基于积温效应的华中电网电力负荷预测

利用2011—2015年5—9月华中4省河南、湖北、湖南、江西逐日日用电量、日峰负荷、日谷负荷与同期气象数据,探讨炎热天气过程对电力负荷的影响特征,并分别对4省建立基于积温热累积效应的电力负荷预测模型。结果表明:持续3d以上的炎热天气过程对电力负荷增长影响显著,其中湖北的电力负荷增量最大;当气温大于等于积温热累积效应的气温临界值时,对电力负荷增长有显著影响,其中湖南的日平均气温、日最高气温、日最低气温的初始敏感值分别为31℃、36℃、27℃,强敏感值分别为32℃、39℃、29℃;建立基于积温热累积效应的电力气象负荷多元回归预测模型,经2016年5—9月应用检验,华中4省的平均相对误差均控制在5%以内,根据具体天气情况进行适当订正,对国家电网公司华中分部电力调度具有参考价值。     

广西1998/1999年秋冬春异常干旱诊断分析

对广西１９９８ 年秋至１９９９ 年春出现的大范围干旱伴高温的异常天气进行了诊断分析, 发现厄尔尼诺与拉尼娜事件是导致广西气候异常的重要气候背景, 入侵广西的冷空气异常偏弱, 高原高度场偏高, 印缅槽偏弱, 副热带高压持续偏强, 热带气旋影响偏少, 强度偏弱, 是导致广西１９９８年秋至１９９９年春罕见的长时间高温、少雨、异常干旱的主要原因。     

石家庄春季一次气温预报失误原因探讨

在仔细分析大气环流背景、物理量场、实况资料以及数值预报产品检验的基础上,总结了2011年4月15日石家庄市区一次气温预报失误的经验教训:此次气温预报失败,主要是对地面高压移动位置预报出现偏差,东风影响的时间比预期偏晚,未能考虑西风造成的“焚风”效应.分析中还发现,在地面气温预报中,除注意高空系统及850 hPa变温外,对垂直运动也应着重考虑;西风分量大小的变化与气温的升降趋势一致;地面东风开始时间与地面气温由高到低的转折时间一致;T639 10 m风场数值预报产品具有一定的准确度,为今后类似情况下的气温预报提供了一定的参考.     

小震群序列类型判定方法研究的现状及相关问题研究的趋势

小震群地震活动经常发生,对其可能类型的快速判别,即对正在活动的小震群,究竟是"大震"的前震序列,还是并不伴有大震发生的一般性小震群的快速判别,对减轻地震灾害和维护社会稳定具有重要的现实意义.本文总结归纳了小震群序列类型判别方法研究的现状和存在的问题,并对震群序列类型判别研究的趋势进行了初步阐述.     

Experimental investigation on seismic behavior of scoured bridge pier with pile foundation

This study investigated the seismic performance and soil‐structure interaction of a scoured bridge models with pile foundation by shaking table tests using a biaxial laminar shear box. The bridge pier model with pile foundation comprised a lumped mass representing the superstructure, a steel pier, and a footing supported by a single aluminum pile within dry silica sand. End of the pile was fixed at the bottom of the shear box to simulate the scenario that the pile was embedded in a firm stratum of rock. The bridge pier model was subjected to one‐directional shakes, including white noise and earthquake records. The performance of the bridge pier model with pile foundation was discussed for different scoured conditions. It is found that the moment demand of pile increases with the increase of scoured depth whereas the moment demand of the bridge pier decreases, and this transition may induce the bridge failure mechanism transform from pier to pile. The seismic demand on scoured pile foundations may be underestimated and misinterpreted to a certain degree. When evaluating the system damping ratio with SSI, the system response may not be significantly changed even if the soil viscous damping contribution is varied. Copyright © 2014 John Wiley & Sons, Ltd.     

韶山煤田荷田向斜的发现及研究意义

逐一剖析了以往地质资料对荷田含煤区的地质构造解释方案，再现了不同的构造解释方案对应着不同的勘查工作价值，论述了荷田向斜的推断依据和方法，依此提出了湖南今后开展“三下”找煤的重点区。     

Can reanalysis datasets describe the persistent temperature and precipitation extremes over China?

This study analyzes the impact of anthropogenic climate change in the hydroclimatology of Senegal with a focus over the lake of Guiers basin for the middle (2041–2060) and late twenty-first century (2080–2099). To this end, high-resolution multimodel ensemble based on regional climate model experiments considering two Representative Concentration Pathways (RCP4.5 and RCP8.5) is used. The results indicate that an elevated warming, leading to substantial increase of atmospheric water demand, is projected over the whole of Senegal. In the Lake basin, these increases in potential evapotranspiration (PE) range between 10 and 25 % in the near future and for RCP4.5 while for the far future and RCP8.5, they exceed 50 %. In addition, mean precipitation unveils contrasting changes with wetter (10 to 25 % more) conditions by the middle of the century and drier conditions (more than 50 %) during the late twenty-first century. Such changes cause more/less evapotranspiration and soil moisture respectively during the two future periods. Furthermore, surface runoff shows a tendency to increase in most areas amid few locations including the Lake basin with substantial reduction. Finally, it is found that while semi-arid climates develop in the RCP4.5 scenario, generalized arid conditions prevail over the whole Senegal for RCP8.5. It is thus evident that these future climate conditions substantially threaten freshwater availability for the country and irrigated cropping over the Lake basin. Therefore, strong governmental politics are needed to help design response options to cope with the challenges posed by the projected climate change for the country.

     

地震大小的度量

The paper begins with a brief review of the research history of earthquake size measurement. On this basis, the author pointed out the following points： ① In recent decades, ML, mb （mH ）, Ms magnitude scales are widely used as measures of earthquake size. However, these magnitude scales have a deficiency of ＂overgeneralization＂ and ＂magnitude saturation＂. Moreover, since they do not fully take into account the regional difference of seismic attenuation, especially the difference of site effects on the amplification of ground motion, these magnitude scales are but inaccurate measures of earthquake size. ② Seismic moment M0 not only has clear physical meaning, but also overcomes the deficiencies existing in ML, mb （mB ） and Ms magnitude scales, so it is the most suitable physical quantity for measuring earthquake size scientifically. In order to continue to use the term ＂magnitude＂, Kanamori defined the moment magnitude scale Act. Although its prerequisite assumptions remain to be studied, it is still a reasonable scale used as a measure of the relative size of an earthquake. ③ For measuring the earthquake size more scientifically, we must make full use of a large amount of waveform data from modern regional digital seismograph networks, strengthen the research on seismic wave attenuation characteristics, site effect, calculation of source parameters and the related scaling relations. In improving the measurement methods for ML, mb （mB ） and Ms magnitude, we should focus on the improvement of Mw scale and carry forward the work as gradually taking Mw magnitude scale as the uniform physical quantity to measure the relative size of earthquakes, so as to lay a more solid foundation for research in earthquake science and earthquake prediction.     

Modal-based ground motion selection procedure for nonlinear response time history analysis of high-rise buildings

The selection of representative input ground motions (IGMs) is important for a proper nonlinear response time history analysis (NLRHA) of modern structures. The prevailing IGM selection procedure requires that the response spectra of selected ground motions are matched with the code-specified design spectra, while the effect of the frequency contents combination in the time domain on the multimode interactions is not considered. Ignoring the effect of the frequency contents combination in the time domain of IGMs may cause significant variations in the analysis results for selected IGMs, although they are matched to the same design spectrum. In this paper, a modal-based ground motion selection (MGMS) procedure is proposed as a supplement to spectrum matching-based IGM selection procedures for selecting proper IGMs that can sufficiently induce the multimode interactions. In the proposed procedure, three equivalent single-degree-of-freedom (ESDOF) systems are developed by pushover analysis. NLRHA is then conducted for these ESDOF systems with a set of 20 seed IGMs chosen by the spectrum-matching–based selection procedure. Finally, seven IGMs are selected from the seed IGMs for NLRHA in the full structural model. To verify MGMS, seismic demands of high-rise buildings were computed by NLRHA with seven MGMS-selected IGMs, seven IGMs with closest spectrum matching, and groups of seven randomly selected IGMs derived from three different sets of 20 seed IGMs. The computed seismic demands with MGMS-IGMs show very good agreement with the mean demands determined using the whole set of seed IGMs, while the deviation is much lesser compared with those groups of randomly selected IGMs.     

Using Long-Period Body Wave to Inverse Moment Tensors of the M_S6.8 Jiashi,Xinjiang Earthquake in 2003 and the Moderate and Small Earthquakes before and after It

An Ms6.8 strong earthquake took place in Jiashi, Xinjiang on February 24 of 2003. The digital wave form data recorded in Kashi and Wushi stations are selected to inverse the moment tensor solutions for the strong earthquake and the moderate and small earthquakes before and after it （ 108 earthquakes in 2001 - 2004）. 67 focal mechanism solutions have been calculated, and the results agree with those from Harvard University and USGS. The analysis reveals that before the strong earthquake, the moderate and small earthquake distribution was dispersed, and after the event the distribution was mainly concentrated around the strong earthquake. Before the strong earthquake, the seismic faults of the mid and small events had the character of strike-slip and normal faulting, and after the event, they exhibit strike-slip and thrust faulting. The region is dominated by near-NS horizontal compression from the southern block after the strong earthquake.