一次梅雨锋暴雨的数值模拟及位涡诊断

为了探讨暴雨与湿位涡场分布特征之间的关系,利用NCEP 1°×1°间隔6 h的再分析资料,通过计算湿位涡（MPV）的垂直分量(MPV1)和水平分量(MPV2),对华北一次暴雨过程的湿位涡场进行了诊断分析。结果表明：此次暴雨发生在对流层低层等θ_se线密集带内,降水前对流层低层MPV1 < 0、MPV2 > 0,暴雨区存在对流不稳定和斜压不稳定;暴雨区位于对流层低层MPV1、MPV2正负过渡带的等值线密集带内,有利于水汽辐合和垂直涡度的加强;主要降水期间,850 hPa层MPV1起主导作用,MPV1负值增大、MPV2正值减小,降水后期,MPV1 > 0、MPV2几乎为0,大气层结接近对流稳定。低层湿位涡中心的时空分布与暴雨的发生和落区有很好的对应关系。

     

海上中距离跨海高程传递方法比较

远离岸线的中距离(30~50 km)海域缺少测绘基础资料,高程传递尚未形成相应的作业体系。为满足海上工程建设的精度要求,采用同步验潮平均海面传递法、GNSS/水准传递法以及DTU18全球平均海面模型传递法,在山东省半封闭海域与开阔海域进行了中距离海上高程传递实验。实验结果表明,15天同步验潮平均海面传递法与GNSS/水准法的精度相当(厘米级),与DTU18全球平均海面模型传递法进行直接传递的差异在15 cm内,可为不同测绘基础条件下海上风电高程基准传递提供作业参考。     

基于CloudSat资料的中国及周边地区各类云的宏观特征分析

利用2006年7月—2009年4月的CloudSat2B-CLDCLASS云分类资料,针对中国及周边地区(0°—60°N,70°—140°E)各类云量和垂直结构参数的地理分布及季节变化进行了统计分析,并根据气候特征的地域差异从该区域选出8个子区域,逐区统计了各类云的垂直结构特征。结果表明,各类云量的分布存在较明显的区域差异和季节变化;青藏高原和帕米尔高原地区卷云、高层云和高积云等中高云的高度和厚度相对较小,陆上深对流云的云底高度大于海上,而热带、副热带地区云顶高度大于中纬度地区;除积云、层积云和雨层云外,中国南方地区其他各类云的云层厚度均大于北方地区;除了层积云外,其他各类云的云顶高度在各区域都存在比较明显的季节变化,低云云底高度的季节变化和区域差异都很小,而中高云的云底高度除了在印度洋季风区、南海和西太平洋地区季节差异较小外,其他地区季节差异较明显,各个地区在任何季节内,深对流云厚度最大,层积云最小;各类云出现频率随高度的分布具有较明显的区域差异;卷云与高积云的相关性比较强,经常相伴出现,夏季更加明显,而雨层云和深对流云之间相互排斥,两者几乎不可能同时出现。此外,统计中国及周边地区各类云的水平均一性发现,中...     

A study of the environmental influence on the amplitude of lee waves

A three-layer theoretical model is used to calculate the lee wave of a real example occurring over Blue Ridge in Pittsburgh, in which the maximum vertical velocity is 0.11 m s^-1. Based on this, the influence of changes in the thickness and values of the Scorer parameter in each layer are analyzed. It is shown that the influence of each layer parameters on the lee-wave amplitude is different, and the amplitude is more sensitive to the changes in the lower layer. Since the environment changes can affect the Scorer parameter profile, the influence of the environment on the amplitude is studied. The results show that the amplitude will decrease in the daytime because of solar heating, and increase at night because of radiational cooling, according to observational data. The case is also simulated by the Advanced Regional Prediction System （ARPS） model. The simulated amplitude is 0.089 m s^-1, which is close to the calculated result. Numerical sensitivity experiments are performed to test the former calculated experiments. The simulated results are consistent with the analytically calculated results.     

三层模型背风波的计算分析和数值模拟

本文将背风波三层模式的理论应用于典型的背风波个例,判断了其解所属的类型,计算了这些个例的波长;指出当有多个波解存在时,最长波长所对应的波解是实际解;本文还用ARPS模式对这些个例作了数值模拟,模拟结果与解析解则有较好的一致性。     

Theory and Application of Pseudo-Reservoir Hydraulic Stimulation for Coalbed Methane Indirect Extraction in Horizontal Well: Part 1—Theory

Pseudo-reservoir stimulation in horizontal well is an effective technique for indirectly extracting coalbed methane (CBM) in soft coal from the surrounding rocks (pseudo-reservoir). However, systematic studies of the theory and on-site application of this technique are still lacking, which severely hinders its application. In this paper, the technical principles of pseudo-reservoir stimulation are analyzed firstly, and then, the technical advantages are demonstrated by experimental tests and theoretical analysis. The results show that the pseudo-reservoir generally possesses considerable gas adsorption capacity, with the gas content of 1.56–4.22 cm³/g (avg. 2.51 cm³/g) in Well XC-01, which can be extracted as supplementary resources. The fracability of the pseudo-reservoirs is 0.73–0.92, which is much higher than that of the coal seam, i.e., 0.03–0.43. Meanwhile, the compressive and tensile strength and cohesion of the pseudo-reservoir are higher than those of the coal seam, indicating pseudo-reservoir stimulation is more conducive to forming fracture network, and maintaining wellbore stability and fracture conductivity. The technical feasibility of pseudo-reservoir stimulation is determined by the regional geological conditions, showing simple tectonic conditions and well-developed surrounding rocks with high fracability and mechanical strength but low permeability, water sensitivity and water content are beneficial for the technique application. Note that the fracture conductivity in pseudo-reservoir is more stable and higher than that in coal seam, pseudo-reservoir stimulation is beneficial for the CBM extraction from both hard and soft coal seams. By minimizing the gas diffusion distance, this technique overcomes the technical obstacles to the CBM commercialized production in soft coal.

     

侧扫声呐系统在荣成海流能电站示范工程中的应用

介绍了侧扫声呐系统在荣成海流能电站示范工程中的应用,对侧扫声呐系统的工作原理、图谱的特点及影响图谱影像质量的因素进行了分析,基于海流能示范工程扫测图谱影像进行了数据处理与特征提取,并将地貌分类成果应用到设计施工中取得了较好的效果;对工程应用中遇到的问题进行了总结。     

利用ATOVS反演产品分析“云娜”台风

ATOVS能接收到穿透台风中心密实云区的微波辐射信息, 利用ATOVS大气参数反演产品分析0414号台风“云娜”的热力结构特征。在准静力平衡假设的前提下, 根据ATOVS对“云娜”台风监测相匹配的4个时次数据, 分别计算出相应的中心海平面最低气压, 同中央气象台利用可见光和红外技术得到的台风报告值相比, 平均偏差为11.8 hPa, 它随时间的变化能显示台风强度演变的过程。     

车载探测系统在近地面污染监测中的应用

文章介绍了车载粒子探测系统所使用的设备、显示分析软件以及2000年6月和12月在北京市城市污染大气探测中获取的数据。探测结果表明：北京市夏季和冬季近地面悬浮粒子浓度存在较大差异；同一季节北京城区及周边地区近地面悬浮粒子浓度存在较大差异；同一地区同一季节白天与黑夜存在较大差异。车载探测系统的观测试验表明：该套车载探测系统能连续记录近地面粒子尺度、汽车行驶轨迹和速度，其测量频率高，机动灵活，不受天气条件的影响；增加光阵探头个数，可以对0．1～9300．0μm的雾、气溶胶、雨和雪等粒子进行测量；可较好地应用于地面污染监测，同时还可用于云雾人工影响天气作业的地面监测。