二叠纪—三叠纪古气候研究进展——泛大陆巨型季风气候:形成、发展与衰退

巨型季风是指二叠纪—三叠纪期间泛大陆上存在的强烈季节风,它的形成与泛大陆的形状、海陆分布及大陆的纬向分布密切相关。从晚石炭世泛大陆的聚合至晚侏罗世—早白垩世泛大陆裂解,巨型季风经历了形成、发展到衰退的过程。在三叠纪,泛大陆很大且几乎关于赤道对称,巨型季风达到最大强度。它对古气候、古环境、古生物及沉积等都产生了深刻的影响,使泛大陆低纬度地区呈现出干旱和潮湿交替的气候特征,蒸发岩和红层广泛分布;高纬度地区温暖潮湿,煤层大量分布;科罗拉多高原(美国西部)、西特提斯(欧洲)和东特提斯(中国)等地的二叠纪—三叠纪沉积地层也显示了受巨型季风影响的特征。     

Mineral-microbe interactions: a review

The studies of mineral-microbe interactions lie at the heart of the emerging field of Geomicrobiology, as minerals and rocks are the most fundamental earth materials with which microbes interact at all scales. Microbes have been found in a number of the Earth’s extreme environments and beyond. In spite of the diverse geological environments in which microbes are found and diverse approaches taken to study them, a common thread, mineral-microbe interactions, connects all these environments and experimental approaches under the same umbrella, i.e., Geomicrobiology. Minerals and rocks provide microbes with nutrients and living habitats, and microbes impact rock and mineral weathering and diagenesis rates through their effects on mineral solubility and speciation. Given a rapid growth of research in this area in the last two decades, it is not possible to provide a comprehensive review on the topic. This review paper focuses on three area, i.e., microbial dissolution of minerals, microbial formation of minerals, and certain techniques to study mineral-microbe interactions. Under the first area, three subjects are reviewed; they include siderophores as important agents in promoting mineral dissolution, microbial oxidation of reduced minerals (acid mine drainage and microbial leaching of ores), and microbial reduction of oxidized minerals. Under the second topic, both biologically controlled and induced mineralizations are reviewed with a special focus on microbially induced mineralization (microbial surface mediated mineral precipitation and microbial precipitation of carbonates). Under the topic of characterization, the focus is on transmission electron microscopy (TEM) and electron energy loss spectroscopy. It is the author’s hope that this review will promote more focused research on mineral-microbe interactions and encourage more collaboration between microbiologists and mineralogists.     

Analysis and characterization of the synergistic AIRS and MODIS cloud-cleared radiances

The Atmospheric Infrared Sounder (AIRS) and MODerate-Resolution Imaging Spectroradiometer (MODIS) on board NASA Earth Observing System (EOS) Aqua spacecraft measure the upwelling infrared radiance used for numerous remote-sensing- and climate-related applications. AIRS provides high spectral resolution infrared radiances, while MODIS provides collocated high spatial resolution radiances at 16 broad infrared bands. An optimal algorithm for cloud-clearing has been developed for AIRS cloudy soundings at the University of Wisconsin-Madison, where the spatially and spectrally collocated AIRS and MODIS data has been used to analyze the characteristic of this algorithm. An analysis and characterization of the global AIRS cloud-cleared radiances using the bias and the standard deviation between the cloud-cleared and the nearby clear measurements are studied. Scene inhomogeneity for both land- and water-surface types has been estimated to account for the assessed error. Both monthly and seasonal changes of global AIRS/MODIS cloud-clearing performance also have been analyzed.     

综合物探技术在煤系上覆薄硬岩矿区的应用初探——以山西潞安集团司马矿区为例

山西潞安集团司马矿区东高西低,西部延至长治盆地,矿区水系发育。主采3#煤层埋藏较浅,层位稳定。新生界不整合于下伏基岩之上,厚度变化较大,属典型的薄硬岩煤矿区。为准确提供矿区煤炭开采上限的地质依据,采用了综合勘探技术,其中利用三维地震勘探技术追踪新生界底面反射波及第四系"天窗"位置,利用直流电法与瞬变电磁法提供电性分层,并对其解释结果进行相互印证。勘探实例表明,三维地震勘探、电法勘探与钻探的综合运用不仅可解决薄硬岩煤矿区新生界厚度、含水层富水性及第四系缺失等问题,还可提供新生界含水层与基岩含水层之间的水力联系、制约因素等资料。     

Two-dimensional horizontal modeling of fine-sediment transport at the South Channel–North Passage of the partially mixed Changjiang River estuary,China

Tidal flow and fine-sediment transport at the South Channel–North Passage of the partially-mixed Changjiang River estuary were studied using a two-dimensional horizontal (2DH) numerical model. This 2DH model was achieved by depth-integrating the momentum and convection–diffusion equations. The Alternating Direction Implicit scheme was used to solve the governing equations. The iterative method was adopted for the calculation of convection and diffusion terms of momentum equation. Comparisons between calculated and measured results (tidal elevations and depth-averaged velocities) have shown reasonable agreement. Horizontal distributions of tidal current velocity and suspended sediment concentration were qualitatively consistent with observations. Those modeled results were analyzed to elucidate the mechanisms for the formation of the turbidity maximum and intratidal variations in fine-sediment transport processes.     

獐子岛海域和胶州湾表层微微型浮游植物丰度和生物量的季节变化比较

为全面了解黄海典型海区微微型浮游植物的季节变化特征,于2009年7月至2010年6月在北黄海獐子岛海域和2010年1~12月在南黄海胶州湾进行逐月调查采样,利用流式细胞仪检测了表层海水中微微型浮游植物(picophytoplankton)的丰度,包括聚球藻(Synechococcus,SYN)和微微型真核浮游植物(picoeukaryotes,PEUK),并分析了其与环境因子的关系。獐子岛海域和胶州湾SYN和PEUK全年广泛分布,獐子岛海域SYN丰度范围在0.05×10³~120.00×10³cells/mL之间,丰度在秋季最高;胶州湾SYN丰度范围在0.02×10³~61.80×10³cells/mL之间,丰度在夏季最高。獐子岛海域PEUK丰度范围在0.01×10³~18.76×10³cells/mL之间,丰度在秋季最高;胶州湾PEUK丰度范围在0.25×10³~95.57×10³ cells/mL之间,丰度在春季最高。獐子岛海域微微型浮游植物丰度组成以SYN为主;而胶州湾以PEUK为主。PEUK是两海区微微型浮游植物生物量的主要贡献者。相关性分析结果表明,温度是影响两海区SYN丰度季节变化的最主要因素;影响PEUK季节分布的因素不完全一致,獐子岛海域PEUK丰度主要受温度调控;胶州湾PEUK丰度主要受温度和营养盐浓度影响。与已有研究比较,这两个海区的微微型浮游植物生物量对浮游植物生物量的贡献明显高于其他温带沿岸海域,预示微微型浮游植物在獐子岛海域和胶州湾生态系统中的重要作用,值得进一步深入研究。     

空心块体水沙动力及泥沙淤积特性研究

空心块体具有良好的阻水和促淤功能,近年来被广泛用于生态修复工程。本文结合水槽试验及Flow-3D数值模拟,分析了开敞型和半封闭型空心块体的阻水效应和泥沙淤积特性。结果表明:空心块体的开孔率对内部水流流速、紊动强度起主导作用,开孔率较小的半开敞型空心块体减速、制紊效果更强;开敞型和半封闭型空心块体近底层悬沙浓度分别增大56%和75%,两者均有利于促进泥沙在块体内部淤积,近底层水流紊动越强,泥沙淤积形态差异越大;空心块体所营造的低流速、泥沙微淤、内外连通的水沙环境是大型底栖生物的生境需求,半封闭型空心块体内部的低紊动水流结构更有利于大型底栖生物的栖息、繁衍。     

科技创新、技术推广与海水养殖业全要素生产率

为促进我国海水养殖业的高质量可持续发展,文章根据科技创新、技术推广与海水养殖业全要素生产率之间的影响机理构建理论模型,选取2006-2018年我国从事海水养殖业的沿海地区相关数据和相关变量,实证检验科技创新对海水养殖业全要素生产率的影响以及技术推广在该影响机制中发挥的作用,并提出发展建议。研究结果表明：科技创新对提高海水养殖业全要素生产率和技术推广均具有显著的促进作用;技术推广对提高海水养殖业全要素生产率具有显著的促进作用,且在科技创新提高海水养殖业全要素生产率的影响机制中发挥中介效应;经替换变量法和补充变量法检验,实证检验结果具有稳健性;未来我国发展海水养殖业应进一步增强科技创新和技术推广能力。     

台风“烟花”的主要特点和路径预报难点分析

对2021年第6号台风“烟花”的主要特点与路径预报重大调整过程中出现的难点问题进行分析和研究,得出主要结论如下。(1)“烟花”移动缓慢,是首个两次登陆浙江的台风,在浙北和杭州湾附近地区长时间滞留。(2)降雨影响范围广、累计降雨量大、大风持续时间长。(3)反映出来的重要难点问题有:当多数模式预报出现一致的偏差时,预报员难以做出订正,有必要开展对模式中台风重要影响系统(高空冷涡、热带对流层上层槽等)的预报检验工作;台风移速缓慢的定量程度难以把握,需要通过总结历史个例和敏感性试验等方法开展东侧台风对西侧台风移动缓慢影响的定量研究;西风带槽/脊对副热带高压退/进快慢的定量影响把握困难,影响北上台风转向点的预报,特别是当不同模式有分歧的时候预报难度更大。     

深海作战战场环境保障需求问题研究

深海战场空间的独特性和超前性引发了深海军事的发展和变革,并逐步改变军事斗争的战略态势。因此,迫切需要加速形成深海战场环境保障能力,为维护我国安全和海外利益拓展等提供基础支撑。总结归纳了深海概念及环境影响,提出面临形势与未来挑战,深入分析深海战略威慑、水下航行、导航定位、 预置武器和预报预警等场景下的战场环境保障需求,最后提出深海战场环境保障建设的措施建议。