为研究徐州冬季雾-霾天气形成过程中颗粒物粒径及气溶胶光学特性的变化特征,分析了2014年12月1日-2015年2月28日徐州大气颗粒物质量浓度（PM（10）、PM（2.5）、PM1）、数浓度（0-1μm、1-2.5μm、2.5-10μm）和气溶胶光学特性等数据.结果表明：0-1μm粒径范围细颗粒物的大量增多是引发徐州冬季雾-霾天气的主要因素,徐州冬季地面风速小（静风或轻风天气）,较高的大气相对湿度对雾-霾的形成和维持起着重要影响作用.持续时间较长的雾霾天气,因颗粒物吸湿增长和水汽附着,1-10μm粒径范围大气颗粒物在雾霾时段易发生沉降而减少,后随相对湿度降低雾霾转为短时间的霾天气,1-10μm颗粒物数浓度大幅上升.徐州冬季500nm波段AOD total和AOD fine mode具有相同的变化趋势,雾-霾日AOD total和AOD fine mode显著高于非霾日.AOD fine mode与AOD coarse mode的比值雾-霾日亦明显高于非霾日,而且在雾-霾日Angstrom波长指数主要集中在1-1.6,表明徐州冬季雾-霾时段大气中细颗粒物为主控粒子.
Underground coal mining inevitably results in land surface *** information on land surface subsidence is important in the detection of surface ***,conventional data acquisition techniques cannot always retrieve inform...
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Underground coal mining inevitably results in land surface *** information on land surface subsidence is important in the detection of surface ***,conventional data acquisition techniques cannot always retrieve information on whole subsidence *** study focuses on the reconstruction of a digital elevation model（DEM） with terrestrial laser scanning（TLS） point cloud ***,the methodology of the DEM with terrestrial 3-dimensional laser scanning is ***,a DEM modeling approach that involves the application of curved non-uniform rational B-splines（NURBS） surface is put ***,the performance of the DEM modeling approach with different surface inverse methods is *** results indicate that the DEM based on the point cloud data and curved NURBS surface can achieve satisfactory *** addition,the performance of the hyperbolic paraboloid appears to be better than that of the elliptic *** reconstructed DEM is continuous and can easily be integrated into other *** features are of great importance in monitoring dynamic ground surface subsidence.
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