地球磁层顶的漂移动力学Alfvn波不稳定性及其反常输运效应

本文用回旋动力学研究了磁层顶等离子体低频漂移动力学不稳定性.在β≥1附近发现两支不稳定的漂移动力学Alfvèn模(DKA).它们可在▽T(∥-▽n)(?)0时激发,速度剪切提供主要的自由能源.两支DKA均具有非零的(δE_y,δE_∥)和(δB_x,δB_∥).在湍动的非线性饱和状态下,δB_x的起伏可导致很强的反常输运,当|δB_x|=1nT时,D_⊥可达到10~9m~2/s的数量级.因此,DKA可能在太阳风-磁层耦合过程中起重要作用.     

江苏一次大范围的爆发性强浓雾过程研究

利用江苏省70个自动观测站和365个交通气象观测站资料,对2016年2月11日夜间至12日上午出现在江苏的一次大范围强浓雾天气过程进行分析。结果表明:这次强浓雾过程具有爆发性形成和加强的特征,大部分站点从1000m以上快速下降形成强浓雾,且部分站点存在多次爆发增强现象;夜间天空打开,长波辐射降温作用加强,是大范围强浓雾形成和爆发性发展的一个重要原因;同时,雾前降雨为本次强浓雾的形成创造了基础条件,也是日出后部分站点由于水汽蒸发增强而导致雾爆发性增强的直接原因;另外,雾前和雾期间近地层强逆温的存在为雾的爆发性发展提供了稳定的大气层结条件,而逆温顶附近低空急流的形成,也一定程度上促进了逆温的维持和加强,利于雾的爆发性发展。     

上海第四纪土层邓肯—张模型的参数研究

本文根据大量土样的三轴排水试验得到上海各主要土层的邓肯—张模型参数,讨论了模型参数的取值特点和变化规律。试验结果表明,粘土的k值明显小于砂土,但粘土的kur/k要大于砂土,粘土的kur/k在4~10之间,砂土的kur/k在2~7之间;k与φ具有明显的相关关系,k随φ近似按指数曲线变化;破坏比Rf的取值多在0.70~0.85之间;nur/n与n没有明显的关系,n值大多在0.5~1.0之间。     

西北地区农林牧业生产及农业结构调整对全球气候变暖响应的研究进展

受西北地区现代气候变化呈现冬暖夏干的影响, 甘肃黄土高原200 cm深土壤贮水量呈减少趋势, 适宜农作物生长时段减少2-3月. 黄土高原作物气候生产力呈下降趋势, 年递减率为10.45 kg·hm-2, 暖干型和冷干型气候对作物生长非常不利, 减产为4.3%～27.1%. 对畜牧业的影响利弊共存, 使牧区草场产草量和质量以及生产力下降;但牲畜死损率明显降低, 幼畜成活率明显增加;牲畜抓膘育肥利弊因素相当, 牲畜肉量呈波动式变化. 小陇山森林资源呈减少趋势, 90年代最为严重. 在全球变暖的气候变化下, 需要农林牧业结构发生重大调整, 提出了甘肃省以及祁连北坡、陇东、陇东南和陇南等4个具有代表性的重点地域的农林牧业种植结构调整发展战略与优化方案. 其研究结果为西北地区农林牧业安全生产、趋利避害、减轻不利影响提供科学的指导意见.     

Removal of Arsenic(V) from Aqueous Solutions by Lanthanum-loaded Zeolite

A new adsorption process for the removal of As（V） ion from aqueous solutions is studied in this paper using lanthanum-loaded zeolite. The removal efficiency of different adsorbents, activated alumina and activated carbon are obtained in the study for comparison. The results show that lanthanum-loaded zeolite is an effective adsorbent for the removal of As（V） from aqueous solutions. Then, the pH effect and regeneration of modified zeolite on the As（V） removing efficiency are also assessed. It functions with a wide range of pH （2-8）. After adsorption, zeolite adsorbed with As（V） ions can be regenerated successfully with 1 M NaOH. Based on the data obtained, an adsorption mechanism and the possible complex structure are tentatively presented. Compare to other adsorbents, easy availability of this adsorbent, excellent adsorption capacity, wide optimum pH range, and regeneration are expected to be utilized in practical operations.     

Thermodynamics and Microphysical Characteristics of an Extreme Rainfall Event Under the Influence of a Low-level Jet over the South China Coast

In this paper, the data of Automatic Weather Stations (AWSs), ERA5 reanalysis, sounding, wind profile radar, and dual-polarization radar are used to study an extreme rainfall event in the south China Coast on 11 to 12 May 2022 from the aspects of thermodynamics and microphysical characteristics under the influence of low-level jets (LLJs). Results show that: (1) The extreme rainfall event can be divided into two stages: the first stage (S1) from 0000 to 0600 LST on May 12 and the second stage (S2) from 0700 to 1700 LST on the same day. During S1, the rainfall is mainly caused by the upper-level shortwave trough and the boundary layer jet (BLJ), characterized by strong upward motion on the windward side of mountains. In S2, the combined influence of the BLJ and synoptic-system-related low-level jet (SLLJ) increases the vertical wind shear and vertical vorticity, strengthening the rainstorm. In combination with the effect of topography, a warm and humid southwest flow continuously transports water vapor to farther north, resulting in a significant increase in rainfall over the study area (on the terrain’s windward slope). From S1 to S2, the altitude of a divergence center in the upper air decreases obviously. (2) The rainfalls in the two stages are both associated with the mesoscale convergence line (MCL) on the surface, and the wind field from the mesoscale outflow boundary (MOB) in S1 is in the same direction as the environmental winds. Due to a small area of convergence that is left behind the MOB, convection moves eastward quickly and causes a short duration of heavy rainfall. In S2, the convergence along the MOB is enhanced, which strengthens the rainfall and leads to strong outflows, further enhancing the surface convergence near the MOB and forming a positive feedback mechanism. It results in a slow motion of convection and a long duration of heavy rainfall. (3) In terms of microphysics, the center of a strong echo in S1 is higher than in S2. The warm-rain process of the oceanic type characterizes both stages, but the convective intensity in S2 is significantly stronger than that in S1, featuring bigger drop sizes and lower concentrations. It is mainly due to the strengthening of LLJs, which makes small cloud droplets lift to melting levels, enhancing the ice phase process (riming process), producing large amounts of graupel particles and enhancing the melting and collision processes as they fall, resulting in the increase of liquid water content (LWC) and the formation of large raindrops near the surface.     

川西坳陷深盆气研究进展与问题讨论

川西坳陷总体上看具有与加拿大阿尔伯达盆地类似的地质条件，极可能发育深盆气藏。详细研究表明，两盆地在构造回返程度、地层压力特征、气源岩生气时代等方面存在较大差异，不宜将川西坳陷的天然气聚集简单地归结为阿尔伯达型深盆气藏。研究其成因和分布规律，应从该盆地的实际资料入手，进行成藏机理研究，而不能简单地借用已有的模式进行对比。研究认为，川西坳陷的天然气藏具有“气水倒置”的特征；川西坳陷的断裂体系深刻地影响着深盆气聚集成藏，导致盆地天然气的独特分布形式。对深盆气成藏诸控制因素，包括源岩厚度、有机质成熟度、生气强度、储集层厚度与物性、断裂构造特征等的综合研究，对川西坳陷深盆气藏的分布进行了预测。     

“路易贝贝”产出层位时代及其古环境

"路易贝贝"恐龙胚胎化石产于中国河南省南阳市西峡县阳城乡,位于西峡盆地上白垩统高沟组下(底)部,是Macroelongatoolithus xixaensis(西峡巨型长形蛋)的胚胎骨骼化石。西峡盆地上白垩统自下而上划分为高沟组、马家村组、寺沟组。高沟组产有丰富的恐龙蛋化石和少量恐龙骨骼化石,以及少量的双壳类、腹足类、介形类、轮藻、植物孢粉、植物化石碎片和丰富的遗迹化石。依据上述化石的地质时代并结合高沟组与上覆马家村组整合接触关系和寺沟组化石组合情况,以及高沟组与下伏泥盆系南湾组角度不整合接触关系和周边相邻盆地的地层对比,将西峡盆地高沟组地质时代置于晚白垩世中晚期的康尼亚克期(Coniacian)。高沟组下、中部为半干旱温热气候条件下的红色陆相类磨拉石建造的陆源碎屑岩,属间歇性的、以牵引流为主的浑水河流冲积扇沉积物;高沟组上部为冲积扇和辫状河沉积。"路易贝贝"所在层位的古地理环境是冲积扇扇端朝向南的、缓坡状宽阔平坦的冲积扇扇面,可归入冲积扇相-扇端亚相-漫流微相。     

一种结合特征拟合的水域信息提取方法

针对干旱半干旱区水域的重要性,开展基于环境减灾卫星的水环境遥感识别监测已成为目前水资源领域中的重要任务。该文利用LBV变换能显著突出地物信息的这一特征,以环境卫星为数据源探讨LBV变换方法。在分析L、V、B3类分量的基础上,以V-B及L-B为特征空间,结合波段阈值、二维散点分布与回归拟合方法,识别研究区的水域分布信息。结果表明,使用单一B分量阈值法能较完整地提取出水域信息。利用水体集群聚集程度高的方式提取的水体信息,在V-B及L-B特征拟合下也能完整地提取研究区内的水域信息。比较3种水体信息提取方法,无论是在误提取率还是在水体提取精度上,L-B特征拟合方法提取的效果最好,其次是V-B特征关系,B分量阈值法提取精度最低。     

试论国土资源管理在规避矿业权融资风险中的作用

山东是矿业大省,今后矿业权融资项目会越来越多,为规避可能产生的融资风险,国土资源管理部门应建立公开、公正、透明的矿业权市场,循序渐进开展矿业权融资备案业务,为投融资方提供必要的信息,忠实履行自身职责。