人工引发雷电试验及其特征的初步分析

1989年夏季，我们在甘肃永登黑林子地区进行了用拖带接地金属细丝的火箭引发雷电的试验，获得了3次成功。本文分析了这3次引发雷电的放电特征。结果表明，放电是在雷暴云下部正电荷的作用下上行负流光的激发和传播过程，雷电人工引发时的地面电场为6－8kV/m。由一简单物理模式粗略地定量估算出了放电参数：中和电荷量约为12－5．3C,电荷 中心离地高度1．3－2．5km，和甘肃地区雷暴云下部正电荷中心高度范围一致。     

Rainfall effect on wind waves and the turbulence beneath air-sea interface

Rainfall effects on wind waves and turbulence are investigated through the laboratory experiments in a large wind-wave tank. It is found that the wind waves are damped as a whole at low wind speeds, but are enhanced at high wind speeds. This dual effect of rain on the wind waves increases with the increase of rain rate, while the influence of rainfall-area length is not observable. At the low wind speed, the corresponding turbulence in terms of the turbulent kinetic energy （TKE） dissipation rate is significantly enhanced by rain- fall as the waves are damped severely. At the high wind speed, the augment of the TKE dissipation rate is suppressed while the wind waves are enhanced simultaneously. In the field, however, rainfall usually hin- ders the development of waves. In order to explain this contradiction of rainfall effect on waves, a possibility about energy transfer from turbulence to waves in case of the spectral peak of waves overlapping the inertial subrange of turbulence is assumed. It can be applied to interpret the damping phenomenon of gas trans- fer velocity in the laboratory experiments, and the variation of the TKE dissipation rates near sea surface compared with the law of wall.     

Dynamical features of near-inertial motions in global ocean based on the GDP dataset from 2000 to 2019

Based on the latest oceanic surface drifter dataset from the global drifter program during 2000–2019, this study investigated the global variation of relative frequency shift(RFS), near-inertial energy(NIE) and inverse excess bandwidth(IEB) of near-inertial motions, and analyzed their relations with oceanic mesoscale dynamics, relative vorticity and strain. Compared with previous works, we have some new findings in this study:(1) the RFS was high with negative values in some regions in which we found a significant blue shift of the RFS in the equatorward of 30°N(S) and from 50°N to 60°N in the Pacific, and a red shift in the western boundary currents and their extension regions, the North Atlantic and the Antarctic Circumpolar Current regions;(2) more peak values of the NIE were found in global regions like the South Indian Ocean, the Luzon Strait and some areas of the South Ocean;(3) the global distribution of the IEB were characterized by clear zonal bands and affected by vorticity and wind field;(4)the RFS was elevated as the absolute value of the gradient of vorticity increased, the IEB did not depend on the gradient of vorticity, and the eddy kinetic energy(EKE) weakened with the decrease of the absolute value of RFS;(5) the NIE decreased with increasing absolute value of the relative vorticity and the gradient of vorticity, but it increased with increasing strain and EKE when EKE was larger than 0.003 2 m~2/s~2.     

辽西地区中生代义县旋回火山活动特征分析

辽西地区广泛发育中生代火山岩,其中以义县旋回火山岩最为发育。本文在对辽西地区义县旋回火山岩微量元素地球化学特征研究的基础上,认为义县旋回火山岩具有同源性质,由壳幔混溶物质作用于统一的火山活动过程中产生。     

桂林岩溶区大气降水的化学特征分析

2009年1月至2010年12月期间,对处于岩溶区的桂林市降水进行了连续采样测试分析。研究结果表明:(1)桂林市区降水的pH平均值为4.83,降水的电导率平均值为65μS/cm,SO42-、NO3-和Ca2+、NH4+分别是最主要的阴阳离子。(2)桂林市降水各主要离子含量、降雨量和电导率表现出明显的季节差异,其中Ca2+、Mg2+含量在夏、冬季较高,春、秋季较低。(3)降雨量和TDS呈现出良好的负相关关系, SO42-和NO3-以及Ca2+和Mg2+之间则具有较好的正相关关系。(4)2009—2010年与1994—1995年相比,降水中的离子含量增加了1.16倍,降水的pH值有所增高,但仍在酸雨范围之内。在桂林酸雨形成中,降水的NO3-贡献明显增强。(5)通过2012年3月1—6日连续6天的降水监测,发现pH、降雨量和电导率三者呈现出良好的相关性。      

鄂尔多斯盆地马家沟组白云岩地球化学特征及白云岩化机制分析

由岩石学和地球化学研究表明:马家沟组白云岩主要为泥微晶白云岩和晶粒白云岩两种。泥微晶白云岩常与石膏或岩盐伴生,阴极发光呈中等橘红色光,有序度低,具较高的Sr、Na含量,与泥晶灰岩具相似的δ¹³C分布区间及稀土元素配分模式,Sr同位素值接近同期海水,包裹体均一温度近于地表温度,表明白云岩化流体为与海水密切相关的高盐度流体,为准同生白云岩化,可用蒸发泵模式解释其成因。晶粒白云岩伴生矿物少,偶见黄铁矿,晶体结构多曲面他形,阴极发光为中-弱橘红色光,有序度高,Sr含量较低,Na、Mn含量与泥微晶白云岩相近,稀土元素配分模式与泥微晶白云岩相似且与泥微晶灰岩相近,δ¹³C分布区间与泥微晶灰岩趋于一致,包裹体均一温度较高,说明晶粒白云岩与泥微晶白云岩具相似的白云岩化流体,该种白云岩为埋藏白云岩化,上覆沉积物不断压实封存卤水使其侧向流动为白云岩化提供了源源不断的Mg离子。     

鄂尔多斯盆地南部马莲河流域地下水中锶富集特征及成因分析

马莲河流域地处鄂尔多斯盆地南部黄土高原区,按储水介质和埋藏条件可将地下水分为黄土潜水、基岩潜水和基岩承压水三类,利用2015—2018年流域的295组地下水水化学数据,分析了地下水中锶(Sr²⁺)的质量浓度水平、垂向分布及沿流向分布的特征,并采用因子相关性研究地下水中Sr²⁺的来源和富集成因。结果表明:马莲河流域地下水富锶现象显著,黄土潜水、基岩潜水和基岩承压水中锶的平均质量浓度分别为1.14 mg/l、1.39 mg/l和5.24 mg/l;地下水中锶富集成因主要是含锶矿物天然状态下的水-岩作用,黄土潜水、基岩潜水和基岩承压水三类地下水中Sr²⁺的主要来源分别为碳酸盐岩与铝硅酸盐岩、碳酸盐岩与硫酸盐和碳酸盐矿物的溶滤作用;地下水中Sr²⁺的质量浓度沿流向呈逐渐增大的趋势,在不同区域中随深度变化的趋势不一致。     

Developing the science product algorithm testbed for Chinese next-generation geostationary meteorological satellites: Fengyun-4 series

Fengyun-4A (FY-4A), the first of the Chinese next-generation geostationary meteorological satellites, launched in 2016, offers several advances over the FY-2: more spectral bands, faster imaging, and infrared hyperspectral measurements. To support the major objective of developing the prototypes of FY-4 science algorithms, two science product algorithm testbeds for imagers and sounders have been developed by the scientists in the FY-4 Algorithm Working Group (AWG). Both testbeds, written in FORTRAN and C programming languages for Linux or UNIX systems, have been tested successfully by using Intel/g compilers. Some important FY-4 science products, including cloud mask, cloud properties, and temperature profiles, have been retrieved successfully through using a proxy imager, Himawari-8/Advanced Himawari Imager (AHI), and sounder data, obtained from the Atmospheric InfraRed Sounder, thus demonstrating their robustness. In addition, in early 2016, the FY-4 AWG was developed based on the imager testbed—a near real-time processing system for Himawari-8/AHI data for use by Chinese weather forecasters. Consequently, robust and flexible science product algorithm testbeds have provided essential and productive tools for popularizing FY-4 data and developing substantial improvements in FY-4 products.     

Semi‐analytical solution to one‐dimensional consolidation for unsaturated soils with semi‐permeable drainage boundary under time‐dependent loading

This paper presents semi‐analytical solutions to Fredlund and Hasan's one‐dimensional consolidation of unsaturated soils with semi‐permeable drainage boundary under time‐dependent loadings. Two variables are introduced to transform two coupled governing equations of pore‐water and pore‐air pressures into an equivalent set of partial differential equations, which are easily solved by the Laplace transform. The pore‐water pressure, pore‐air pressure and settlement are obtained in the Laplace domain. Crump's method is adopted to perform the inverse Laplace transform in order to obtain semi‐analytical solutions in time domain. It is shown that the present solutions are more general and have a good agreement with the existing solutions from literatures. Furthermore, the current solutions can also be degenerated into conventional solutions to one‐dimensional consolidation of unsaturated soils with homogeneous boundaries. Finally, several numerical examples are provided to illustrate consolidation behavior of unsaturated soils under four types of time‐dependent loadings, including instantaneous loading, ramp loading, exponential loading and sinusoidal loading. Parametric studies are illustrated by variations of pore‐air pressure, pore‐water pressure and settlement at different values of the ratio of air–water permeability coefficient, depth and loading parameters. Copyright © 2017 John Wiley & Sons, Ltd.