沿岸熏烟扩散的中尺度模拟系统

建立了一个沿岸熏扩散的中尺度模拟系统，它由一个二维二阶矩闭合的ＰＢＬ模式和一个随机流动扩散模式组成。初步的模拟和一些数值试验结果表明，随机游动扩散模式与现行的基于高斯扩散公式的熏烟扩散模式比较，其物理模型更为合理；采用二阶矩湍流闭合方案的ＰＢＬ模式能模拟得到合理的热力内边界层（ＴＩＢＬ）结构特征，将二阶矩湍流闭合ＰＢＬ模式模拟所得气象场作为随机游动扩散模式的气象输入，可以较好地预测沿岸地区日间持续     

合肥地震台地下电性层研究

本文介绍在合肥台地电布极区进行十字电测深的勘选测量方法,根据电测深数据反演观测场地地下介质电性结构,就多解性问题进行了讨论。     

Turbulence closure models and their application in RAMS

Turbulence closures are fundamental for modelling the atmospheric diffusion in numerical codes and the resulting eddy diffusivities are key parameters in describing the transport and dispersion in the boundary layer. In this work, four turbulence closure schemes have been applied for reproducing a neutral flow over schematic complex terrain using the meteorological model RAMS. Two of the closures, a one-equation (E-l) and a two-equations (E-) model, have been implemented in RAMS in alternative to the ones originally available. In these cases, an analytical method based on the similarity theory for the atmospheric surface layer and boundary layer is adopted to calculate the empirical constants of the turbulence closures. Some examples of numerical studies performed to simulate the flow and turbulence over a 3-D hill in wind-tunnel experiment in neutral stratification are presented and discussed. An intercomparison of simulations related to different closures is considered by analysing the main features of the flow over the hill and by comparing calculated vertical profiles of turbulent kinetic energy with measured ones.     

Comparison of dynamic subgrid-scale models for simulations of neutrally buoyant shear-driven atmospheric boundary layer flows

Several non-dynamic, scale-invariant, and scale-dependent dynamic subgrid-scale (SGS) models are utilized in large-eddy simulations of shear-driven neutral atmospheric boundary layer (ABL) flows. The popular Smagorinsky closure and an alternative closure based on Kolmogorov’s scaling hypothesis are used as SGS base models. Our results show that, in the context of neutral ABL regime, the dynamic modeling approach is extremely useful, and reproduces several establised results (e.g., the surface layer similarity theory) with fidelity. The scale-dependence framework, in general, improves the near-surface statistics from the Smagorinsky model-based simulations. We also note that the local averaging-based dynamic SGS models perform significantly better than their planar averaging-based counterparts. Lastly, we find more or less consistent superiority of the Smagorinsky-based SGS models (over the corresponding Kolmogorov’s scaling hypothesis-based SGS models) for predicting the inertial range scaling of spectra.     

超细粉尘的扬尘机理研究

针对目前对于一般尘源控制研究较少,而系统研究粉尘的扬尘(尘化)机理的研究就更少这一状况,提出弄清尘化机理、从源头上控制是治理粉尘的首要问题,对粉尘颗粒作用力进行分析,特别就超细粉尘的扬尘机理提出相应的物理模型并进行初步研究.图1,参2.     

Observations of the cross-wind velocity variance in the stable boundary layer

Nine tower datasets over grassland, brush rangeland, snow covered plain, the ocean, three different pine forests, an aspen forest and an urban site, are used to document the scale-dependence of the cross-wind velocity variance in the stable boundary layer. The turbulence velocity variance scales with the surface momentum flux, as reported in previous studies. Such scaling removes the stability dependence of the variance at a given site, and also removes most of the differences between sites. The scaling is more effective with use of a record-dependent averaging time for defining the turbulent fluctuations. The variable averaging time is the timescale associated with the gap region in the heat flux multiresolution cospectra. On scales larger than turbulence and less than a few hours (mesoscale), variations in the cross-wind velocity variance at a given site are not related to local variables such as the friction velocity. Possible exceptions include suppression of turbulence and mesoscale motions in well-defined drainage flows and enhancement of turbulence and mesoscale motions in stronger winds downstream of a ridge. Larger mesoscale variance is associated with complex terrain and forested sites compared to the more homogeneous sites in flat terrain with short or no vegetation. These differences between sites are related to the absence of a gap region in the velocity spectra at the complex terrain and forested sites. The observed probability distribution functions of the total variance and the mesoscale variance are documented for different averaging times, stability classes and site characteristics.     

臭氧层减少对沿海地区大气温度与环境的影响

利用青岛市连９年的主空探测资料，分析也大气温度的变化与高空臭氧层有关，高层气温与地面气温呈负相关变化。高空臭氧减少，使沿海地区温度梯度加大，在不我向时可能造成大气污染加重，暖气团辐合上升，易将大气污染物挟带支支中，当酸性物大于碱性物时形成酸雨，产生一系大气环境问题。     

塔克拉玛干沙漠北部全新世环境演变（Ⅰ）

通过对塔克拉玛干沙漠北部，塔里木河泛滥平原典型剖面的沉积物粒度特征、化学元素的变化和沉积相特征的研究，并结合~（１４）Ｃ测年，揭示了本区域全新世以来的环境变化规律，本区全新世以来的多风、高温、干燥的气候形成是以全球气候波动为背景，叠加内陆干旱封闭盆地影响而成的。但在干燥气候条件下曾有过几次空气湿度较大的偏湿期。本区沉积相主要以河流冲积作用形成的粘土层和风力作用下形成的风砂层为主，剖面中的亚粘土与现代河流相特征一致，剖面中风砂土与现代流沙性质趋同。全新世以来本区共发生３次明显的河流泛滥期，可以同全新世以来的间冰期对应。     

一种计算粒子电迁移率的新模型

近几年来,粒子电迁移率引起了更多学者的注意。因为它是表征带电粒子在电场中运动的重要参数之一。在这方面,人们已作了大量的研究工作,提出了一些计算粒子电迁移率的理论和半经验模型。基于前人的研究,本文提出了一种计算粒子电迁移率的新模型,并用前人的实验结果和本研究的实验结果对此模型进行了检验。计算结果和实验数据很吻合。就某种意义上讲,此模型是对以前模型的扩展和改进,它可广泛应用于溶胶的研究和工业应用。