APPLICATION OF BDA SCHEME IN TYPHOON TRACK PREDICTION

The MM5, which is the PSU/NCAR mesoscale nonhydrostatic limited-area model, and its adjoining modeling system are used in this paper. Taking T106 analysis data as background field the authors generate an optimal initial condition of a typhoon by using two bogus data assimilation schemes, and conduct some numerical simulating experiments. The results of No.9608 typhoon (Gloria) show that the optimal initial field have some dramatic improvements, such as inaccurate position of typhoon center, weaker typhoon circulation and incomplete inner structure of the typhoon, which are caused by shortage of data over the sea. Some improvements have been made in the track forecast. Through several comparing experiments, the initialization optimized by BDA scheme is found to be more reasonable than GFDL scheme and its typhoon track forecast is better.     

Evaluation of the Urban Tile in MOSES using Surface Energy Balance Observations

The UK Met Office has introduced a new scheme for its urban tile in MOSES 2.2 (Met Office Surface Exchange Scheme version 2.2), which is currently implemented within the operational Met Office weather forecasting model. Here, the performance of the urban tile is evaluated in two urban areas: the historic core of downtown Mexico City and a light industrial site in Vancouver, Canada. The sites differ in terms of building structures and mean building heights. In both cases vegetation cover is less than 5%. The evaluation is based on surface energy balance flux measurements conducted at approximately the blending height, which is the location where the surface scheme passes flux data into the atmospheric model. At both sites, MOSES 2.2 correctly simulates the net radiation, but there are discrepancies in the partitioning of turbulent and storage heat fluxes between predicted and observed values. Of the turbulent fluxes, latent heat fluxes were underpredicted by about one order of magnitude. Multiple model runs revealed MOSES 2.2 to be sensitive to changes in the canopy heat storage and in the ratio between the aerodynamic roughness length and that for heat transfer (temperature). Model performance was optimum with heat capacity values smaller than those generally considered for these sites. The results suggest that the current scheme is probably too simple, and that improvements may be obtained by increasing the complexity of the model.     

北京市大兴区地下水资源开采潜力分析

本文根据不同含水岩组的水量、水质和水温特征,分析了大兴区地下水资源的开采潜力,提出了地下水开发利用建议,为大兴区城市规划、城市供水方案提供依据。     

万丰路桥大吨位矩形截面桩成孔施工技术

针对在卵石及基岩地层中桩孔施工时成孔难、渗漏大的问题，以液压抓斗为成孔设备，采用合理的机械结构、钻进方法、泥浆配方进行矩形截面桩的施工。     

李家峪储灰库粉煤灰水渗漏治理措施研究

以河北省唐山市陡河电厂李家峪储灰场为例，利用火力发电厂排出的粉煤灰自身较好的防渗性能，结合储灰库区渗漏途径和渗漏段的分布，沿库区周边分期、分段进行针对性排灰，并根据地下水动态监测结果适时调整，使库区周围地下水环境逐步得到改善，得出周边排灰在山区储灰库防渗中具有可行性，其成本低效果显著值得在山区储灰库的防渗工作中推广。     

加拿大McArthur River铀矿床成矿特点及在我国寻找相同类型铀矿床的几点认识

加拿大萨斯喀彻温省西北部阿萨巴斯卡盆地McArthur River铀矿床是世界上最大、最富的不整合面型铀矿床。笔者通过对该矿床的剖析，从宏观上对这类铀矿床的一些形成规律进行了初步探讨，并对在我国寻找不整合面型或相似类型的铀矿床提出了一些认识。     

水库渗流影响文物遗址安全发掘研究——以湖南里耶秦代古城遗址为例

与古遗址相邻的江、河由于后期的工程活动,如水库、大坝的修建和蓄水,水位上升,将对遗址区地下水的运动规律及渗流场产生较大影响。在其影响下,古遗址可能产生各种环境地质灾害并对其发掘安全产生不利影响。论文以国家重点文物——湖南里耶秦代古城遗址安全发掘深度研究为例,在分析水库蓄水诱发的环境地质灾害的基础上,对遗址在不同库水位下的安全发掘深度及发掘方案进行了研究,提出了保障发掘安全的工程措施。研究成果为国家重点文物的保护和进一步发掘提供了科学依据。对类似文物工程的保护和发掘具有借鉴意义。     

中国太古宙

根据最近10多年来中国太古宙岩石同位素地质年代学新数据和中国太古宙岩石三个主要分布地区冀东、辽东和吉林南部、太行山-五台山的时间-地层图及其对比情况,认为尚无足够的证据支持中国太古宙四分,三分方案更适合于中国太古宙的情况：约2．9Ga可以作为晚、中太古代的界线,而3.5Ga作为中、早太古代界线尚不很明晰。     

The numerical simulation on the PBL structure and its evolution over small-scale concave terrain

A high-resolution, nonhydrostatic, three-dimensional diagnostic PBL model over small-scale concave terrain was established in this paper. A two-dimensional prognostic model was developed based on the diagnostic model. The hydrostatic approximation was abandoned and the simple energy (E-ε) closure scheme was used in both mod-els. Using the two models, characteristics of PBL structure and its evolution were fully studied. The main characteris-tic of the PBL is the circulation, and it fairly affects the distribution of the pollutant in the pit.     

大气动力学方程组的定性理论及其应用

基于完整的湿大气动力学方程组,利用无穷维动力系统的新理论和新方法,系统讨论了强迫耗散的非线性大气系统的定性理论及其应用。将完整的强迫耗散非线性湿大气动力学方程组化为Hilbert空间中一个等价的算子方程,研究了算子的性质及其物理意义,在此基础上得到湿大气系统全局吸引子的存在性定理,揭示出系统向外源的非线性适应特征,并把结果推广到有地形动力作用和非定常外源强迫的情形。同时探讨了大气方程组惯性流形的存在,大气多平衡态产生的根源以及强迫、耗散和非线性对系统解的渐近行为的影响。在理论结果的基础上,提出强迫耗散的非线性动力系统中存在三类时间边界层、方程组简化准则、分解算法的算子约束原则以及支撑吸引子基底的少数自由度的构造方法,探讨了理论在非线性发展方程差分格式的设计和计算稳定性分析、多平衡态的数值分析、数值模式延伸预报的改进、短期气候预测以及一类中尺度系统分析与预测中的应用,指出描述长期过程动力学模式的必备条件,给出初值与模式相协调的合理解释。最后,对今后的研究方向作了展望。