低Peclet数下剪切流中气溶胶粒子的传质率     

温景嵩  曾庆存  王永光 《大气科学》1994,18(1):105-112

本文研究了低Péclet数下剪切流中气溶胶粒子的传质率。Péclet数(Pe)是物质浓度的对流输送项对分子扩散项的比。它等于Reynolds数(Re)与Schmidt数的(Sc)之积。本文应用奇异扰动方法得到了无因次传质率Nu(Nusselt数)在小Péclet数条件下的四项渐近展式，因而?改进了前人的结果。  相似文献   

The impact of high altitude aircraft on the ozone layer in the stratosphere     

Xue Xi Tie  Guy Brasseur  Xing Lin  Pierre Friedlingstein  Claire Granier  Philip Rasch 《Journal of Atmospheric Chemistry》1994,18(2):103-128

The paper discusses the potential effects on the ozone layer of gases released by the engines of proposed high altitude supersonic aircraft. The major problem arises from the emissions of nitrogen oxides which have the potential to destroy significant quantities of ozone in the stratosphere. The magnitude of the perturbation is highly dependent on the cruise altitude of the aircraft. Furthermore, the depletion of ozone is substantially reduced when heterogeneous conversion of nitrogen oxides into nitric acid on sulfate aerosol particles is taken into account in the calculation. The sensitivity of the aerosol load on stratospheric ozone is investigated. First, the model indicates that the aerosol load induced by the SO₂ released by aircraft is increased by about 10–20% above the background aerosols at mid-high latitude of the Northern Hemisphere at 15 km for the NASA emission scenario A (the NASA emission scenarios are explained in Tables I to III). This increase in aerosol has small effects on stratospheric ozone. Second, when the aerosol load is increased following a volcanic eruption similar to the eruption of El Chichon (Mexico, April 1982), the ozone column in spring increases by as much as 9% in response to the injection of NO _x from the aircraft with the NASA emission scenario A. Finally, the modeled suggests that significant ozone depletion could result from the formation of additional polar stratospheric clouds produced by the injection of H₂O and HNO₃ by the aircraft engines.  相似文献   

BALLOON-BORNE MEASUREMENTS OF AEROSOL VERTICAL DISTRIBUTIONS OVER BEIJING DURING THE SUMMER AND AUTUMN OF 1993          下载免费PDF全文

Zhou Jun  Tan Kun  Shao Shisheng  Gong Zhiben  Shi Guangyu  Guo Jiandong  Wang Biao  Zhang Baowu  Sun Baolai  Yasunobu Iwasak  Masahiko Hayashi  Masahiro Hase 《Acta Meteorologica Sinica》1994,8(4):478-487

The results of two balloon soundings during the summer and autumn of 1993 from the Xianghe Observation Station are being utilized in a study of the temporal and spatial distribution of the atmospheric aerosols.The balloon,gondola,instrumentation and atmospheric conditions during the observation period are described.The temporal and spatial characteristics of aerosol concentration,size ratio,mixing ratio,and size distribution for both troposphere and strato-sphere are presented and analyzed.  相似文献   

冀北侏罗系上统火山岩中宇宙尘的发现及其地质意义     

蔡开运  史中华 《现代地质》1994,8(3):273-280,T002

在冀北丰宁、沽源、赤城一带的上侏罗统火山岩中发现有不同形态的铁质及玻璃质微球粒。经电镜扫描及外貌结构构造的鉴定，显示有熔融、碰撞、逸气、旋纹、冷疑、收缩等特征；经电子探针及Ｘ射线粉晶衍射分析，认为是宇宙尘。对其进行研究不仅有重要的地质意义，而且有找矿意义。  相似文献   

NOAA WP-3D instrumentation and flight operations on AGASP-II     

R. C. Schnell  T. B. Watson  B. A. Bodhaine 《Journal of Atmospheric Chemistry》1989,9(1-3):3-16

The second Arctic Gas and Aerosol Sampling Program (AGASP-II) was conducted across the non-Soviet Arctic in March and April 1986, to study the aerosol, gaseous, chemical, and optical properties of Arctic haze. One component of the program was supported with an instrumented NOAA WP-3D atmospheric research aircraft. Measurements of wind, temperature, ozone, water vapor, condensation nucleus concentration, and aerosol scattering extinction coefficient were used to determine the locations and properties of haze layers. The first three NOAA WP-3D research flights were conducted north of Barrow, Alaska, and over the Beaufort Sea northeast of Barter Island, Alaska. The next three sampled conditions in the high Arctic near Alert, Northwest Territories, Canada. All basic meteorological, gas, and aerosol systems are described. The WP-3D flight tracks and operations are presented.  相似文献   

Interpretation of Mauna Loa atmospheric transmission relative to aerosols,using photometric precipitable water amouts     

Ellsworth G. Dutton  John J. Deluisi  P. Arne 《Journal of Atmospheric Chemistry》1985,3(1):53-68

Precipitable water measurements made coincident in time and space with direct broadband solar irradiance measurements are used in conjunction with an atmospheric transmission model to derive a parameter whose major dependence is on total aerosol extinction. Irradiance measurements are used to calculate an atmospheric transmission factor (ATF) that is independent of the instrument calibration and the extraterrestrial solar constant. The dependency of the ATF on precipitable water is determined using LOWTRAN5, an atmospheric transmission model with high spectral resolution. Precipitable water measurements are then used to adjust the measured ATF to correspond to an ATF value obtained for a constant precipitable water amount. The remaining variability in the adjusted ATF is due mostly to aerosol extinction. The technique is applied to a 6-year period (1978–1983) for clear-sky mornings at Mauna Loa, Hawaii (MLO). MLO ATF aerosol residuals are compared with independently measured monochromatic aerosol optical depth. Results show that the ATF aerosol residual is nearly equal to the 500 nm aerosol optical depth prior to the eruption of E1 Chichon, at which time a nonlinear time-dependent relationship between the two quantities is evident. ATF aerosol residuals reflect the spectrally integrated aerosol influence on transmission and, therefore, could indicate better than monochromatic optical depth the radiation balance perturbations due to aerosols. The 6-year precipitable water record for MLO, determined from a dual-channel sunphotometer, has a mean value of 0.3 cm. An annual cycle in precipitable water is evident, as is a 4-month 5-standard-deviation drought from December 1982 through March 1983.  相似文献   

齐依求金矿中微球粒特征     

王之峰  马生明 《黄金地质》1995,1(2):76-79,T001

首次报道齐依求金矿中微球粒的发现，对微球粒形态特征、表面及断面结构、物理特性、矿物组成、化学成分进行分析测试，并就其成因作了初步探讨，认为属宇宙成因。  相似文献   

大气气溶胶中NO￣－＿3、SO￣（2－）＿4研究     

李忠勤  姚檀栋  谢自楚 《地球科学进展》1995,(3)

根据对国内外有关文献资料的总结归纳，对气溶胶中　、　的研究现状及其在不同类型样品中的浓度量值分别进行了阐述；对雪冰层中的　和　进行了本底划分，并对这些本底的来源、组成及特征进行了分析。  相似文献   

从全波段太阳直射辐射确定大气气溶胶光学厚度 II：实验研究   总被引：2，自引：1，他引：2       下载免费PDF全文

邱金桓  杨景梅  潘继东 《大气科学》1995,19(5):586-596

本文通过比较太阳直射表和太阳光度计探测的大气柱气溶胶光学厚度，分析了从太阳直射表探测的全波段太阳直射光强信息确定大气柱气溶胶光学厚度的误差，并应用北京观象台的太阳直射表观测资料，反演得到了 1990—1993年北京大气柱气溶胶光学厚度，分析了该光学厚度月与年变化规律以及1991年菲律宾皮纳图博火山爆发对北京大气气溶胶含量的影响。本文还提出了关于有效水汽含量的一个经验关系式，用于确定水汽对太阳辐射的吸收率。  相似文献   

Aerosol concentrations and size distribution in the troposphere and lower stratosphere over Thumba     

B. H. Subbaraya  A. Jayaraman 《Pure and Applied Geophysics》1982,120(3):407-421

Rocket-borne ultraviolet photometers operating at =0.31 m have been used at Thumba (8°33N, 76°52E) to make measurements of atmospheric scattering at tropospheric and lower stratospheric altitudes. Measurements could be made of the amplitude of the scattered fluxes and the angular distribution up to an altitude of about 24 km on three rocket flights conducted as part of the 16 February 1980 solar eclipse campaign. These measurements have been used to study the size distribution as well as the number densities of aerosols in the troposphere and lower stratosphere over Thumba.  相似文献