广西区域极端特大暴雨成因个例分析

利用常规观测资料、FY-2E卫星观测资料、雷达探测资料以及自动站雨量资料等,对2010年6月28日广西极端特大暴雨过程进行分析;结果表明：①暴雨灾害具有区域小、降雨时段集中、过程雨量大、短历时降雨强及引发次生灾害特别重等特点;②亚欧中高纬度500 hPa呈两脊一槽型、200 hPa南亚高压脊线贯穿广西上空及西南季风活跃是暴雨的环流背景;高空低涡、地面干线是主要天气系统配置,属低涡暴雨型;③强不稳定能量及层结的存在、850 hPa以下低层辐合、700 hPa附近明显涡旋、整层大气上升运动、850 hPa以下层高湿及水汽强烈辐合是主要物理量特征;④中尺度低压、低涡及气流辐合等是中尺度对流触发条件.FY-2E红外云图上对流云团生成、合并对强降雨有重要指示意义,暴雨发生在云团合并发展阶段,FY-2E的TBB值小于200 K可以作为短历时强降雨的指标.低质心雷达回波产生的列车效应和地形作用是造成强降雨的重要因素,低层辐合、高层辐散导致的强烈上升运动,有利于强对流的发展与维持.     

Making journal articles ‘live’: turning academic writing into scientific dialog

Web 2.0 services and social networking offer possibilities to transform academic publishing to facilitate scientific dialogue. We present ‘The Live Paper’ in this editorial as a concept to consider how to leverage existing web technologies to produce rich, omnidirectional, and interactive narratives on research. Following the format of a traditional research report we describe and discuss how to enrich research reports utilizing various types of analytical tools, data, and web services in a published paper embedded in evolving scientific discourse. We also consider how the live papers would influence the practice, culture, and economy of academic research. We conclude that geospatial researchers have an opportunity to lead this development towards richer and more open ways of communicating our findings. The technology and infrastructure to do so exist today, but several barriers remain.     

北京石花洞石笋微层层面有机物质的形成时间及机理初探

通过对北京石花洞滴水水溶性有机碳(DOC)近一个水文年的观测,发现不同点滴水DOC浓度均表现出明显的季节性变化,7月中旬均有一个大的主峰出现。初步说明中国北方石笋微层的层面物质沉积于7月雨季,主要来源于大的雨量对土壤中有机质的淋溶;洞穴顶板较薄的滴水点在5月和8月有明显的DOC次峰,可能与石笋亚年层形成有关。     

新安县引畛济涧隧洞工程小导管注浆技术

新安县引畛济涧工程3号竖井开挖深度大,地下水极其丰富,存在涌水突水情况。采取小导管注浆措施进行涌水点2倍洞径范围内封堵渗涌水,浆液采用水泥水玻璃双浆液。注浆封堵加固一环开挖掘进一环,成功地完成了隧洞的开挖掘进。为类似工程施工提供了经验。     

Forecasting the ionospheric f0F2 parameter one hour ahead using a support vector machine technique

This paper proposes a method for forecasting the ionospheric critical frequency, f₀F₂, 1 h in advance, using the support vector machine (SVM) approach. The inputs to the SVM network are the time of day, seasonal information, 2 month running mean sunspot number (R2), 3 day running mean of the 3 h planetary magnetic ap index, the solar zenith angle, the present value f₀F₂(t) and its first and second increments, the observation of f₀F₂ at t?23 h, the 30-day mean value at time, t, f_mF₂ (t) and the previous 30 day running mean of f₀F₂ at t?23 h f_mF₂(t?23). The output is the predicted f₀F₂ 1 h ahead. The network is trained to use the ionospheric sounding data at Haikou, Guangzhou, Chongqing, Lanzhou, Beijing, Changchun and Manzhouli stations at high and low solar activities. The performance of the SVM model was verified with observed data. It is shown that the predicted f₀F₂ has good agreement with the observed f₀F₂. The performance of the SVM model is superior to that of the autocorrelation and persistence models, and that it is comparable to that of the neural network model.     

洱海沉积物孔隙水中溶解有机质的三维荧光光谱特征

文章应用三维荧光光谱技术对洱海沉积物孔隙水中的溶解有机质进行了研究。结果表明,所有样品均含有4个明显的荧光峰,其中A和C为类腐殖酸荧光,B和D为类蛋白荧光。荧光强度在沉积物-水界面特别强,在1cm处急剧下降,之后随着沉积深度呈上升趋势。孔隙水溶解有机质均具有强的类蛋白荧光,揭示了溶解有机质中含有大量色氨酸、酪氨酸等芳环结构的类蛋白物质,并且在早期成岩过程中随着沉积深度呈积累趋势;类蛋白荧光与类腐殖酸荧光之间具有一定的相关关系,r(A,C)值在0.94-1.79之间,随着沉积深度逐渐下降,r(D,B)值在0.9-1.75之间,与r(A,C)值极为接近,且随着沉积深度有着类似的变化趋势,说明在洱海沉积物孔隙水中,r(D,B)与r(A,C)之间具有一定的相关性。     

洱海沉积物化学元素与古气候演化

测定了洱海沉积物中常量和微量元素的含量,利用因子分析方法,识别了控制沉积物化学组成的三个主要因子：流域侵蚀因子、早期成岩因子和湖 内生碳酸钙了。进一步 研究还发现,流域了和湖泊内生碳酸钙沉淀因子的因子得分曲线作为气候干湿和冷暖变化的代用曲线。从而为古气候重建提供了一条有效的新途径。结合沉积的柱＾２１０Ｐｂ和＾１３７Ｃ计年结果,初步评价了６００多年来洱海区域气候及环境演化历史,提示他该区暖干与冷湿相     

Equivalent damping of SDOF structure with Maxwell damper

To predict the maximum earthquake response of an SDOF structure with a Maxwell fluid damper or supplemental brace-viscous damper system using the seismic design response spectrum technique, a new approach is presented to determine the first- and second-order equivalent viscous damping and stiffness, the peak responses, and the damper force of the above structure. Based on the fact that the dynamic characteristics of a general linear viscoelastically damped structure are fully determined by its free vibration properties and the relaxation time constants of a Maxwell fluid damper and supplemental brace-viscous damper system in engineering practice are all small, the method of improved multiple time scales and the equivalent criterion in which all free vibration properties are the same are used to obtain the first- and second-order equivalent viscous damping and stiffness of the above structure in closed form. The accuracy of the proposed method is higher and significantly better than that of the modal strain energy method. Furthermore, in the parametric range of the requirements of the Chinese "Code for Seismic Design of Buildings", the error of the proposed second-order equivalent system for the above-mentioned engineering structure is not more than 0.5%.     

BIOGEOCHEMICAL MECHANISM OF POSTDEPOSITIONAL MIGRATION OF Fe AND Mn IN LAKE AHA, CHINA

I.INTRODUCTIONLakeAhaisamedium--sizedartificialreservoirwithseasonallyanoxichypolirnnion,andawaterresourceofGuizhouProvince,China,builtin1958,workedin1960andexpandedin1982.Ithasadrainagebasinof190kmZwithaverageannualtemperatureof15.3tandprecipitationof1109rum.Openplantcover,containiflgshrubandgrass,surroundsthelake,andsialliticandstfeteyellowsoilisdevelopedonPe~ianlimestoneandcoallayer,meanwhile,OThisprojectwassupportedbytheNationalNaturalaudienceFOundationofChinaandtheaudienceFOund…