CO and CH(4).     

Stable method for the calculation of layered dielectric and metal-dielectric waveguide structures with circular cross sections

A new method intended for the calculation of eigenmodes and leaky modes in layered dielectric and metal-dielectric waveguide structures possessing azimuthal symmetry is described. The proposed method generalizes the approach developed by Golant [1] for the analysis of planar layered structures. The numerical procedure is stable in application to the systems with wave tunneling or decay (instability) in radial directions. Possibilities of the proposed method are demonstrated in calculations of the Bragg optical fibers of various types.     

Spin exchange cross sections for collisions of metastable helium atoms with lithium atoms in the ground state

The spin exchange and chemi-ionization cross sections for the metastable helium atom-lithium atom in the ground state system have been calculated. Using data on the interaction potentials obtained in this study, the spin exchange cross sections are determined for the first time for the He(2³ S ₁)-Li(2² S _1/2) system in the interval of collision energies from 5 × 10^?3 to 16 eV.     

Irregularities in the differential and integral cross sections figures for ion-atom collisions in the plane-wave born approximation

We discuss the generalized oscillator strength (GOS), a fundamental physical quantity that represents the response of an atom to the interaction with a charge. The GOS is related to the differential cross section for excitation in ion-atom collisions in the plane-wave Born approximation (PWBA). The GOS for a particular transition is a function of the momentum transferred from the relative motion to the atom. Approximate scaling of the GOS is sometimes found along an isoelectronic sequence, but is not found for those cases we have studied for which the GOS has a minimum. Two different mechanisms produce minima of the GOS; one is due essentially to nodes of one-electron radial wave functions, and the other is an effect of the configuration interaction that introduces an avoided crossing of energy levels plotted against the nuclear charge. A minimum of the GOS sometimes leads to a double-maximum structure of the integral cross section for ion-atom collisions in the PWBA, though one usually expects the PWBA to produce only one maximum.     

Analysis of the stability and conditions for bulging of gas main line sections laid with an initial curvature

A method is proposed for calculating for the stability of gas main line sections installed with an initial, upwardly convex, curvature. Conditions for the start of stability loss are formulated, and calculated dependences are obtained for determining the deflections and bending moments at the bulged sections.Sverdlovsk. Translated from Problemy Prochnosti, No. 9, pp. 118–121, September, 1989.     

气相色谱法测定电石炉气中氢气、一氧化碳、二氧化碳、甲烷、乙炔气体含量

采用气相色谱法,测定了电石炉气中氢气(H_2)、一氧化碳(CO)、二氧化碳(CO_2)、甲烷(CH_4)、乙炔(C_2H_2)气体的含量。该方法的检测限为H_2≤8.5μmol/mol、CO≤2.8μmol/mol、CO_2≤15.2μmol/mol、CH_4≤0.22μmol/mol、C_2H_2≤0.53μmol/mol。方法简便、快速,并具有较好的准确度和精密度。     

Determination of the kinetic curves of drying of blocks of adsorbents-dessicants with different cross sections of channels and of a granulated adsorbent on a change in the flow velocity

The kinetics of convective drying (regeneration) of different types of adsorbents-dessicants with different geometric parameters has been studied. It is shown that adsorbents of a “channel” (cellular) type have a long constant-rate stage of drying, whereas a granulated polydisperse adsorbent is mainly dried at a variable rate. Adsorbents having a maximum water yielding capacity have been revealed. It has been established that the velocity of a drying gas flow substantially influences the process of moisture extraction from all types of adsorbents. In order to describe the kinetic curves of the given phenomenon, a model of a relaxation kinetic equation that quite satisfactorily describes the kinetics of drying of the adsorbents studied was used. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 82, No. 1, pp. 65–68, January–February, 2009.     

乳化炸药乳化器监测与故障诊断系统中数据库的设计

以数据库设计理论为指导,以某化工厂乳化炸药乳化器安全监测与故障诊断系统为应用背景,设计开发了一个数据库应用系统.给出了数据库的概念设计、逻辑设计和物理设计的实现过程,并结合乳化炸药乳化器安全监测与故障诊断系统给出编程过程中需注意的要点.实践表明该数据库完全符合现场实际需求,实际运行效果良好.     

Feasibility study for joint retrieval of air density and ozone in the stratosphere and mesosphere with the limb-scan technique

Air density is a key sensing object for its high variability especially in the mesosphere, and ozone plays an important role in the physical, chemical, and radiant processes in the atmosphere system. Therefore it is essential to obtain their global vertical distributions jointly with high precision and vertical resolution. There is little work on joint retrieval of air density and ozone distributions using the ultraviolet limb-scan technique, although much work has been done on ozone measurement. Numerical simulations of joint air density and ozone retrieval in the middle atmosphere (20-90 km) are carried out using limb-scattered radiances at four bands (255, 300, 320, and 340 nm). Results show that joint retrieval of dual parameters using the limb-scan technique is feasible with high precision in nearly the whole region concerned, where air density and ozone have a precision of 1%-2% and 3%-5%, respectively, provided that high measurement precision and accurate correction of multiple-scattered radiance at long ultraviolet bands are ensured.     

静态质量法小口径流量计检定装置控制系统中干扰因素分析及措施

静态质量法小口径流量计检定装置中 ,采用计算机对检定过程进行控制 ,由于现场存在电磁动力设备和其他影响因素 ,因此要保证控制系统稳定可靠地运行 ,必须对控制系统实行抗干扰措施     

朝鲜半岛构造系统地质环境演化及动力学机制的地球卫星遥感影像解译研究

采用将东亚地区综合资料分析成果与地球卫星遥感影像解译相结合的方法,深入研究了全球构造域中典型的构造地段朝鲜地块。详细识别出朝鲜半岛地区的基本构造形式,其基本类型主要有环形构造（及辐射构造）、追踪构造、共轭构造、菱形构造、多米诺构造等;对其构造地质环境演化过程及地球动力学机制进行了宏观阐述,晚古生代之前朝鲜半岛是由中国东部三个不同板块（华北板块;扬子板块、华南板块）贴拼焊接而成,中生代隆起成陆以后遭受了三期构造运动的影响（松林运动、大宝运动、佛国寺运动）,新生代发生了玉岭运动。朝鲜地块基本构造形式的形成受中国边缘海盆地与日本海盆地的侧向水平运动的影响,其构造主应力轨迹线方向为北东-南西向延伸,近代主应力轨迹线方向表现为北西西-南东东向展布,对其引起的现代地质作用及环境效应得到有关部门的充分注意。     

Method of spectral compensation and its application in the ultraviolet for sulfur dioxide control with a gas-filter correlation instrument

Changes in structureless spectra that are due to the presence of interfering absorbers or light source instabilities, changes in the spectral transfer function of the optics, and changes in the detector's spectral responsivity degrade measurement accuracy. A method of compensating for changes in structureless spectra is developed for a gas-filter correlation instrument. It is shown that there are points in the spectrum where the effect of the interfering component's having a structureless spectrum on the measurement can be drastically reduced.