光化学臭氧日变化特征与其前体物关系的探讨   总被引：18，自引：2，他引：18  

朱彬  安俊岭  王自发  李一 《南京气象学院学报》2006,29(6):744-749

应用大气光化学模式研究了日最大臭氧体积分数及其出现时刻与其前体物NMHC、NOx体积分数及NMHC／NOx比值的关系。结果表明，影响日最大臭氧体积分数（ψ03max）脊线位置（EKMA图，Empirical Kinetic Modeling Approach）的关键因子是NMHC成份组成比例；日臭氧体积分数达到最大值需要的时间（τ03max）与NMHC／NOx比值及NMHC成份组成比例有关，与NMHC、NOx体积分数关系不大。此外，利用该结果解释了近20a北京日最大臭氧体积分数出现时刻具有不断提前的变化趋势的原因。  相似文献   

多波束水深测量与海洋重磁测量的综合实施     

董庆亮方兆宝  赵培海 《测绘科学与工程》2006,26(4):37-40

随着对海洋测量信息量需求的增多，海洋综合性测量越来越受到重视。本文介绍了利用EM120型多波束测深系统、S-121型海洋重力仪、G-880型海洋磁力仪和650MK2型声速剖，面仪同步进行海洋重力、海洋磁力和全覆盖水深综合测量的方法和经验，论述了综合测量中应该注意的一些问题。  相似文献   

Application and Study of Precipitation Schemes in Weather Simulation in Summer and Winter over China          下载免费PDF全文

XU Guoqiang  WAN Qilin  HUANG Liping  XUE Jishan  CHEN Dehui 《Acta Meteorologica Sinica》2006,20(1):28-38

Through simulation of summer and winter precipitation cases in China, the cloud precipitation schemes of model were examined. Results indicate that it is discrepant between convective precipitation simulated by the Kain-Fritsch (KF) scheme and Betts-Miller (BM) scheme in summer, the former scheme is better than the latter in this case. The ambient atmosphere may be varied by different convective schemes. The air is wetter and the updraft is stronger in the KF scheme than in the BM scheme, which can induce the more grid scale precipitation in the KF scheme, i.e., the different cumulus schemes may have the different and important effect on the grid scale precipitation. However, there is almost no convective rain in winter in northern China, so the effect of cumulus precipitation on the grid scale precipitation can be disregarded. Therefore, the gird scale precipitation is primary in the winter of northern China.  相似文献   

Kinematic parameters of young subsystems and the galactic rotation curve     

M. V. Zabolotskikh  A. S. Rastorguev  A. K. Dambis 《Astronomy Letters》2002,28(7):454-464

We analyze the space velocities of blue supergiants, long-period Cepheids, and young open star clusters (OSCs), as well as the H I and H II radial-velocity fields by the maximum-likelihood method. The distance scales of the objects are matched both by comparing the first derivatives of the angular velocity Ω′ determined separately from radial velocities and proper motions and by the statistical-parallax method. The former method yields a short distance scale (for R₀=7.5 kpc, the assumed distances should be increased by 4%), whereas the latter method yields a long distance scale (for R₀=8.5 kpc, the assumed distances should be increased by 16%). We cannot choose between these two methods. Similarly, the distance scale of blue supergiants should be shortened by 9% and lengthened by 3%, respectively. The H II distance scale is matched with the distance scale of Cepheids and OSCs by comparing the derivatives Ω′ determined for H II from radial velocities and for Cepheids and OSCs from space velocities. As a result, the distances to H II regions should be increased by 5% in the short distance scale. We constructed the Galactic rotation curve in the Galactocentric distance range 2–14 kpc from the radial velocities of all objects with allowance for the difference between the residual-velocity distributions. The axial ratio of the Cepheid+OSC velocity ellipsoid is well described by the Lindblad relation, while σ_u≈σ_v for gas. The following rotation-curve parameters were obtained: Ω₀=(27.5±1.4) km s^?1 kpc^?1 and A=(17.1±0.5) km s^?1 kpc^?1 for the short distance scale (R₀=7.5 kpc); and Ω₀=(26.6±1.4) km s^?1 kpc^?1 and A=(15.4±0.5) km s^?1 kpc^?1 for the long distance scale (R₀=8.5 kpc). We propose a new method for determining the angular velocity Ω₀ from stellar radial velocities alone by using the Lindblad relation. Good agreement between the inferred Ω₀ and our calculations based on space velocities suggests that the Lindblad relation holds throughout the entire sample volume. Our analysis of the heliocentric velocities for samples of young objects reveals noticeable streaming motions (with a velocity lag of ～7 km s^?1 relative to the LSR), whereas a direct computation of the perturbation amplitudes in terms of the linear density-wave theory yields a small amplitude for the tangential perturbations.  相似文献   

光电测距仪的乘常数问题     

张学庄 《武汉大学学报(信息科学版)》2002,27(6):611-615

讨论了光电测距仪的乘常数问题,并举出了按光电测距仪检定规程（试行）JJG703－90检测得到的乘常数（R）不正确的例子,分析了R误差大的原因。  相似文献   

太阳活动百年尺度的跃变与气候跃变的相关分析   总被引：10，自引：5，他引：5  

冯松  汤懋苍 《高原气象》1998,17(3):266-270

讨论了２５００多年来太阳黑子周期长度（ＳＣＬ）的跃变特征,发现有在年尺度上ＳＣＬ基本在平均值附近变化,而其变率则存在明显的跃变现象,当ＳＣＬ的变率增大时,气候随之发生冷跃变,反之,则发生暖跃变。小冰期内,太阳活动弱且不稳定,与地球气候冷且不稳定具有同时性。  相似文献   

小波分析在大气边界层结构研究中的应用实例     

孙爱东  徐玉貌 《南京气象学院学报》1998,21(4):696-702

将小波分析的方法应用于大气边界层风、温场结构的研究,表明了这种方法应用于大气边界层研究的优越性。小波分析方法与谱分析方法,多尺度分析方法可以互补。当研究不同尺度湍流的串级过程和突变气象场的位置时,小波方法更为优越。  相似文献   

不同下垫面的大气边界层湍流扩散特征          下载免费PDF全文

赵志强  郑乃廷 《应用气象学报》1998,9(4):478-484

利用海洋、戈壁、城郊和城市4种不同下垫面上的湍流观测资料,运用多尺度湍流概念和方法计算分析了风速谱和扩散参数等湍流特征量。结果表明:下垫面的粗糙度对大气边界层湍流特征影响很大,随着粗糙度的增大,速度谱的峰值频率向高频方向移动,扩散参数增大。  相似文献   

尺度参数的Lp估计与精度评定   总被引：3，自引：0，他引：3  

周世健  陈永奇  邓康伟 《测绘学报》1998,27(4):300-307

根据定位参数与尺度参数的联合Ｍ估计,导出了尺度参数的Ｌｐ估计;当ｐ＝２时,与最小二乘估计一致,观测数据服从正态分布时,为最优无偏估计;由于尺度参数Ｌｐ估计的影响函数为无界函数,估计不具抗差性,但把残差Ｗｉｎｓｏｒ化,作者得到了尺度参数的抗差Ｌｐ估计;依据定位参数的协方差阵,可进行Ｌｐ估计的精度评定。这些结果对于Ｌｐ估计的研究和应用具有一定的参考价值。  相似文献   

像素图数学基础变换方法研究     

杨玉彬  杨启和 《测绘学院学报》1998,(2)

针对像素图数学基础变换问题 ,提出了一种间接变换思路 ,给出了具体的变换方法 ,包括整块变换和分块变换及拼接等问题 ,并作了相关的实验。  相似文献