Climatic characteristics of high temperature in East China during 1961–2005     

SHI Jun  TANG Xu  CUI Linli 《地理学报》2008,18(3):283-294

Based on the daily maximum temperature data covering the period 1961–2005, temporal and spatial characteristics and their changing in mean annual and monthly high temperature days (HTDs) and the mean daily maximum temperature (MDMT) during annual and monthly HTDs in East China were studied. The results show that the mean annual HTDs were 15.1 and the MDMT during annual HTDs was 36.3℃ in the past 45 years. Both the mean annual HTDs and the MDMT during annual HTDs were negative anomaly in the1980s and positive anomaly in the other periods of time, oscillating with a cycle of about 12–15 years. The mean annual HTDs were more in the southern part, but less in the northern part of East China. The MDMT during annual HTDs was higher in Zhejiang, Anhui and Jiangxi provinces in the central and western parts of East China. The high temperature process (HTP) was more in the southwestern part, but less in northeastern part of East China. Both the HTDs and the numbers of HTP were at most in July, and the MDMT during monthly HTDs was also the highest in July. In the first 5 years of the 21st century, the mean annual HTDs and the MDMT during annual HTDs increased at most of the stations, both the mean monthly HTDs and the MDMT during monthly HTDs were positive anomalies from April to October, the number of each type of HTP generally was at most and the MDMT in each type of HTP was also the highest.  相似文献   

Foreword     

George W. Housner 《地震工程与工程振动(英文版)》2008,7(1):I0002-I0002

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings have caused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence of earthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structures during earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant, and finally, how to cope with earthquake damage and restore a city to normal functioning.  相似文献   

超大型"管幕-箱涵"顶进施工土体变形的分析与预测   总被引：1，自引：0，他引：1  

孙钧  虞兴福  孙旻  李向阳 《岩土力学》2006,27(7):1021-1027

结合上海市中环线北虹路下立交地道工程采用“管幕-箱涵”顶进的非开挖施工全过程,分别应用ANSYS和FLAC三维数值分析程序,对顶进施工所引起的地表变形位移进行了全过程的动态仿真模拟,并采用弹性地基梁法和室内模拟试验以及现场实测数据比拟法,对地表变形特征进行了系统地研究,最后应用软科学的智能方法,对“管幕-箱涵”顶进非开挖工法所引起的地表变形位移进行了人工神经网络滚动预测.其研究成果已经提交施工部门参考和采用.  相似文献   

崩塌滑坡防治施工监测与治理效果   总被引：1，自引：0，他引：1  

夏永忠  易庆林 《中国地质灾害与防治学报》2006,17(1):4-8

论文较系统地介绍了崩塌滑坡地质灾害防治施工安全监测和防治效果监测的目的和特点、监测方案布置原则,监测内容与监测方法等。指出防治施工安全监测和防治效果监测是整个监测过程的两个不同阶段。其监测方案布置应当统筹规划,区别对待。还以2个工程实例进行了阐述和分析,对开展崩塌滑坡防治阶段的监测工作有较强的实用价值。最后,作者强调监测工作应贯穿于防治工程的始终。  相似文献   

一次大气污染过程的降水天气特征及相关分析     

李红斌  傅瑜  张靖萱  何阳  濮文耀  夏葳  赵繁盛  周德平  张殿刚 《气象》2018,44(5):655-664

本文分析了大连市2015年11月16日一次污染过程的降水(降水量为5mm)天气特征及NCEP/NCAR再分析资料,结果表明,天气形势场为典型的大连秋、冬季的高空槽降水,而大气层结无论是在污染前期,还是污染后期的降水阶段均为稳定层结,有逆温层存在;空气上升运动于降水前持续了较长时间(近十几小时),表明近地面细颗粒物(PM_2.5)随着上升气流会源源不断输送到高空,其中部分颗粒物转化为云中冰核,补充了降雨云中冰核数;同时,对本次污染降水过程及大连近两年秋、冬季另外三次小雨(降水量5mm)降水过程的云中液态水含量、地面降水量和PM_2.5的小时观测值及其变化进行了详细讨论和分析发现,当PM_2.5浓度较低时,降雨云中的冰核数缺乏,地面降水较小,适合实施人工增雨(雪)作业,增加云中冰核及地面降水,当PM_2.5浓度较高,特别是出现大气污染时,降雨云中的冰核数会相对增加(甚至过量),地面降水较充分(或出现消减雨情况),此时人工影响作业应根据实际情况减小作业剂量,或减少作业。此外,相关综合分析表明,大连市大气污染源有两种,一为本地源,二为外来源;一定程度的降水对本地源大气污染能起到沉降作用,对外来源不明显。  相似文献   

一种应急测绘保障模式的探讨     

肖兰玲  顾钰培  徐国庆 《测绘与空间地理信息》2014,(12)

各种自然灾害的发生,给国家和人民的生命财产造成了巨大的损失,应急测绘保障作为应急救灾的一种有效支持手段,对应急救灾工作发挥着不可替代的作用,然而传统测绘作业模式难以满足应急救灾工作对时效性的要求,在多次应急测绘保障任务的基础上,探索出了一种有效的应急测绘保障模式,提高了应急测绘保障的时效性.  相似文献   

COMPARATIVE ANALYSIS OF THE INTENSIFYING AND WEAKENING LANDFALL TROPICAL CYCLONES DURING EXTRATROPICAL TRANSITION OVER CHINA   总被引：1，自引：1，他引：0  

李侃  徐海明 《热带气象学报(英文版)》2015,21(1):23-33

Based on the Tropical Cyclone(TC) Yearbooks data and JRA-25 reanalysis data from the Japan Meteorological Agency(JMA) during 1979-2008, dynamic composite analysis and computation of kinetic energy budget are used to study the intensifying and weakening TCs during Extratropical Transition over China. The TCI shows strong upper-level divergence, strengthened low-level convergence and significantly enhanced upward motion under the influence of strong upper-level troughs and high-level jets. The TCI is correspondingly intensified after Extratropical Transition(ET); TCW exhibits strong upper-level divergence, subdued low-level convergence and slightly enhanced upward motion under the influence of weak upper-level troughs and high-level jets. It then weakens after ET. The increase(decrease) of the generation of kinetic energy by divergence wind in TCI(TCW) at low level is one of the major reasons for TCI’s intensification(TCW’s weakening) after transformation. The generation of kinetic energy by divergence wind is closely related to the development of a low-level baroclinic frontal zone. The growth of the generation of kinetic energy by rotational wind in TCI at upper level is favorable for TCI’s maintenance, which is affected by strong upper-level troughs. The dissipation of the generation of kinetic energy by rotational wind in TCW at upper level is unfavorable for TCW’s maintenance, which is affected by weak upper-level troughs.  相似文献   

末次冰消期以来兰州地区冬季风变化研究   总被引：9，自引：0，他引：9  

陈发虎  吴海斌  张家武  江海斌 《第四纪研究》1999,19(4):306-313

研究发现,本次冰消期以来兰州地区大气风力发生了显著变化,全新世早中期大气风力最弱,随后大气风力回返到接近冰期的状况,约1300aB．P．开始大气风力再次减弱,现代是大气风力又一次增强时期;近地面风向有由西北向东北变化的趋势,是大气环流位置变化的结果。在总的变化背景下,大气风力具有约1500a的准周期。我们认为,间冰期季风中国的短尺度气候变化与冰期有差异,前者与低纬度地区联系更密切。  相似文献   

千米桥潜山凝析油气藏奥陶系碳酸盐岩储层特征及演化          下载免费PDF全文

武站国  梁锋  朗静 《地质找矿论丛》2006,21(4):288-293

千米桥潜山奥陶系储层经历了两次裸露岩溶及古近纪后的深埋藏成岩作用.其中印支-早燕山期裸露岩溶属溶丘(梁)洼地型岩溶发育模式,是储集空间形成的重要时期.6期胶结事件的详细解剖表明,喜马拉雅期深埋藏岩溶主要与腐蚀性热流体作用有关,是形成现今储层孔隙系统的最关键时期.局限的热液岩溶和裸露的背斜轴部之下的混合带对千米桥潜山奥陶系孔隙分布具有重要控制作用,预期在印支期挤压逆冲作用形成的背斜轴部,特别是潜山内幕背斜形态与潜山顶面形态相互协调的区域,应是储层发育最好的部位.  相似文献   

青藏高原地表温度对华北汛期降水变化的影响   总被引：11，自引：4，他引：7  

余锦华  荣艳淑  任健 《气象科学》2005,25(6):579-586

利用1980-2001年青藏高原月平均地表温度、1961～2001年我国160站月降水以及NECP／NCAR再分析月平均高度场资料,分析了华北地区汛期降水与青藏高原地表温度的关系,结果表明华北地区汛期降水与青藏高原5～6月地表温度具有显著的正相关。相关场的正值中心位于高原的东北部和西南部地区。华北地区汛期降水偏少年,青藏高原前期5～6月地温以负距平为主且距平值较小;相反,降水偏多年,青藏高原前期5～6月地温以正距平为主且距平值较大。EOF和SVD分析表明,青藏高原5～6月地温和华北地区汛期降水的第一典型场都表现出大体一致的变化特点。此外,诊断分析得到,青藏高原5～6月地温偏高年,7～8月西太平洋副热带高压的强度偏强,位置偏北;地温偏低年,西太平洋副热带高压的强度偏弱,位置偏南。  相似文献