瑞利激光雷达探测南京上空平流层大气温度

为了解平流层大气温度变化规律,利用瑞利-拉曼-米散射激光雷达对南京上空平流层温度进行长期观测,对观测数据的分析表明:夜晚平流层温度受到重力波的影响,重力波破碎会导致局部温度升高,温度相对变化可以达到12%;在季节变化的过渡月份(4月和10月),平流层中低层温度会有所升高,对应的平流层高层温度降低;平流层温度月变化方面,除局部由于行星星际波的影响外,各月份平流层温度整体上相对比较稳定,激光雷达所测大气温度与大气模式温度具有一定的差别。最后,利用平流层温度廓线提取了重力波信息。     

瑞利激光雷达探测南京上空平流层大气温度

为了解平流层大气温度变化规律,利用瑞利-拉曼-米散射激光雷达对南京上空平流层温度进行长期观测,对观测数据的分析表明：夜晚平流层温度受到重力波的影响,重力波破碎会导致局部温度升高,温度相对变化可以达到12%;在季节变化的过渡月份（4月和10月）,平流层中低层温度会有所升高,对应的平流层高层温度降低;平流层温度月变化方面,除局部由于行星星际波的影响外,各月份平流层温度整体上相对比较稳定,激光雷达所测大气温度与大气模式温度具有一定的差别。最后,利用平流层温度廓线提取了重力波信息。     

On the possible perturbation of stratospheric dynamics due to Pinatubo aerosols

Summary The injection of a large amount of SO₂ in the tropical lower stratosphere following the eruption of Mt. Pinatubo (15.1^oN, 120.4^oE; June 15, 1991) can produce a not negligible perturbation in the stratospheric dynamics. Sulfate aerosols formed by nucleation of H₂SO₄ vapour, which is in turn produced from the SO₂ plume, are responsible for a net heating of the order of 0.15K/day in the equatorial stratosphere, located where the thickest portion of the aerosol cloud is found. As shown by recent satellite data, this diabatic perturbation is responsible for a temperature increase of the order of (2÷3) K at 30m bar during the summer and fall of 1991, that is similar to what found for the 1982 eruption of El Chichón. In this work we use a stratospheric three-dimensional model to investigate the dynamical response of the middle atmosphere to this diabatic forcing. Few months after the eruption, change in the diabatic circulation larger than 10% is found in the lower stratosphere, along with a stronger planetary wave activity during the 1991/92 winter season. This supports some conclusions of a recent investigation by Dunkerton and Delisi on the effects of the 1982 eruption of El Chichón and is shown to have a substantial effect on trace species transport, comparable to that associated to the Quasi-Biennal Oscillation (QBO).     

Sensitivity of stratospheric ozone lidar measurements to a change in ozone absorption cross-sections

The effect of a change in ozone absorption cross-section data is evaluated for stratospheric ozone lidar measurements, which are regularly performed for the monitoring of the ozone layer. The change is analysed for the measurements based on both the elastic and Raman scattering of the laser light by the atmosphere. The latter technique is essentially used for measurements performed in the presence of volcanic aerosol layers in the stratosphere. The discrepancy in ozone number densities is evaluated for various ozone cross-section data sets, using an atmospheric model for the evaluation of ozone cross-section temperature dependence. Results show that the difference in both elastic and Raman DIAL retrievals is below 1.5% in absolute values from 10 to 30 km. Above 30 km, the difference, estimated for the elastic DIAL retrieval only, is maximum around 45 km, with largest differences reaching 1.8% in the tropics.     

Arrival of Pinatubo disturbances in the stratospheric aerosol layer over Fort Collins,CO, observed by a lidar at 589 nm

Using the Colorado State Na Lidar, surges of stratospheric aerosols caused by the eruption of Mt. Pinatubo have been observed from August to December 1991 over Fort Collins, CO (40.6° N, 105° W), showing a clear increasing trend in stratospheric aerosol activities. These aerosol layers are characterized by the backscatter-ratio profile at 589 nm for altitudes from 12 km to 40 km.On leave from: Department of Radioelectronics, Peking University, Beijing, P.R. China     

Measurements of aerosol distribution by an elastic-backscatter lidar in summer 2008 in Beijing

Elastic lidar observations of profiles of the aerosol extinction, backscattering coefficients, and the lidar ratio have been performed in Beijing. The elastic lidar transmitts wavelengths of 532 and 355 nm. The measurement altitude can reach up to 6 km. The similarity of the extinction and baekscattering profiles suggests a close relation between the mean transmission and reflection properties. The lidar ratio on July 22, 2008 varied from 10 to 30 sr with the mean value of 20 sr. The profiles of the aerosol properties indicate the cirrus at 6 km altitude and a well-mixed boundary layer from July 22 to 24, 2008. The detected boundary layer also agrees well with the high and stable ozone concentration obtained from the differential optical absorption spectroscopy （DOAS） system.     

Multiple Andreev reflections revealed by the energy distribution of quasiparticles

We have performed the tunnel spectroscopy of the energy distribution function of quasiparticles in 5-microm-long silver wires connected to superconducting reservoirs biased at different potentials. The distribution function f(E) presents several steps, which are manifestations of multiple Andreev reflections at the NS interfaces. The rounding of the steps is well explained by electron-electron interactions.     

Analysis of variability in laboratory airborne sound insulation determinations

In an investigation of the overall precision of airborne sound insulation determinations in laboratory conditions 10 different samples were measured, according to the general procedure described in ISO 140/III, in an horizontal transmission chamber, with lateral flanking transmission. Measurements were carried out according to a prescribed programme to investigate the repeatability, r, and reproducibility, Re, in the results, within the same laboratory. Two different operators carried out 15 replicates, five per day during three consecutive days. Each operator performed the test under repeatability conditions: that is, using the same instrumentation, without removing the samples and with the environmental conditions kept constant. Between operators, certain parts of the experimental set-up were different: i.e., the measuring samples had been removed and reinstalled and the environmental conditions were slightly different. The statistical parameters, r and Re′, were first obtained for each sample level separately in order to investigate any dependence with level. Successively, in order to get an improvement in precision, an overall factorial variance analysis was carried out for all levels simultaneously. The whole treatment was performed for each third octave frequency band between 100 and 3150 Hz separately, as well as for the weighted apparent reduction index, R′_w.     

Evaluation of the possibilities of detecting ejections of nitrogen oxides by an airborne differential absorption lidar operating in the medium ir spectral region

Using numerical simulation, we evaluated the possibilities of detecting ejections of nitrogen oxides by an airborne differential absorption lidar operating in the medium IR spectral region at converted frequencies of CO- and CO₂-lasers. We present results of calculations of random errors in determining the integrated content of nitrogen oxide and dioxide depending on the amount of ejection and the flight altitude of an airplane. It is shown that the use of frequency-converted CO- and CO₂-laser radiation makes it possible to determine ground-level ejections of nitrogen oxides at a level of 0.01 MPC. Institute of Atmospheric Optics, Siberian Branch of the Russian Academy of Sciences, I Akademicheskii Ave., Tomsk, 634055, Russia; e-mail: oleg@losa.iao.tomsk.ru. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 6, pp. 843–845, November–December, 1999.     

1/2波片对机载激光雷达偏振探测影响的研究

利用平面平行板模型和晶体膜层理论定量分析了1/2波片对机载激光雷达回波信号偏振探测的影响。计算结果表明:当入射光波长为532nm时,1/2石英波片对机载激光雷达回波信号平行分量与垂直分量透过率比值的影响幅度为0.82～1.196,1/2方解石波片对机载激光雷达回波信号的平行分量与垂直分量透过率比值的影响幅度为0.86～1.27;若用1/2石英波片测得的k=1.2,当考虑石英波片对五的影响时,则偏振探测两通道k的真实值应在1.003～1.463之间;若用1/2方解石波片测得的k=1.2,当考虑方解石波片对k的影响时,偏振探测两通道k的真实值应在0.945～1.395之间。由于1/2波片对k的影响,使机载激光雷达反演得到卷云等探测目标的退偏振比有较大的系统误差。     

Analysis of systematic errors of lidar gas analysis in the atmosphere by the differential absorption lidar method

In the present work, systematic errors of lidar gas analysis in the atmosphere by the differential absorption lidar method in the near-and middle-IR ranges of the spectrum are analyzed. It is demonstrated that the systematic errors depend on many factors, including the meteorological parameters and concentrations of the examined gases along the sensing path, instability of the spectral parameters of laser radiation lines, shift of the absorption line centers caused by the air pressure, Doppler broadening of backscattered signals, and other sources of errors. Methods of error minimization in reconstructing lidar profiles of the examined atmospheric gas concentrations are suggested. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 68–73, June, 2008.     

Monitoring of the stratospheric ozone layer by laser radar

Monitoring of the height distribution of atmospheric ozone up to 50 km is being performed with a ground-based lidar system, which has been in operation since October 1982 on the summit of Zugspitze in the German Alps. Daily and monthly averages of the ozone profile are being obtained with high precision. Furthermore, stratospheric aerosol layers, originating from the eruption of El Chichon volcano in Mexico in sping 1982 are being recorded.     

Seasonal variability of cirrus derived from CALIPSO over Beijing depolarization properties lidar measurements in China

The seasonal variability of cirrus depolarization ratio and its altitude at the region of Beijing （39.93°N, 116.43°E, the capital of China） are presented. From the results obtained from the cloud aerosol lidar and infrared pathfinder satellite observations lidar measurements, it appears that the values of depolarization ratio and altitude of cirrus are generally higher in autumn and summer than those in spring and winter, and the cirrus altitude is modulated by the height of tropopause. Additionally, the depolarization ratio tends to linearly vary with the increase of altitude and the decrease of temperature.     

Seasonal variability of cirrus depolarization properties derived from CALIPSO lidar measurements over Beijing in China

<正>The seasonal variability of cirrus depolarization ratio and its altitude at the region of Beijing(39.93°N, 116.43°E,the capital of China) are presented.From the results obtained from the cloud aerosol lidar and infrared pathfinder satellite observations lidar measurements,it appears that the values of depolarization ratio and altitude of cirrus are generally higher in autumn and summer than those in spring and winter, and the cirrus altitude is modulated by the height of tropopause.Additionally,the depolarization ratio tends to linearly vary with the increase of altitude and the decrease of temperature.     

Surface circulation in the Northern Adriatic Sea as revealed by a drifter experiment

Summary Nine-hours-averaged positions from five satellite-tracked drifting buoys were used to map the surface circulation in the Northern Adriatic sea. The velocity and kinetic-energy fields were calculated on a regular (0.1×0.1)^o grid using averaged positions and remapping the obtained field by means of univariate objective analysis techniques. Eddy and mean flow kinetic-energy contributions were also calculated on a (0.1×0.1)^o grid. The main features of the surface circulation agree with other representations. The double eddy regime due to the Po river outflow, which spreads in a typical summer regime and the corresponding low-dynamics coastal regime along the Italian littoral south the Po outlet are rather well resolved.     

Limitations of the heavy-baryon expansion as revealed by a pion-mass dispersion relation

We consider QCD radiative corrections to vector-boson production in hadron collisions. We present the next-to-next-to-leading order (NNLO) result of the hard-collinear coefficient function for the all-order resummation of logarithmically enhanced contributions at small transverse momenta. The coefficient function controls NNLO contributions in resummed calculations at full next-to-next-to-leading logarithmic accuracy. The same coefficient function is used in applications of the subtraction method to perform fully exclusive perturbative calculations up to NNLO.     

On the probability distribution of the stochastic saturation scale in QCD

It was recently noticed that high-energy scattering processes in QCD have a stochastic nature. An event-by-event scattering amplitude is characterised by a saturation scale which is a random variable. The statistical ensemble of saturation scales formed with all the events is distributed according to a probability law whose cumulants have been recently computed. In this work, we obtain the probability distribution from the cumulants. We prove that it can be considered as Gaussian over a large domain that we specify and our results are confirmed by numerical simulations.