Impact of Different Aerosols on the Evolution of the Atmospheric Boundary Layer

The present work analyzes the effect of aerosols on the evolution of the atmospheric boundary layer (ABL) over Shangdianzi in Beijing.A one-dimensional ABL model and a radiative transfer scheme are incorporated to develop the structure of the ABL.The diurnal variation of the atmospheric radiative budget,atmospheric heating rate,sensible and latent heat fluxes,surface and the 2 m air temperatures as well as the ABL height,and its perturbations due to the aerosols with different single-scattering albedo (SSA) are studied by comparing the aerosol-laden atmosphere to the clean atmosphere.The results show that the absorbing aerosols cause less reduction in surface evaporation relative to that by scatting aerosols,and both surface temperature and 2 m temperature decrease from the clean atmosphere to the aerosol-laden atmosphere.The greater the aerosol absorption,the more stable the surface layer.After 12:00 am,the 2 m temperature increases for strong absorption aerosols.In the meantime,there is a slight decrease in the 2 m temperature for purely scattering aerosols due to radiative cooling.The purely scattering aerosols decrease the ABL temperature and enhance the capping inversion,further reducing the ABL height.     

多普勒雷达数据在海南省人工增雨效果评估中的应用

采用地面降水资料、多普勒雷达数据、探空资料等,利用自主开发的系统软件对实测资料进行增雨效果统计检验,通过目标区作业前后雷达参量的演变或目标区与对比区的回波参量的差异,来完整的分析2010年8月11日海南西部多点作业情况的催化效果。物理统计分析结果显示,催化一般在作业后半小时内起到效果并达到最强,目标区的最大强度、强回波区面积、液态水含量、回波顶高的增大率大于对比区的值,催化作业确实延长了目标云的寿命。     

一种利用反S数学模型自动确定地图目标分形无标度区的新方法

在观测尺度r的取值范围足够大时,地图目标的Richardson曲线往往呈现反S形态。根据这一特点,采用反S数学模型———带导数三次多项式模型拟合Richardson曲线,并根据该模型推导出分形无标度区间的计算公式,提出一种自动确定地图目标分形无标度区的新方法,最后通过实验验证本方法的可行性和有效性。     

Monin–Obukhov Similarity Functions for the Structure Parameters of Temperature and Humidity

Monin–Obukhov similarity functions for the structure parameters of temperature and humidity are needed to derive surface heat and water vapour fluxes from scintillometer measurements and it is often assumed that the two functions are identical in the atmospheric surface layer. Nevertheless, this assumption has not yet been verified experimentally. This study investigates the dissimilarity between the turbulent transport of sensible heat and water vapour, with a specific focus on the difference between the Monin–Obukhov similarity functions for the structure parameters. Using two datasets collected over homogeneous surfaces where the surface sources of sensible heat and water vapour are well correlated, we observe that under stable and very unstable conditions, the two functions are similar. This similarity however breaks down under weakly unstable conditions; in that regime, the absolute values of the correlations between temperature and humidity are also observed to be low, most likely due to large-scale eddies that transport unsteadiness, advection or entrainment effects from the outer layer. We analyze and demonstrate how this reduction in the correlation leads to dissimilarity between the turbulent transport of these two scalars and the corresponding Monin–Obukhov similarity functions for their structure parameters. A model to derive sensible and latent heat fluxes from structure parameters without measuring the friction velocity is tested and found to work very well under moderately to strongly unstable conditions (−z/L > 0.5). Finally, we discuss the modelling of the cross-structure parameter over wet surfaces, which is crucial for correcting water vapour effects on optical scintillometer measurements and also for obtaining surface sensible and latent heat fluxes from the two-wavelength scintillometry.     

基于太湖地区MFRSR遥感大气气溶胶光学特性和大气污染状况

利用2008年5月16日至2009年4月17日太湖地区多光谱旋转遮光辐射仪（multi—filter ro—tating shadow—band radiometer,简称MFRSR）的观测资料进行反演,得出415、500、615、675和870nm5个波段大气气溶胶光学厚度（aerosol optical depth,简称AOD）及各季节浑浊度系数和波长指数的统计结果。结果表明,5个波段AOD的最大值分别为1．9、1．6、1．3、1．2和1．0;它们谱分布的半宽度分别为0．90、0．70、0．55、0．45和0．25;AOD频率分布极大值处所对应的AOD值分别为0．750、0．550、0．475、0．425和0．425。5个波段AOD的平均值在春季最大,夏季次之,除870nm外,均为冬季最小。浑浊度系数变化范围为0～1．25,其中大于0．2的占97％以上,大于0．4的占66％以上。春季、夏季、秋季和冬季的波长指数变化范围分别为0～3．0、0～2．8、0．2～2．0和0．2～2．0,表明太湖地区大气污染较为严重,且受人为源的影响显著。相对于秋冬季,春夏季有较大粒径的气溶胶粒子存在。     

基于“钻石模型”的我国地理信息产业国际竞争力分析

利用波特"钻石模型"理论,从生产要素、需求条件、结构与竞争、相关支持产业、政府推动和机会等六个方面对我国地理信息产业竞争力进行了分析,找到了我国地理信息产业在国际发展道路上存在的优势和不足,并提出相应对策。     

浅谈包头市1∶5000地形图缩编技术

主要介绍利用大比例尺地形图数据进行缩编的技术方法,以及在编制过程中的综合取舍原则.     

土地利用/景观格局对水环境质量的影响

土地利用/景观格局已成为影响中国水环境质量的重要因素,但目前仍然欠缺土地利用/景观格局和水环境质量之间复杂关系的深入研究。以湟水流域小峡桥断面上游为例,兼顾水环境承载力与人为活动所产生的压力,建立土地利用/景观格局对水环境质量影响的结构方程模型,计算不同土地利用/景观格局指标对水环境质量的贡献率。研究表明:点源污染是湟水流域水环境质量恶化的主要因素,其贡献率最大(37.3%);而土地利用/景观格局的4个指标(不透水面面积占比、建设用地中绿地面积占比、湿地连通性和湿地聚集度)对水环境质量的贡献率相对较大,分别为9.14%、 7.91%、 7.44%和6.96%。加大点源污染控制力度、增强湿地连通性与聚集度、增大建设用地中绿地面积并减少不透水面面积是改善湟水流域小峡桥断面上游水环境质量的有效措施。     

复杂环境下深基坑优化设计探讨

目前城市空间日益紧缺,在城市内进行基坑开挖面临的狭小空间、复杂环境问题也逐渐成为基坑工程设计的重点难点;同时,在工程设计整体向地下要空间的思路下,基坑大多开挖深度较深。结合北京市昌平区某基坑工程设计案例,介绍了复杂环境下基坑优化设计,该基坑紧邻周边建筑物,周边建筑物基础埋深、基础形式、建筑年代、使用功能各异,根据环境条件,设计采用了"多标高+降台阶+不同参数"的桩锚支护体系,同时在施工过程中实施动态设计管理,支护结构工艺简单、节约造价、动态灵活,同时保证了基坑工程安全,对类似工程具有借鉴作用。