台风尼伯特(1601)残留低压局地大暴雨成因分析

利用常规观气象观测资料、地面自动站资料、NCEP/FNL逐6h的1°×1°再分析资料、多普勒天气雷达和风廓线雷达资料及GPS-PWV资料等,对江苏南通2016年7月11日一次大暴雨到特大暴雨过程进行了分析。结果表明:(1)该过程发生在台风尼伯特(1601号)残留低压、高空冷涡低槽和副热带高压共同作用的背景下;台风残留低压北侧倒槽顶部大的气旋性曲率和高空槽前减压导致低层苏南附近α中尺度低压生成,台风残留低压并入该低压,使低压发展,气压梯度加大,气压梯度力做功使动能增大,导致低空西南急流形成,利于暴雨发生;α中尺度低压内先后有D1、D2和D3等3个β中尺度低涡生成,其中D3造成了南通地区的大暴雨,中心位于南通大学附近,最大雨强达151.2mm·h~(-1)。(2)南通地区对流风暴触发后,降水的凝结潜热释放增强了对流风暴内的上升运动,促使低空中尺度偏东急流和其左前侧β中尺度低涡D3的形成和发展;之后,中层干冷空气入侵加强了对流不稳定和垂直风切变,使D3右侧多个低质心的γ中尺度单体风暴强烈发展且受低空风影响移动缓慢,强降水得以持续和跃增。(3)风垂直切变突增时间较强降水出现峰值时间早约30min,以及多普勒天气雷达径向速度的低空辐合(辐散)较对流风暴的发展(减弱)明显提前,对临近预报有一定的参考意义。     

土壤中氡浓度检测及其影响因素

综合相关文献研究,通过工程实例介绍土壤中氡气浓度的检测方法,对检测结果进行统计学分析,根据分析结果探讨不同土壤中氡浓度差异及其影响因素。结果显示:土壤孔隙度是影响土壤中氡气浓度的关键因素。不同类型的表层土壤,孔隙度不同,所含氡气浓度也不同。当表层土壤为房渣土、填土时,土质夯实,孔隙率低,氡浓度含量较低;表层土壤为粉土、粉质粘土时,土质较均匀,土层较疏松,孔隙度略大,土壤氡浓度大于前者;表层土壤为粉砂、细砂时,土层更为疏松,土壤中孔隙度再次增大,氡在土壤中有大量的存储空间,所含的氡浓度最大。因此,土壤的孔隙度大小影响氡从地下向地表渗透析出的难易程度,孔隙度越大氡越容易渗透其中,浓度就越高。     

普通高中灾害地理教育课程:意蕴及校本构建

灾害地理教育主要培养学生对自然灾害的感受、理解以及人类与其理性相处和和谐共生的自觉意识和能力,为了便于灾害地理教育操作和实施,本文主要从三个维度,使学生理解自然灾害、环境与人类之间的关系,通过灾害地理教育课程校本建构,实现灾害知识接受学习和实践体验的无缝衔接,努力回答新时代灾害地理教育培养"什么样的人"这一问题。     

Shifting from homogeneous to heterogeneous surfaces in estimating terrestrial evapotranspiration: Review and perspectives

Terrestrial evapotranspiration(ET)is a crucial link between Earth’s water cycle and the surface energy budget.Accurate measurement and estimation remain a major challenge in geophysical,biological,and environmental studies.Pioneering work,represented by Dalton and Penman,and the development of theories and experiments on turbulent exchange in the atmospheric boundary layer(ABL),laid the foundation for mainstream methodologies in ET estimation.Since the 1990s,eddy covariance(EC)systems and satellite remote sensing have been widely applied from cold to tropical and from arid to humid regions.They cover water surfaces,wetlands,forests,croplands,grasslands,barelands,and urban areas,offering an exceptional number of reports on diverse ET processes.Surface nocturnal ET,hysteresis between ET and environmental forces,turbulence intermittency,island effects on heterogeneous surfaces,and phase transition between underlying surfaces are examples of reported new phenomena,posing theoretical and practical challenges to mainstream ET methodologies.Additionally,based on non-conventional theories,new methods have emerged,such as maximum entropy production and nonparametric approaches.Furthermore,high-frequency on-site observation and aerospace remote sensing technology in combination form multi-scale observations across plant stomata,leaves,plants,canopies,landscapes,and basins.This promotes an insightful understanding of diverse ET processes and synthesizes the common mechanisms of the processes between and across spatial and temporal scales.All the recent achievements in conception,model,and technology serve as the basis for breaking through the known difficulties in ET estimation.We expect that they will provide a rigorous,reliable scientific basis and experimental support to address theoretical arguments of global significance,such as the water-heat-carbon cycle,and solve practical needs of national importance,including agricultural irrigation and food security,precise management of water resources and eco-environmental protection,and regulation of the urban thermal environment and climate change adaptation.     

青海祁漫塔格成矿带与虎头崖铜铅锌多金属矿床有关的二长花岗岩体热年代学研究

虎头崖铜铅锌多金属矿区是青海祁漫塔格地区较为典型的兼具内接触带矽卡岩亚型和外接触带矽卡岩亚型矿化的矿区,其岩浆侵入活动强烈,不同时代含碳酸盐岩的地层出露多,铁铜锡钼铅锌等金属成矿元素组合复杂,找矿潜力巨大。本次研究依据岩体热年代学理论,即岩体总能量与其规模成正比,规模愈大的岩体其热能量愈高,热效应愈大,冷速率相应愈低。冷速率通过同一岩体不同矿物的封闭温度计算得出。选取虎头崖矿区黑云母和斜长石两种矿物进行Ar-Ar年龄测定,样品HTY002黑云母和斜长石~(40)Ar-~(39)Ar坪年龄分别为(233.6±2.2)Ma和(231.5±1.3)Ma,样品HTY016黑云母和斜长石~(40)Ar-~(39)Ar坪年龄分别为(229.6±2.3)Ma和(219.3±1.8)Ma,样品HTY019黑云母和斜长石~(40)Ar-~(39)Ar坪年龄分别为(224.7±2.6)Ma和(222.2±2.2)Ma,计算得到二长花岗岩冷速率分别为57.14℃/Ma、11.65℃/Ma、48.00℃/Ma。当侵入岩体的成分相近时,其侵位时的单位热能可能差别很小,而岩体的总能量与其规模是成正比的,所以不同规模岩体的总能量是有差别的,规模愈大的岩体其热能量也愈高,与围岩达到平衡所需的时间愈长,热效应愈大,冷速率相应愈低。针对不同样品和不同矿物计算虎头崖矿区二长花岗岩体冷速率比较接近,其冷速率相对较快(介于11~57℃/Ma),可知其热效应较大,具有一定的成矿潜力。     

Assessing the influence of assimilating radar-observed radial winds on the simulation of a tropical cyclone

Observations by Doppler weather radar are crucial for nowcasting and short-time forecasting of severe weather events as they bring in refined information of the atmosphere. However, due to the inevitable noises and non-meteorological signals, they cannot be assimilated straightforwardly into a numerical model. In the present study, assimilation of the radial component of wind velocity observed by two Doppler radars is performed in the numerical simulation of Supertyphoon Rammasun (2014) just before its landfall. After several quality-control steps, the radar-observed radial velocities are de-aliased, noise-reduced and assimilated into the model to improve initial conditions for the high-resolution simulation. Results show that only when using global background error covariance matrix can the observational increment be properly assimilated into the model, correcting large-scale background steering flow and yielding a simulated track close to the observed one. However, little improvement is found in simulating the TC core-scale structures by the assimilation of radar velocity as compared to the radar-observed flow, primarily due to the insufficient spatial resolution of the model that may lead to the incorrect representation of the TC core structure and the rejection of some core-region observations during the data assimilation procedure. Moreover, assimilation-induced asymmetries consume a certain portion of mean kinetic energy, preventing the simulated Rammasun from axisymmetrization and thus intensification as compared with the non-assimilated experiment.     

A Study of Near- and Super-Critical Fluids Using Diamond Anvil Cell and in-Situ FT-IR Spectroscopy

The phase relation and solution structure of water and NaCl aqueous solution have been observed and examined by using the hydrothermal diamond anvil cell (HDAC) at elevated temperatures and pressures and the in situ FT-IR spectroscopy. The temperature of observations ranges from 25 to 850° C and the pressure up to 10 or 30 kb. At first, we observed the phase transition process from halite+liquid+vapour (H+L+V) to L+H, then to L (or supercritical fluid, SCF), and another path: H+L+V? L+V? L (or SCF) in heating process. By means of the visual microscope, the authors found that in the L+V immiscibility field L+V exhibits an ordered structure, i.e. a large visual cluster of solvent around ions. The liquid phase is manifested by vapour bubbles. When phase transitions are observed, the authors examined their infrared spectra by using the FT-IR microscopy simultaneously. In the case of the phase transition from liquid (L) to liquid + vapor (L+V) immisciblity field of NaCl solutions, a sudden change (strong frequency shift) of infrared spectra of the aqueous solution is observed near the critical temperature of water as the temperature is raised from 25 to 650° C. The frequency of the maximum intensity of OH symmetric and asymmetric vibration varies with respect to temperature. The sharp peak of the OH stretching vibration of the maximum intensity appears in an interval from 300 to 400° C. It is indicated that the hydrogen bonding network is weakened and broken at last near the critical point of water, which causes the aqueous solution to become more associated. Besides, a pressure indicator (a mineral or compound) was introduced to the HDAC.     

中国周降雨量与相关海域周平均海面水温

应用旋转主成分分析和复变量莫莱特小波变换分析了1982～1995年中国境内实测周降雨量和1982～1994年美国环境预报中心周平均海面水温资料,研究其时空变化特征及其相互关系。结果表明:海面水温乃至降雨量的周年变化,主要源于太阳直射点在南北回归线之间的往复运动和海面云雾覆盖量及其相关联的季风周年变化;依降雨量的周年变化可将中国自然地分为12个降水区,从海气相互作用的角度来看其年际变化主要取决于太阳辐射强度、有效日照率和亚洲夏季风的年际变化;厄尔尼诺只对黄河河套北部和两广降水区年降雨量有较大影响;西太平洋暖池以东海面水温的年际变化仅对黄河河套北部年降雨量有一定影响。     

Research on auto-classification method of remote sensing images in mountainous areas—An application in Southwest of China

In mountainous areas, it is the undulant terrain, various types of geomorphic and land use that make the remote sensing images great metamorphism. Moreover, due to the elevation, there are many areas covered with shadow, clouds and snow that make the images more inaccurate. As a result, it would be very difficult to carry out auto-classification of RS images in these areas. The study took Southwest China as the case study area and the TM images, SPOT images as the basic information sources assisted by the auxiliary data of DEM, NDVI, topographical maps and soil maps to preprocess the images. After preprocessing by topographic correction and wiping off clouds, snow and shadows, all the image data were stacked together to form the images to be classified. Then, the research used segmentation technology and hierarchical method to extract the main types of land use in the area automatically. The results indicated that the qualitative accuracies of all types of land use extracted in Southwest China were above 90 percent, and the quantitative accuracies was above 86 percent. The goal of reducing workloads had been realized. Supported by the National Public Welfare Project on Environmental Protection (2007KYYW21), the Program of National Science and Technology research( 2006BAC01A01-05).     

潜式与离岸式人工岬头护滩作用和水交换特征比较

潜式人工岬头和离岸式人工岬头是两种改良式人工岬头,与传统人工岬头相比,它们对岸滩的保护效果稍弱,但能改善岬湾内的水交换。以北戴河西海滩养滩工程为研究对象,采用数值模拟的方法,对潜式岬头和离岸式岬头的护滩效果和改善水交换效果进行研究比较。首先建立岸线演变模型和物质输运模型,对工程后的岸线演变及水交换情况进行模拟。岸线演变的模拟结果表明,潜式岬头和离岸式岬头的护滩效果均较好,但潜式岬头后的岸线形状相比离岸式岬头后更为平滑。同时讨论海滩的侵蚀和淤积特性对潜式岬头和离岸式岬头的影响以及潮汐条件对冲淡时间的影响。与传统岬头相比,潜式岬头和离岸式岬头可以很好地减少岬后冲淡时间以及改善岬湾内水交换,而护滩效果只是稍有减弱。因此,潜式岬头和离岸式岬头都是改善岬湾水交换的有效工程措施。