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41.
作者使用 NCEP/ NCAR再分析资料 ,在热带 30°S~ 30°N纬带用谐波分析方法分离出超长波之后 ,再采用环流诊断方法 ,发现南海季风区存在地域性环流系统。文中给出冬、夏季风期该系统的三维空间结构和相应的热源分布 ,讨论了该地域性环流系统对南海季风气候及其异常的作用 ,并探讨夏季风爆发北部先于南部的一种可能的气候原因。 相似文献
42.
大气折射延迟是空间大地测量中的一个主要误差源。本文严格地给出了中性大气路径弯曲改正的原理性公式。通过对各种因素量级的分析,在亚毫米量级的精度上给出了一个以视天顶距正切和正割乘积为参数的级数展开模型。新模型在球对称大气模型下,级数展开模型的精度达到了毫米量级,理论上可以展开到任意阶次,且可允许观测高度角小到5°。 相似文献
43.
直流输电线路对磁测的影响 总被引:3,自引:0,他引:3
越来越多的远距离、大容量直流输电线路投入运行对线路附近地区的磁测工作产生了不可忽视的影响。本文阐述了直流输电线路的结构、线路磁场特征及对以地质找矿为目的的磁测工作的影响。对直流输电线路磁场在磁测图中的特点也做了讨论,列举了直流输电线路影响的实例。 相似文献
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Observations of whistlers during quiet times made at low-latitude ground station Nainital (geomag. lat. 19 1 N) are used to deduce plasmasphere-ionosphere coupling fluxes. The whistler data from 3 magnetically quiet days are presented that show a smooth decrease in dispersion with time. This decrease in dispersion is interpreted in terms of a corresponding decrease in electron content of tubes of ionization. The electron densities, electron tube contents (1016 el/m2-tube) and coupling fluxes (10 el m–1 s–2) are computed by means of an accurate curve fitting method developed by Tarcsai (1975) and are in good agreement with the results reported by other workers. 相似文献
47.
The purpose of this paper is to find correlation between OI 6300 Å line intensity with solar and ionospheric parameters. A critical study have been made and the following important results are obtained:
相似文献
(i) | Solar flare index plays more important role for the emissions of 6300 Å line than other solar parameters. |
(ii) | Intensity of 6300 Å line increases linearly with the increase of solar flare index. |
(iii) | Virtual height plays more important role than critical frequency for the emission of 6300 Å line-intensity. |
(iv) | Possible explanation of this type of variation is also presented. |
48.
Chantal Guillard Hervé Delprat Can Hoang-van Pierre Pichat 《Journal of Atmospheric Chemistry》1993,16(1):47-59
The photodegradation of naphthalene (NPH), chosen as a model of polynuclear aromatic pollutants, has been studied in the presence of a layer of four water-insoluble inorganic solids which can be found in the troposphere (TiO2, Fe2O3, muscovite, and a fly ash sample). Direct photolysis of NPH is negligible at >340 nm. Dark adsorption of NPH on TiO2 (mainly anatase, nonporous, 50 m2 g–1) at 293 K corresponds to a surface coverage ofca. 50% at equilibrium. Under these conditions (saturated surface), the stationary-state photocatalytic degradation reaches 0.4 molecule nm–2 h–1 (>340 nm, radiant fluxca. 22 mW cm–2). Dioxygen is required and its partial pressure in air is such that the degradation is zero order in O2. Water vapor markedly increases the rate. The other particulates have also an effect, less important than that of TiO2, however quite noticeable with respect to surface area unit for the fly ash sample which contains 3.2% Fe2O3. Apart from 1,4-naphthoquinone, which is the main intermediate product in all cases, 2-naphthol, phthalide, phthaldialdehyde, phthalic acid, acetophenone, benzaldehyde, benzoic acid are also formed on dry TiO2. Depending on their volatility, these compounds are transferred to the gas phase or remain principally adsorbed on the solid particles where they are further transformed. For instance, phthalic acid (or anhydride) and benzoic acid are generated from 1,4-naphthoquinone. Degradation mechanisms are briefly discussed. 相似文献
49.
The existence of a suspected geological fault has been confirmed using Solid State Nuclear Track Detectors (SSNTDs) by measuring radon concentration variations in the upper soil above its inferred position. The results obtained prompted us to increase the natural radon signal in the soil, using an additional radon source; this enhancement technique, has been experimentally checked with SSNTD detectors.On leave from Faculté des Sciences, Laboratoire des D.S.T.N. Université de Dakar, Dakar-Fann, Sénégal 相似文献
50.
Daily measurements of atmospheric concentrations of dimethylsulfide (DMS) were carried out for two years in a marine site at remote area: the Amsterdam Island (37°50S–77°31E) located in the southern Indian Ocean. DMS concentrations were also measured in seawater. A seasonal variation is observed for both DMS in the atmosphere and in the sea-surface. The monthly averages of DMS concentrations in the surface coastal seawater and in the atmosphere ranged, respectively, from 0.3 to 2.0 nmol l-1 and from 1.4 to 11.3 nmol m-3 (34 to 274 pptv), with the highest values in summer. The monthly variation of sea-to-air flux of DMS from the southern Indian Ocean ranges from 0.7 to 4.4 mol m-2 d-1. A factor of 2.3 is observed between summer and winter with mean DMS fluxes of 3.0 and 1.3 mol m-2 d-1, respectively. 相似文献