采用20世纪再分析版本2c数据集的云水量逐月再分析数据,通过数理统计方法,分析了1960~2014年全球、海洋和陆地上空云水量的分布和变化特征及其与水汽通量的关系.结果表明:1)全球云水量空间分布不均,海洋高于陆地且比例约为4﹕3,中低纬海洋、陆地上空云水量变化趋势分别为0.07 g m?2(10 a)?1和?0.04... 相似文献
将深度学习到时拾取、震相关联技术与传统定位方法联系起来,构建一套连续波形自动化处理与地震目录自动构建流程,对于高效充分利用地震资料,提升微震检测能力具有十分重要的意义.我们应用最新发展的迁移学习震相识别技术、震相自动关联技术,对长宁MS6.0地震震中附近21个台站震前半个月(6月1日—6月17日)的连续记录波形进行P、S震相识别、震相自动关联和初步定位,并应用传统绝对定位和相对定位技术得到了长宁地震震前微震活动的绝对和相对定位目录.其中绝对定位目录能在较小的误差范围匹配85%的人工处理目录,其发震时刻平均误差为0.36±0.07 s,震级平均误差为0.15±0.024级,水平定位平均误差为1.45±0.028 km,其识别的1.0级以下微震数目是人工的8倍以上,将长宁地震震前微震目录的检测下限提升至ML-1左右,证明了基于深度学习到时识取和REAL(Rapid Earthquake Association and Location,快速震相关联和定位技术)震相自动关联来构建微震目录具有较好的实用性.我们的自动地震目录揭示了长宁MS6.0主震所发生的区域震前异常频繁的微震活动,以及与区域内盐矿注水井的关联性,更好地描绘了这些微震活动的时空演化特征,其空间活动性分布特征与长宁MS6.0余震序列的分布一致.
A microscale air pollutant dispersion model system is developed for emergency response purposes. The model includes a diagnostic wind field model to simulate the wind field and a random-walk air pollutant dispersion model to simulate the pollutant concentration through consideration of the influence of urban buildings. Numerical experiments are designed to evaluate the model's performance, using CEDVAL(Compilation of Experimental Data for Validation of Microscale Dispersion Models) wind tunnel experiment data, including wind fields and air pollutant dispersion around a single building. The results show that the wind model can reproduce the vortexes triggered by urban buildings and the dispersion model simulates the pollutant concentration around buildings well. Typically, the simulation errors come from the determination of the key zones around a building or building cluster. This model has the potential for multiple applications; for example, the prediction of air pollutant dispersion and the evaluation of environmental impacts in emergency situations; urban planning scenarios;and the assessment of microscale air quality in urban areas. 相似文献
In Daye Iron Mine, the open-pit mining has ended and the underground mining started in 2003. The present pit slopes are as high as 430 m and the slope angle is up to 43°. During the process of open-pit to underground mining, the high-steep pit slopes would be affected by both open-pit mining and underground mining, and its deformation characteristics would become more complex. So in this paper, the trinity method of numerical simulation, model experiment and field test was adopted to analyze the displacement and stress fields systematically. The results show that: (1) Prominent rebound deformation occurs near the slope foot, which is induced by the unloading in open-pit mining. When it is backfilled to 0 m level, the rebound deformation decreases, which indicate that backfilling mass can restrict the deformation and improve the slope stability; (2) Subsidence dominates the slope deformation in open-pit to underground mining and it increases with an increasing elevation of monitoring point; the maximum horizontal displacement occurs in the lower part of the slopes, because the backfilled part is squeezed by both the north slope and the south slope, and it has a lower elastic modulus than the previous orebody; (3) The stress and its variability near the slope foot are much larger than other places, indicating that the slope foot is most affected by stress redistribution and stress concentration may occur here; the stress at other stress monitoring points changes little, indicating that the influence of open-pit to underground mining is local; (4) The effect of underground mining on the deformation of the faults is not prominent; (5) Mining operations in near-ground part affect more on the variation of deformation and stress of pit slopes than that in deeper part. 相似文献