唐山地震房屋倒塌率与烈度相关分析   总被引：2，自引：3，他引：2       下载免费PDF全文

杨哲  程家喻 《地震地质》1994,16(3):284-288

以街区和自然村为样本，通过唐山震害航片对１９４２个样本进行房屋倒塌率判读和分区统计，建立了房屋倒塌条烈度相关模型，分析了不同烈度区房倒率的频度展布特征。其模型可为大震应急及震害损失快速评估时烈度评定提供定量标准，频度分析结果可为震害预测提供量化依据  相似文献   

中国地区地磁异常静日（AQD）的初步分析          下载免费PDF全文

彭丰林  朱岗崑 《地球物理学报》1988,31(3):249-256

本文将G.M.Brown等人对离S_q电流体系焦点较远处台站的异常静日（AQD）的H分量分析,发展为对包括S_q电流体系焦点附近台站和Z、D分量在内的AQD分析。主要分析了中国五个地磁台D、H、Z三要素静日最大值和最小值出现时间的分布,及其季节变化和逐年变化规律。结果表明,D、Z也有和H类似的AQD现象,其出现的年频度,也有与太阳黑子数反相变化的趋势。在有三个多太阳周资料的佘山台,太阳极小年AQD(Z_max)出现的频度,和随后的太阳极大年的黑子数R呈近似线性的关系。最后,本文对今后我国开展变化磁场的分析研究提出了建议。  相似文献   

基于云量影像的日照百分率遥感集成模型     

施国萍  邱新法  曾燕  仇月萍 《遥感学报》2013,17(6):1508-1517

通过遥感影像云量数据和地面站点日照百分率观测数据建立遥感集成日照百分率模型,模拟遥感集成日照百分率的空间分布。基本思路是以空间尺度上的富余弥补时间尺度上的稀缺。云的移动是连续的,所以一幅云量遥感影像中,某一格网点周围一定区域范围内的云量都有可能对该点日照情况产生影响,因此对遥感总云量数据在日照轨迹内及云移动所经路径内重采样,能够更接近可照时段内云量的真实情况。然后按云量和日照百分率的负相关性,建立了日尺度的日照百分率遥感集成综合模型,实现对遥感集成日照百分率的模拟,完成日照百分率的遥感集成空间分布模拟图。结果表明：（1）重采样后的总云量克服了云量观测在时间上的局限性;（2）遥感集成日照百分率克服了气象站点空间上的局限性;（3）遥感集成日照百分率模型模拟精度相对插值法有显著的提高。  相似文献   

成都市二手房区域优势度的空间特征分析     

章霞  陈荣清  王志城 《测绘科学》2013,38(3):96-97,99

本文基于实地调查分析,将SPSS相关分析和GIS的空间分析结合对二手房选址进行研究,运用GIS空间分析的缓冲区分析、叠置分析等功能得出最佳二手房购买区位分布图,最终结果表明,目前成都市较好的二手房区域选择主要集中武侯、青羊和锦江区。研究成果对二手房的购买选择和二手房中介营销策略实施提供指导意义,对政府城市规划也有参考意义。  相似文献   

Problems with identifying the ‘8200‐year cold event’ in terrestrial records of the Atlantic seaboard: a case study from Dooagh,Achill Island,Ireland     

Katie Head  Chris S. M. Turney  Jon R. Pilcher  J. G. Palmer  M. G. L. Baillie 《第四纪科学杂志》2007,22(1):65-75

The Northern Hemisphere cooling event 8200 years ago is believed to represent the last known major freshwater pulse into the North Atlantic as a result of the final collapse of the North American Laurentide ice sheet. This pulse of water is generally believed to have occurred independently of orbital variations and provides an analogue for predicted increases in high‐latitude precipitation and ice melt as a result of anthropogenically driven future climate change. The precise timing, duration and magnitude of this event, however, are uncertain, with suggestions that the 100‐yr meltwater cooling formed part of a longer‐term cold period in the early Holocene. Here we undertook a multiproxy, high‐resolution investigation of a peat sequence at Dooagh, Achill Island, on the west coast of Ireland, to determine whether the 8200‐year cold event impacted upon the terrestrial vegetation immediately ‘downwind’ of the proposed changes in the North Atlantic. We find clear evidence for an oscillation in the early Holocene using various measures of pollen, indicating a disruption in the vegetation leading to a grassland‐dominated landscape, most probably driven by changes in precipitation rather than temperature. Radiocarbon dating was extremely problematic, however, with bulk peat samples systematically too young for the North Atlantic event, suggesting significant contamination from downward root penetration. The sustained disruption to vegetation over hundreds of years at Dooagh indicates the landscape was impacted by a long‐term cooling event in the early Holocene, and not the single century length 8200‐year meltwater event proposed in many other records in the North Atlantic region. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Impact of anthropogenic geochemical change and aquifer geology on groundwater phosphorus concentrations     

《Applied Geochemistry》2016

Geologic and geochemical variations across a 4200 km² area of south-central Wisconsin (USA) were used to examine their relationship to phosphorus concentrations in groundwater from more than four hundred private water supply wells. Surficial geology in the study area ranged from Cambrian sandstones to Ordovician dolomites. Groundwater phosphorus concentrations were higher in aquifers of older Cambrian age compared to the concentrations in aquifers of younger Cambrian and Ordovician age. Because iron concentrations were relatively low in these waters and agricultural land use was similar in all geologic regions, we propose that the differences in bedrock phosphorus and anthropogenic geochemical impacts explain the differences in phosphorus concentrations between aquifers. Within the older Cambrian aquifers, groundwater phosphorus concentrations were elevated in groundwater with higher nitrate-nitrogen concentrations. This finding is consistent with the presence of phosphorus within sediment in these strata and geologic conditions that weakly buffered pH reduction from anthropogenic acidification. In contrast, groundwater phosphorus concentrations in younger Cambrian and Ordovician aquifers were not elevated in samples with higher nitrate. Anthropogenic acidification in these carbonate-rich aquifers was neutralized through increased carbonate weathering, which led to higher groundwater calcium and alkalinity and would limit the dissolution of phosphate-rich minerals, such as apatite, where present. Low iron concentrations observed in most samples suggest that the phosphorus release in the Cambrian strata occurs beyond the zone of secondary mineral retention in the soil. These results have important implications for the eutrophication of inland surface waters in areas with bedrock phosphorus and anthropogenic acidity that is not neutralized before it contacts phosphatic rock.  相似文献   

不同增温方式下芦苇植硅体数量变化特征的对比分析     

刘洪妍  介冬梅  刘利丹  高卓  高桂在  石连旋  郭继勋  乔志和 《第四纪研究》2015,35(4)

由于未来全球变暖的情况仍可能持续,了解陆地生态系统对温度升高的响应对研究全球变化具有重要的参考价值.本文利用开顶式气室(Open Top Chamber,简称OTC)和红外线辐射器(Infrared Radiator,简称IR)对位于松嫩草原西南部吉林省长岭县腰井子村种马场境内的芦苇(Phragmites communis)群落进行模拟温度升高处理,研究增温对芦苇植硅体数量的影响.OTC增温方式设置两种不同的规格,分别用OTC-Ⅰ和OTC-Ⅱ表示,即本文利用OTC-Ⅰ、OTC-Ⅱ和IR这3种不同的增温方式来模拟温度升高,每种增温方式均设置了3个不同温度梯度的增温处理和1个对照处理,以期更详细的研究芦苇中植硅体数量与温度因子之间的动态关系.实验发现,3种不同增温方式对芦苇鞍型植硅体和芦苇硅化气孔的影响一致,即增温后芦苇鞍型植硅体的数量增加、芦苇硅化气孔的数量有所减少;在3种不同增温方式的影响下,芦苇尖型植硅体对增温的响应存在差异,在OTC(OTC-Ⅰ、OTC-Ⅱ)增温方式下,增温后芦苇尖型植硅体的数量减少,但在IR增温方式下,增温后芦苇尖型植硅体的数量增加.通过对比不同增温方式下芦苇植硅体数量变化特征的异同,有利于得出比较全面和令人信服的结论,同时为今后广大学者根据实际情况选择适宜的增温装置提供参考.  相似文献   

基于空气污染指数的太阳日总辐射计算方法   总被引：2，自引：1，他引：1       下载免费PDF全文

喻丽  申双和  陶苏林  李萌  丁从慧 《应用气象学报》2015,26(3):291-299

通过对2001—2012年全国23个站实测资料的分析,利用非线性回归法建立了以气温日较差、天文日照百分率和空气污染指数为主导因子的太阳日总辐射模型,这里简称为DSRM-Y模型 (Daily Solar Radiation Model-Y),检验其效果并与已有的DSRM-C模型 (Daily Solar Radiation Model-C) 进行效果比对。结果表明:太阳日总辐射与空气污染指数呈显著负相关,DSRM-Y模型的太阳日总辐射估算值与实测值的散点图以及平均偏差、均方根误差、误差分析均表现出较好的拟合效果。将模型应用于西宁、上海、昆明3个代表站,空气污染指数上升后,3个站太阳日总辐射均呈减少趋势;23个站DSRM-Y模型的均方根误差均小于DSRM-C模型,即DSRM-Y模型的拟合效果好于DSRM-C模型。  相似文献   

基于模糊综合评判法的辽宁省老旧砌体房屋震害预测     

臧石磊  冯石  李玉森  李东春 《地震研究》2019,(2):166-171,I0002

对辽宁省老旧砌体房屋现状及抗震能力进行分析,基于模糊综合评价法计算分析得到地震易损性矩阵,根据辽宁省地震震害实例对预测结果进行了验证和分析。结果表明:①辽宁省农村民居中的砌体结构总数量占房屋总数量比例超过95%,2000年以前所建房屋总数量占比76%。②由预测结果可知,辽宁省老旧砌体房屋在Ⅵ,Ⅶ,Ⅷ,Ⅸ度烈度下产生严重及以上破坏等级的房屋数量占比分别为6.5%,17.0%,53.5%,65.9%。③震害实例验证结果表明预测结果与实际震害结果之间差异性较小。  相似文献   

张北地区农村房屋抗震性能分析     

刘龙  刘志辉  刘晓丹  刘贾贾  马旭东  张展伟 《华北地震科学》2019,37(2):82-88

为厘清张北地区农村房屋抗震性能现状,对受张北地震影响最为严重的张北和尚义2县的农村房屋进行抽样调查,结合已有农村房屋震害经验,利用综合分析方法,建立该地区农村房屋抗震性能指数,并对其抗震性能进行定量分析。结果显示,该地区农村现有房屋以砖木结构和土木结构为主,抗震性能普遍较差;针对该地区农村房屋现状,给出改进其抗震性能的建议,对该地区地震风险管理具有一定的借鉴意义。  相似文献