试论地质资料档案的保密与开发利用

地质资料作为一种特殊商品,具有公益性和商业性两重属性。地质资料具有其商品属性,在市场经济条件下,价值意义重大。在分析了几种主要的泄密形式后,提出了地质资料档案的保密原则及措施。但是地质档案资料的价值在于开发利用,新形势下进一步加强地质档案资料的科学管理,维护档案资料所有者的合法权益,有效开发利用馆藏地质资料,实现其应有的价值,为国民经济发展服务,是地质资料档案管理工作者的光荣和艰巨的使命。     

江苏夏季逐月高温日数与西太平洋海温场相关分析及预测模型建立

夏季高温的发生是多个因子共同作用的综合反映,其中大气环流背景对高温的出现起到重要作用,而根据海气相互作用的研究,海温变化和大气环流之间有一定相关关系,决定了海温对陆上温度具有一定的可预报性。基于此原理基础,本文利用1978—2007年30年西太平洋海温和江苏各区域的高温日数资料,运用区域平均方法、场相关分析法,探讨了与江苏不同地区区域平均高温日数相关的强信号海区,分析了利用海温进行逐月高温日数预报的可能性。然后运用最优化相关处理技术将西太平洋海温作为长期预报因子,建立了江苏不同区域夏季逐月高温日数长期预测模型,模型均通过了α=0.01显著性水平检验,拟合效果理想,同时并进行了实际预报试验,预报效果较好,可以投入业务使用。此研究对江苏高温的长期预报及高温灾害服务具有重要指导意义。     

Experimental investigation of internal tides generated by finite-height topography

Internal tides generated by finite-height topography are investigated in the laboratory, and the particle image velocimetry (PIV) technique is applied to measure the velocity fields. The energy, energy flux, and vertical mode structure of the internal tides are calculated and analyzed. The experimental results indicate that the strength of the wave field is mainly affected by the normalized topography height. The rays radiated from the taller topography are wider than those radiated from the lower topography. Both the experimental and theoretical results indicate that the normalized energy and energy flux of the internal tides are mainly determined by the normalized topography height, and the increase of the two quantities follows a quadratic function, and they almost remain unchanged with different normalized frequencies except for higher frequency. The percentage of energy for mode-1 and mode-2 internal tides is determined not only by frequency but also by topography height. In addition, an “inherent normalized frequency” is observed in the experiment, at which the percentage of energy for mode 1 and mode 2 does not vary with topography height. The decay rate of internal tide energy in the near field and far field is also estimated, with average values of 36.5 and 7.5%, respectively.     

Density Perturbation and Energy Flux of Internal Waves from Velocity Data

Internal waves play a crucial role in ocean mixing, and density perturbation and energy flux are essential quantities to investigate the generation and propagation of internal waves. This paper presents a methodology for calculating density perturbation and energy flux of internal waves only using a velocity field that is based on linearized equations for internal waves. The method was tested by numerical simulations of internal waves generated by tidal flowing over a Gaussian topography in a stratified fluid. The density perturbations and energy fluxes determined using our method that only used velocity data agreed with density perturbations and energy fluxes determined by the equation of state based on temperature data. The mean relative error (MRE) and root mean square error (RMSE) between the two methods were lower than 5% and 10% respectively. In addition, an experiment was performed to exam our method using the velocity field measured by Particle Image Velocimetry (PIV), and the setup of the experiment is consistent with the numerical model. The results of the experiments calculated by the methods using PIV data were also generally equal to those of the numerical model.