软土地基上静压预制桩承载力的工后增大效应

分析了软土地基上预制桩承载力的时效性机理，介绍了几种研究承载力时效性的经验回归公式，结合工程说明应充分认识承载力时效性的科学性和利用这种规律潜在的巨大经济效益。     

一次冰雹过程人工催化的数值模拟试验

利用二维雹云模拟济南地区１９９６年７月２４日出现的一次冰雹过程，模拟结果表明对雹云２６个主要微物理过程双参数化较细致地描述对流过程的热，动力反馈和微物理特点２。根据计算结果，对该次冰雹过程进行了ＡｇＩ催化试验，结果得出在云发展初期对暖底雹云实施高浓度的冰晶催化，可起到减少地面冰雹和增加地面降水的作用。     

Focal mechanism dependence of static stress triggering of earthquakes

We perform a global statistical investigation into the problem of Coulomb stress triggering of earthquakes by using the Harvard CMT catalogue of shallow earthquakes from 1976 to 2001. We consider ‘earthquake pairs’, i.e., pairs of successive earthquakes occurring near each other with similar focal mechanisms, and address the problem of whether or not the change of the Coulomb failure stress (CFS) produced by the first earthquake of the pair ‘encourages’ the occurrence of the second one. An interesting feature is that such a Coulomb stress-triggering phenomenon has an apparent focal mechanism dependence: for thrust earthquakes, a more evident triggering effect can be observed.     

Mesoscale numerical simulation study of warm fog dissipation by salt particles seeding

Based on the dynamic framework of WRF and Morrison 2-moment explicit cloud scheme, a salt-seeding scheme was developed and used to simulate the dissipation of a warm fog event during 6–7 November 2009 in the Beijing and Tianjin area. The seeding effect and its physical mechanism were studied. The results indicate that when seeding fog with salt particles sized 80 μm and at a quantity of 6 gm~(-2) at the fog top, the seeding effect near the ground surface layer is negative in the beginning period, and then a positive seeding effect begins to appear at 18 min, with the best effect appearing at 21 min after seeding operation. The positive effect can last about 35 min. The microphysical mechanism of the warm fog dissipation is because of the evaporation due to the water vapor condensation on the salt particles and coalescence with salt particles.The process of fog water coalescence with salt particles contributed mostly to this warm fog dissipation. Furthermore, two series of sensitivity experiments were performed to study the seeding effect under different seeding amounts and salt particles sizes. The results show that seeding fog with salt particles sized of 80 μm can have the best seeding effect, and the seeding effect is negative when the salt particle size is less than 10 μm. For salt particles sized 80 μm, the best seeding effect, with corresponding visibility of 380 m, can be achieved when the seeding amount is 30 g m~(-2).     

Retrieval of effective leaf area index (LAIe) and leaf area density (LAD) profile at individual tree level using high density multi-return airborne LiDAR

As an important canopy structure indicator, leaf area index (LAI) proved to be of considerable implications for forest ecosystem and ecological studies, and efficient techniques for accurate LAI acquisitions have long been highlighted. Airborne light detection and ranging (LiDAR), often termed as airborne laser scanning (ALS), once was extensively investigated for this task but showed limited performance due to its low sampling density. Now, ALS systems exhibit more competing capacities such as high density and multi-return sampling, and hence, people began to ask the questions like—“can ALS now work better on the task of LAI prediction?” As a re-examination, this study investigated the feasibility of LAI retrievals at the individual tree level based on high density and multi-return ALS, by directly considering the vertical distributions of laser points lying within each tree crown instead of by proposing feature variables such as quantiles involving laser point distribution modes at the plot level. The examination was operated in the case of four tree species (i.e. Picea abies, Pinus sylvestris, Populus tremula and Quercus robur) in a mixed forest, with their LAI-related reference data collected by using static terrestrial laser scanning (TLS). In light of the differences between ALS- and TLS-based LAI characterizations, the methods of voxelization of 3D scattered laser points, effective LAI (LAIe) that does not distinguish branches from canopies and unified cumulative LAI (ucLAI) that is often used to characterize the vertical profiles of crown leaf area densities (LADs) was used; then, the relationships between the ALS- and TLS-derived LAIes were determined, and so did ucLAIs. Tests indicated that the tree-level LAIes for the four tree species can be estimated based on the used airborne LiDAR (R² = 0.07, 0.26, 0.43 and 0.21, respectively) and their ucLAIs can also be derived. Overall, this study has validated the usage of the contemporary high density multi-return airborne LiDARs for LAIe and LAD profile retrievals at the individual tree level, and the contribution are of high potential for advancing forest ecosystem modeling and ecological understanding.     

高陡岩石边坡软体护坡技术设计及施工实践

为了消除济南市燕翅山北侧采矿遗留的高陡岩石边坡的地质灾害隐患,恢复自然植被,通过施工砼基座、施工砼格构梁、砌筑软体生态袋和挂网喷播等多种技术方法进行了综合治理,消除了滑坡和崩塌等地质灾害隐患,整个坡面植被覆盖率超过99%,消除了视觉污染,恢复了当地生态环境,该工程成功的设计及施工实践对类似高陡岩石边坡有很好的指导和借鉴作用。     

The Extra-Area Effect in 71 Cloud Seeding Operations during Winters of 2008–14 over Jiangxi Province,East China

Effects of weather modification operations on precipitation in target areas have been widely reported, but little is specifically known about the downwind (extra-area) effects in China. We estimated the extra-area effect of an operational winter (November-February) aircraft cloud-seeding project in northern Jiangxi Province in eastern China by using a revised historical target/control regression analysis method based on the precipitation data in winter. The results showed that the overall seasonal average rainfall at the downwind stations increased by 21.67%(p=0.0013). This enhancement effect was detected as far as 120 km away from the target area. Physical testing was used to compare the cloud characteristics before and after seeding on 29 November 2014. A posteriori analysis with respect to the characteristics of cloud units derived from operational weather radar data in Jiangxi was performed by tracking cloud units. Radar features in the target unit were enhanced relative to the control unit for more than two hours after the operational cloud seeding, which is indicative of the extra-area seeding effect. The findings could be used to help relieve water shortages in China.     

吸湿性播撒对暖性对流云减雨影响的数值模拟

利用以色列特拉维夫大学二维面对称分档云模式（two-dimensional slab-symmetric detailed spectral bin microphysical model of Tel Aviv University）,对2016年9月4日16:00（北京时）前后我国华东地区的一次暖性浅对流云降水过程进行模拟,模式模拟的强回波中心高度和最大回波强度范围与观测基本一致。并在此基础上进行了小于1 μm的吸湿性核的播撒减雨试验,分别考虑了不同播撒时间、不同播撒高度以及不同播撒剂量的敏感性测试。结果表明:在云的发展阶段早期播撒能起到更好的减雨效果,播撒时间越早对大粒子生长过程的抑制作用越强,随着播撒时间向后推移,受抑制作用最显著的粒径段向小粒径端偏移;在云中心过饱和度大的区域下方进行播撒,减雨效果更加明显,当播撒剂量为350 cm-3时,地面累积降水量减少率可达23.3%;另外,随着播撒剂量的增加,减雨效果更加显著,甚至能达到消雨的效果。因此,在暖性浅对流云中合理地播撒小于1 μm的吸湿性核能达到较好的减雨或消雨效果。     

冰核观测中两种滤膜采样方法的比较

大气冰核观测是研究自然冷云降水和人工影响天气的一项基础性工作,滤膜—扩散云室法是观测冰核浓度的主要方法之一。为检测分析两种滤膜采集方法对冰核观测结果的影响,2011—2015年用自制的大气颗粒物采样器和FA-3型撞击式9级采样器开展了平行采样试验,采集的滤膜样本均在同一静力扩散云室中进行冰核活化显现分析。结果表明：自制采样器较9级采样器观测的冰核浓度高数倍甚至数十倍,但两者随季节和不同气象条件的变化表现出一致的起伏特征。自制采样器适用于对大气中总的冰核浓度分布及理化特征研究;9级采样器适用于对PM₁₀中不同粒径段大气冰核浓度和尺度分布以及理化特征的研究。滤膜法对冰核数量的低估与采样体积成正比,改变采样器气泵的抽气流量和控制采样体积对改进“体积效应”影响均有明显效果。