信阳市渔业气象服务效益分析

对信阳市南湾水库渔业气象服务效益调查分析结果表明:在亲鱼培育、种苗繁殖、苗种培育、成鱼养殖、捕捞等主要生产阶段,成鱼养殖阶段服务效益最大,为21.98万元;繁殖、亲鱼培育阶段服务效益占该阶段渔业总产值的比例分别列第一和第二,说明这两个生产阶段气象服务尤为重要.由于对渔业气象服务还不够重视,加之还缺乏渔业与气象条件关系的研究,目前渔业气象服务层次较低,渔业气象服务效益贡献率也较低.     

利用EXCEL软件进行线性回归分析

介绍了EXCEL数据处理软件在一元和多元线性回归分析中的应用方法及实现技巧。     

基于SPEI的中国西南地区1961-2012年干旱变化特征分析

利用1961—2012年中国西南地区86个气象站逐月降水量和平均气温资料,引入一个新的干旱指数——标准化降水蒸散指数(SPEI)作为干旱等级划分指标,研究了1961—2012年该地区不同时间尺度干旱的变化特征。结果表明:该地区12个月尺度干旱频率在云贵交界区呈显著增加趋势,其他区域变化不显著且不一致;少雨期(11—4月)6个月尺度干旱频率在全区显著增加,而在多雨期(5—10月)大部分区域干旱频率呈缓慢减少趋势,减少最明显的区域在四川南部;3个月尺度干旱频率在春季变化不明显,在秋季和冬季显著增加,其中2000—2012年的增加趋势尤为显著,干旱化趋势严重。     

天山南麓雷暴日短期预报研究

利用阿克苏及邻近地区12个气象站1980—2013年雷暴资料,以及同期高空资料,统计了各站年均雷暴日数,对发生区域雷暴天气的环流形势进行分类,归纳出各型的入型指标。通过逐步回归法,建立阿克苏及邻近地区区域雷暴概率回归预报模型,并对2013年进行试预报。结果表明:(1)阿克苏及邻近地区区域雷暴的影响系统主要分为4类:巴湖低槽型、急流型、西北气流型和温度槽型。(2)对2002—2012年5—9月(共1683 d)历史资料进行判别,满足入型条件的样本数为876 d,消空率为48%;对2013年5—9月(共153 d)历史资料进行判别,入型样本数为80 d,消空率为48%。(3)对2002—2012年5—9月所有入型样本进行回代检验,平均准确率为72.0%(平均TS评分为30.1%);对2013年5—9月所有入型样本进行试预报,平均准确率为63.2%(平均TS评分为28.2%)。     

新型随机地震动模型

在研究结构的随机地震反应时，要用大量的符合场地条件的地震记录作为输入数据。但强震历史记录却不是每个地区都有的，因此根据符合场地条件的现有地震记录建立随机地震动模型具有重要意义。本文利用中国抗震规范2001版修正选取的样本波作为目标波，考虑了幅值和频率的双重非平稳性，建立了新型随机地震动模型——改进的时变ARMA模型随机地震动模型。通过使用残差的卡方检验法，对多种非平稳ARMA模型生成的模拟波进行检验；同时又比较丁模拟波与目标波的功率谱密度图和反应谱图。结果证明：此法能够更精确地反映不同场地条件地震动的频谱和幅值的真实内容，从而建立符合目标场地条件的更为有效的模拟地震动，为相关研究与工程设计架起一座桥梁。     

Research and Practice on the Crustal Deformation Mobile Monitoring Network Layout in the Hydropower Station Reservoir Area

According to the construction project of the crustal deformation mobile monitoring network in the cascade hydropower stations built in the lower reaches of Jinsha River,this paper analyzes the design ideas and layout principles of crustal deformation mobile monitoring used in the monitoring of reservoir induced earthquakes. This paper introduces three types of monitoring networks used in the Xiluodu reservoir and Xiangjiaba reservoir, as well as the work already undertaken,in order to provide a kind of reference for the related engineering construction and comprehensive monitoring of reservoir induced earthquakes.     

Role of reservoir regulation and groundwater feedback in a simulated ground-soil-vegetation continuum: A long-term regional scale analysis

The regional terrestrial water cycle is strongly altered by human activities. Among them, reservoir regulation is a way to spatially and temporally allocate water resources in a basin for multi-purposes. However, it is still not sufficiently understood how reservoir regulation modifies the regional terrestrial- and subsequently, the atmospheric water cycle. To address this question, the representation of reservoir regulation into the terrestrial component of fully coupled regional Earth system models is required. In this study, an existing process-based reservoir network module is implemented into NOAH-HMS, that is, the terrestrial component of an atmospheric–hydrologic modelling system, namely, the WRF-HMS. It allows to quantitatively differentiate role of reservoir regulation and of groundwater feedback in a simulated ground-soil-vegetation continuum. Our study focuses on the Poyang Lake basin, where the largest freshwater lake of China and reservoirs of different sizes are located. As compared to streamflow observations, the newly extended NOAH-HMS slightly improves the streamflow and streamflow duration curves simulation for the Poyang Lake basin for the period 1979–1986. The inclusion of reservoir regulation leads to major changes in the simulated groundwater recharges and evaporation from reservoirs at local scale, but has minor effects on the simulated soil moisture and surface runoff at basin scale. The performed groundwater feedback sensitivity analysis shows that the strength of the groundwater feedback is not altered by the consideration of reservoir regulation. Furthermore, both reservoir regulation and groundwater feedback modify the partitioning of the simulated evapotranspiration, thus affecting the atmospheric water cycle in the Poyang Lake region. This finding motivates future research with our extended fully coupled atmospheric–hydrologic modelling system by the community.     

Characteristics and method of synthesis seismic wave based on wavelet reconstruction

A novel method of synthesizing seismic wave using wavelet reconstruction is proposed and compared with the traditional method of using theory of Fourier transform. By adjusting the frequency band energy and taking it as criterion, the formula of synthesizing seismic wave is deduced. Using the design parameters specified in Chinese Seismic Design Code for buildings, seismic waves are synthesized. Moreover, the method of selecting wavelet bases in synthesizing seismic wave and the influence of the damping ratio on synthesizing results are analyzed. The results show that the synthesis seismic waves using wavelet bases can represent the characteristics of the seismic wave as well as the ground characteristic period, and have good time-frequency non-stationary.     

层状地基端承桩扭转动力阻抗研究

本文采用Novak薄层法推导粘弹性地基的扭转动力阻抗,并将其用于考虑桩土相互作用的单桩扭转动力阻抗,又通过传递矩阵法将此公式推广到求取层状地基单桩扭转动力阻抗。而且本文以工程中常用的端承桩为例,推导了层状地基中端承桩扭转动力阻抗的简化计算公式。根据此公式,分析了频率、上覆软土层厚度、上覆软土层刚度等因素对单桩扭转动力阻抗的影响,分析结果表明,随着振动频率提高,层状地基中端承单桩的扭转动力阻抗的实部有缓慢下降的趋势,而虚部则增大;随着上覆土层厚度的增加,层状地基中端承单桩的扭转动力阻抗的实部和虚部均减小;随着上覆土层刚度的减小,层状地基中端承单桩的扭转动力阻抗的实部减小,虚部在低频段减小,而在较高频率段则增大。     

A non-linear regularized constrained impedance inversion

Inversion for seismic impedance is an inherently complicated problem. It is ill‐posed and band‐limited. Thus the inversion results are non‐unique and the process is unstable. Combining regularization with constraints using sonic and density log data can help to reduce these problems. To achieve this, we developed an inversion method by constructing a new objective function, including edge‐preserving regularization and a soft constraint based on a Markov random field. The method includes the selection of proper initial values of the regularization parameters by a statistical method, and it adaptively adjusts the regularization parameters by the maximum likelihood method in a fast simulated‐annealing procedure to improve the inversion result and the convergence speed. Moreover, the method uses two kinds of regularization parameter: a ‘weighting factor’λ and a ‘scaling parameter’δ. We tested the method on both synthetic and field data examples. Tests on 2D synthetic data indicate that the inversion results, especially the aspects of the discontinuity, are significantly different for different regularization functions. The initial values of the regularization parameters are either too large or too small to avoid either an unstable or an over‐smoothed result, and they affect the convergence speed. When selecting the initial values of λ, the type of the regularization function should be considered. The results obtained by constant regularization parameters are smoother than those obtained by adaptively adjusting the regularization parameters. The inversion results of the field data provide more detailed information about the layers, and they match the impedance curves calculated from the well logs at the three wells, over most portions of the curves.