Modelling of Ocean Shallow Convection under Fast Ice in the Arctic

Ocean convection in the Antarctic has been studied many times and has been revealed to be responsible for ice-cover reduction. In the Arctic, proof of that phenomenon has not been documented. It is believed that this phenomenon happens on a smaller scale in the Arctic when local circulation of deep warmer water melts and slows ice production. An example of this is the North Water (NOW) polynya in northern Baffin Bay. A polynya is an area of open water in an otherwise ice-covered area. As ice forms under the fast ice near the boundary of the polynya, ocean salts (brine) are ejected from the newly formed ice. This water, which has an increased concentration of salt, sinks and is replaced by warmer water from below, and this slows ice formation. In our study a coupled one-dimensional thermodynamic snow–fast ice model incorporating ocean heat flux input via a shallow convection model was used. Ice thickness was calculated using a thermodynamic model that included a current-induced entrainment model and a convection model to account for brine rejection during ice growth. Atmospheric observations from Grise Fiord and Thule and ocean profiles around the NOW polynya near these sites were used as input to the model. This purely thermodynamic study enables us to obtain ice thickness values that can be compared with qualitative observations. This modelling study compares two sites related to the NOW polynya. The results indicate that the shallow convection model simulates the reduction of fast ice near Thule but not near Grise Fiord.     

用雷达观测资料改进MM5初始场的初步试验研究

采用同时调整热力学和动力学变量，并考虑湿度与温度的变化相协调的初始化方法，引进雷达资料改善MM5模式的初始场。试验结果表明：经过优化处理的初始场，显著提高了模式对降水特别是甚短时(0～6h)降水的落区和量的预报准确率。其中调整热力学变量对改进降水落区预报比动力学变量的调整更为重要。     

Cu3 N弹性和热力学性质的第一性原理研究

利用基于密度泛函理论的第一性原理全势线性缀加平面波方法,研究了立方反ReO₃结构Cu₃N在零温(0 K)零压下的平衡晶格常数、体弹模量及其对压强的一阶导数,计算结果与其他实验及理论结果基本相符. 同时得出Cu₃N的弹性常数,Poisson比等,并分析出Cu₃N在零温零压下是稳定的. 通过准谐Debye模型计算Cu₃N的热力学性质,得到了Cu₃N的晶格常数、等压比热容、等容比热     

地质流体状态方程

几乎所有的地球化学过程都有地质流体参加, 定量地了解地质流体的物理化学性质是定量研究地球化学过程的基础.100多年以来, 广大化学和实验地球化学工作者做了大量的实验测定工作, 可是所有这些工作之和, 仅仅覆盖地球范围内一个不大的温压空间, 远远不能满足地球化学研究的需要.近年来, 我们试图通过分子水平上的研究, 结合热力学和统计力学方面的知识, 在重现前人实验结果的基础上, 研究实验工作者没有或不能研究的温压和成分空间, 得到了一系列能够精确预测地质流体在广阔的温压范围内的物理化学性质的状态方程.这些状态方程不仅能够重现实验数据, 而且具有良好的外延能力, 可以应用于地球化学领域诸多方面的研究.重点讨论了几个状态方程(包括纯流体状态方程含水溶液状态方程和含盐-水-气的状态方程) 在预测流体的溶解度、相平衡、化学位和PVT性质方面的应用.简要介绍了近年来笔者应用分子动力学和蒙特卡罗模拟在地质流体研究方面所取得的成果      

全球温度变化的热力学平衡和最新发现

本文提出了一种新的研究全球气候温度变化的思路。为发现全球气候变化的宏观规律,把生物圈系统作为一个整体的物质进行研究,从而把纷繁复杂的全球气候温度变化问题归纳成经典物理学的热量与温度变化问题。给出了广义生物圈的热平衡测量Q值和温度变化的热力学公式,并在实际数据的基础上通过计算发现人类使用矿物燃料和核能所排放的热量理论上可使全球海平面每年升高35 mm或者可使大气对流层温度每年升高011 ℃。该发现表明:能源热量因素已成为影响全球温度变化的重要因素。     

CaSO4-C-H2O体系研究：模拟实验与热力学探讨

传统认为TSR成因的固态沥青(焦沥青)属于热化学反应的终端产物,不会对TSR的反应进程起到重要作用.本文以活性炭作为固态沥青(焦沥青)的模型化合物,开展了CaSO4-C-H2O体系的热模拟实验研究,探讨了CaSO4-C-H2O体系发生TSR的热力学特征.实验结果表明,CaSO4-C-H2O体系在300℃时即可启动TSR,主要生成CaCO3、H2S和CO2等产物.这一TSR门限温度要远低于以往室内利用气态或液态烃类进行的TSR模拟实验温度范围,与热力学计算结果一致.利用HSC Chemistry 5.0软件进行TSR过程模拟,发现25～200℃时CaSO4-C-H2O体系发生的TSR完全受动力学控制,在温度保持不变情况下,压力增大不利于CaSO4-C-H2O体系发生TSR.较少的含水量对TSR有一定促进作用,而含水量过多则可能抑制TSR的进行,含水量对TSR的影响可能与CaSO4在水中的饱和浓度有关.在一定的温度下,当体系pH≤2时,随着pH逐渐降低,CaSO4的量呈线性递减,但在沉积盆地地层水pH范围内(pH＞4),pH对TSR的作用可以忽略不计.CaSO4-C-H2O体系发生的TSR反应是一个放热过程,并且随着温度升高,反应热逐渐增大.在25～200℃范围内,TSR反应热为12.9～133 J/molCaSO4.热力学计算以及模拟实验结果均暗示,固态沥青(焦沥青)可能比烃类更容易参与TSR.     

Computer thermodynamic modeling of the transport and deposition of Sb and Au during the formation of Au-Sb deposits

Using the Chiller computer program, we performed modeling of the mechanisms of the joint transport and deposition of Au and Sb from various ore-forming solutions during the formation of Au-Sb deposits. Three models are considered by the example of the Uderei Au-Sb deposit in the Yenisei Ridge: (1) simple cooling (cooling only), (2) iso-enthalpy boiling (P = f(T)), and (3) solution–rock interaction (rock titration model). The behavior of Sb(III) and Au(I) in the system Au–Sb–Fe–Cu–Pb–Zn–As–H₂O–Cl–H₂S–CO₂ under hydrothermal conditions was studied. It is shown that both weakly alkaline (near-neutral) and reduced acidic Fe_aq²⁺-enriched low-chloride high-CO₂ and high-chloride hydrothermal solutions play a crucial role in the formation of gold parageneses of Au-Sb ores.     

海洋底栖古群落演替模式--以华蓥山茅口组腕足动物群落为例

以热力学理论和信息熵原理为基础,分析了古群落的热力学本质和信息熵的内涵,指出古群落演替可分为4个阶段:开始阶段、发展阶段、顶极阶段和衰退阶段.不同阶段具有明显不同的信息量(信息熵),信息熵为最大值阶段也就是古群落最复杂、最无序的顶极阶段.为此,可利用这一特性对地层进行高精度的划分和对比.经研究,初步总结出5条判别古群落演替不同阶段的基本原则:①地层层序率原则;②生物演进原则;③信息熵最大原则;④物种多样性指数呈对数正态分布原则;⑤古群落取代原则.在以川东华蓥山地区茅口期腕足动物群落演替分析的实例中,选择了4个统计量作为计算反映古群落结构特征信息熵的参数,即物种多样性指数(d)、物种个体平均大小(g)、物种生物量(s)及物种平均凸度(t),对两个古群落不同演替阶段的信息熵进行了计算和讨论,指出本地区茅口组地层分为上下两段,下段还可以分为3个亚段.同时发现在没有突发事件的影响下,古群落演替以衰退阶段历时最长,大约是顶极阶段的6～8倍.     

Dynamics of Saxothuringian subduction channel/wedge constrained by phase‐equilibria modelling and micro‐fabric analysis

Subduction and exhumation dynamics can be investigated through analysis of metamorphic and deformational evolution of associated high‐grade rocks. The Erzgebirge anticline, which forms at the boundary between the Saxothuringian and Teplá‐Barrandian domains of the Bohemian Massif, provides a useful study area for these processes owing to the occurrence of numerous meta‐basites preserving eclogite facies assemblages, and coesite and diamond bearing quartzofeldspathic lithologies indicating subduction to deep mantle depths. The prograde and retrograde evolution of meta‐basite from the Czech portion of the Erzgebirge anticline has been constrained through a combination of thermodynamic modelling and conventional thermobarometry. Garnet growth zoning indicates that the rocks underwent burial and heating to peak conditions of 2.6 GPa and at least 615 °C. Initial exhumation occurred with concurrent cooling and decompression resulting in the growth of amphibole and zoisite poikiloblasts overgrowing and including the eclogite facies assemblage. The development of clinopyroxene–plagioclase–amphibole symplectites after omphacite and Al‐rich rims on matrix amphibole indicate later heating at the base of the lower crust. Omphacite microstructures, in particular grain size analysis and lattice‐preferred orientations, indicate that the prograde evolution was characterized by a constrictional strain geometry transitioning into plane strain and oblate fabrics during exhumation. The initial constrictional strain pattern is interpreted as being controlled by competing slab pull and crustal buoyancy forces leading to necking of the subducting slab. The transition to plane strain and flattening geometries represents transfer of material from the subducting lithosphere into a subduction channel, break‐off of the dense slab and rebound of the buoyant crustal material.     

基于热力学过程的渤海海冰生消模型

为了对渤海海冰生消问题进行模拟,基于三维自由水面垂向分层动网格的Euler-Lagrangian模式,采用VC（Vertex-Centered）方式的非结构化有限体积方法离散三维浅水方程组,模拟渤海的水流运动过程。以此水动力场为背景,引入热力学过程的影响,对渤海海域的冬季结冰过程进行模拟,建立了海冰生消模型。其中热力学参数主要包括大气温度、相对湿度、风场特征、太阳辐射、感热通量系数以及潜热通量系数。以渤海2011/2012年常冰年的结冰过程为例,将各个热力学参数对冰情影响的敏感性进行分析,对模型进行了验证。结果表明,感热与潜热系数是对冰情影响最敏感的一项,即当感热和潜热通量系数仅减小了0.000 2后,其海冰的最大厚度就减小了15 cm。最后,通过连续实测的水动力数据与2009/2010年冬季的典型海冰灾害过程再一次对模型进行了验证,充分说明了模型具有较高的精确性、稳定性与实用性。