Influence of the Boreal Summer Intraseasonal Oscillation on Extreme Temperature Events in the Northern Hemisphere

The impact of the boreal summer intraseasonal oscillation (BSISO) on extreme hot and cool events was investigated, by analyzing the observed and reanalysis data for the period from 1983 to 2012. It is found that the frequency of the extreme events in middle and high latitudes is significantly modulated by the BSISO convection in the tropics, with a 3–9-day lag. During phases 1 and 2 when the BSISO positive rainfall anomaly is primarily located over a northwest–southeast oriented belt extending from India to Maritime Continent and a negative rainfall anomaly appears in western North Pacific, the frequency of extreme hot events is 40% more than the frequency of non-extreme hot events. Most noticeable increase appears in midlatitude North Pacific (north of 40°N) and higher-latitude polar region.Two physical mechanisms are primarily responsible for the change of the extreme frequency. First, an upper-tropospheric Rossby wave train (due to the wave energy propagation) is generated in response to a negative heating anomaly over tropical western North Pacific in phases 1 and 2. This wave train consists of a strong high pressure anomaly center northeast of Japan, a weak low pressure anomaly center over Alaska, and a strong high pressure anomaly center over the western coast of United States. Easterly anomalies to the south of the two strong midlatitude high pressure centers weaken the climatological subtropical jet along 40°N, which is accompanied by anomalous subsidence and warming in North Pacific north of 40°N. Second, an enhanced monsoonal heating over South Asia and East Asia sets up a transverse monsoonal overturning circulation, with large-scale ascending (descending) anomalies over tropical Indian (Pacific) Ocean. Both the processes favor more frequent extreme hot events in higher-latitude Northern Hemisphere. An anomalous atmospheric general circulation model is used to confirm the tropical heating effect.     

A study on the reaction kinetics of mineral surface adsorption in mix system

The experimental results on adsorption of ions pb²⁺, Zn²⁺ and Ag⁺ onto mineral surfaces in a mix system show that the reaction kinetics of adions adsorbed onto mineral surfaces was mainly controlled by their diffusion rates in solution. The concentration variations can be fit for the second-order rate equation with good determined coefficients r = 0.800 5—0.979 7. In the near neutral solution, the concentration of exchanged ions K⁺ and Na⁺ related to reaction time can be described by the fint-order rate equation with r = 0.855 7–0.997 7. Meanwhile, the complex diffusionexchange rate equation is suitable for describing the ca^{2 +} concentration variation, as ions Pb^{2 +} and Zn²⁺ were adions. Experimental data show that the amount of ions K⁺, Na⁺and Ca²⁺ release is much more than that of adion decrement in solution. This fact may suggest that the complexstion reaction of adions Pb²⁺, Z²⁺ and Ag⁺ with the mineral surfaces was the major reaction process while adions were not entering the phyllosilicate interlayers or CaCO₃ lattice to exchange the ions K⁺, Na⁺ and Ca²⁺ at room temperature. Project supported by the National Natural Science Foundation of China (Grant No. 49773206) and the Natural Science Foundation of Guangdong Province (Grant No. 960504)     

北大西洋涛动指数变化与北半球冬季阻塞活动

线性回归分析表明北大西洋涛动(NAO)主要与大西洋、欧洲及乌拉尔山地区阻塞的频率和强度的变化存在显著相关关系.在NAO负位相时期阻塞活动在大西洋地区较为频繁且强度较强,正位相时期大西洋地区阻塞活动减少,强度减弱,而欧洲阻塞加强,频率增加,同时乌拉尔山地区的阻塞活动也显著减少.NAO正指数的增强和减弱对应于大西洋和欧洲阻...     

矿物界面作用与环境工程材料

矿物水界面作用是环境地球化学研究的基础,它控制着世界淡水质量、土壤发生与发展、表生地质作用中元素迁移与富集等过程,是矿物环境工程材料的理论基础［１］。这是因为矿物水界面作用发生于矿物表面,许多环境工程材料是通过材料表面吸附（或共沉淀）作用去清除水...     

全液压坑道钻机故障预测与诊断的现代化技术探讨

针对煤炭企业广泛使用的全液压坑道钻机现场运行状况,剖析了全液压坑道钻机的故障机理和特点,研究用现代科学技术对全液压坑道钻机故障进行预测与诊断的技术方法,探讨了各种最新技术方法的可行性与适用性,并指出了今后的发展方向。     

一次冰雹风暴的CINRAD/SA产品分析

分析了2002年9月27日发生在山东东阿附近一次冰雹风暴发生、发展各阶段新一代天气雷达CINRAD/SA反射率、平均径向速度等产品的演变过程。在风暴中, 观测到了低层前侧入流缺口、有界弱回波区 (BWER)、中气旋 (M) 等超级单体风暴的特征。中气旋在风暴中维持了约90 min, 通过连续时次各仰角高度风暴相对速度产品的分析, 揭示了中气旋发生、发展和消亡的过程。分析表明风暴跟踪信息 (STI)、冰雹指数 (HI)、垂直积分液态含水量 (VIL)、中气旋 (M) 等产品对冰雹有较好的识别和预报能力。     

中国黄土的平均化学成分:上部大陆地壳的一种典型代表

本文通过对黄河中游地区马兰黄土的大面积野外实地考察,系统采样和室内分析测试,并采用质量加权平均的计算方法,给出了较为准确的中国黄土平均化学成分数据。中国黄土相对于下地壳和全地壳较富大离子半径的亲石元素而贫亲铁元素;与上部大陆地壳相比,中国黄土除相对较富Ca、B而贫Na、Nb外,其余绝大多数化学元素的丰度均非常接近甚至几乎相等。由此表明,中国黄土确属典型的上部大陆地壳物质,它不仅为暴露的上部大陆地壳提供了一种理想的天然平均样品,而且中国黄土的平均化学成分完全可以作为上部大陆地壳化学成分的代表而加以应用。     

基于图的语义室内导航模型构建研究

室内空间模型是室内导航的基础和关键所在,针对当前多数室内空间模型在建模过程中只考虑部分导航相关的影响因素,适用范围有限这一问题,结合室内导航特点,综合考虑用户室内移动特征、几何和语义信息表达、路径规划效率3个方面的建模影响因素,提出一种基于图的语义室内导航模型。基于图论的方法构建室内导航概念模型,然后在概念模型的基础上提出具体的几何图模型构建方法和语义信息表达方式,设计图模型中节点和边的数据结构,最后研究将该模型用于不同情景下室内路径规划的具体流程。     

顾及海底地形非线性项的最小二乘配置反演方法

针对目前常用的反演海底地形方法主要考虑海底地形和卫星测高重力数据线性趋势项而忽略非线性项影响现状,提出了顾及海底地形非线性项的最小二乘配置反演方法.选择日本海某海域作为目标海区,利用卫星测高重力异常和重力异常垂直梯度数据作为输入源进行了方法试算并构建了相应的海深模型,然后以实际船测海深作为外部检核参考,评估了反演模型效...