首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 23 毫秒
1.
Human contribution to the European heatwave of 2003   总被引:4,自引:0,他引:4  
Stott PA  Stone DA  Allen MR 《Nature》2004,432(7017):610-614
The summer of 2003 was probably the hottest in Europe since at latest ad 1500, and unusually large numbers of heat-related deaths were reported in France, Germany and Italy. It is an ill-posed question whether the 2003 heatwave was caused, in a simple deterministic sense, by a modification of the external influences on climate--for example, increasing concentrations of greenhouse gases in the atmosphere--because almost any such weather event might have occurred by chance in an unmodified climate. However, it is possible to estimate by how much human activities may have increased the risk of the occurrence of such a heatwave. Here we use this conceptual framework to estimate the contribution of human-induced increases in atmospheric concentrations of greenhouse gases and other pollutants to the risk of the occurrence of unusually high mean summer temperatures throughout a large region of continental Europe. Using a threshold for mean summer temperature that was exceeded in 2003, but in no other year since the start of the instrumental record in 1851, we estimate it is very likely (confidence level >90%) that human influence has at least doubled the risk of a heatwave exceeding this threshold magnitude.  相似文献   

2.
The role of increasing temperature variability in European summer heatwaves   总被引:18,自引:0,他引:18  
Instrumental observations and reconstructions of global and hemispheric temperature evolution reveal a pronounced warming during the past approximately 150 years. One expression of this warming is the observed increase in the occurrence of heatwaves. Conceptually this increase is understood as a shift of the statistical distribution towards warmer temperatures, while changes in the width of the distribution are often considered small. Here we show that this framework fails to explain the record-breaking central European summer temperatures in 2003, although it is consistent with observations from previous years. We find that an event like that of summer 2003 is statistically extremely unlikely, even when the observed warming is taken into account. We propose that a regime with an increased variability of temperatures (in addition to increases in mean temperature) may be able to account for summer 2003. To test this proposal, we simulate possible future European climate with a regional climate model in a scenario with increased atmospheric greenhouse-gas concentrations, and find that temperature variability increases by up to 100%, with maximum changes in central and eastern Europe.  相似文献   

3.
A kind of temperature-sensitive nanotube array membrane was developed by modifying gold-nanotube array membranes with poly(N-isopropylacrylamide) (PNIPAm). The permeation ability of the mem-branes at different temperatures was investigated using sodium fluorescein and quantum dots as probes. The results showed that the pore diameter of nanotube was changed due to the reversible response of PNIPAm-modified membranes to temperature, and then the permeation ability of the mem-branes was changed. The permeation of fluorescence probes was slow and even almost blocked at 25℃ (below the lower critical solution temperature, LCST), since PNIPAm formed expanded structures and decreased the pore size. While at 40℃ (above the LCST), the permeation was increased, since PNIPAm became compact structures and the pore diameter was increased. Furthermore, the permeation ability of the temperature-sensitive nanotube array membranes could be adjusted reversibly and it is possible to use the membranes in nanofluidic devices, nanogates, etc.  相似文献   

4.
为了解中国北纬40°上空过渡流区大气月平均状态,使用热层-电离层-中间层大气能量与动力/宽频辐射计大气探测卫星资料,选取北京和酒泉上空50~110km高度2003-2014年共计12a的温度和密度数据,采用Lomb-Scargle谱分析方法分析了两站资料的周期特征、温度和密度周期随大气高度的变化特征,以及太阳活动对过渡流区的影响。结果表明:过渡流区的大气状态随经度变化很小,大气温度随时间变化呈现显著的4个月震荡和年震荡,自然年内温度的4个月震荡在过渡流区底层和顶层具有同位相特征,在中层为反位相特征;大气密度随时间存在半年变化和年变化特征,90km以下以年变化为主,90km以上年变化和半年变化同时存在;过渡流区上层温度和密度受到太阳活动的影响显著,强弱随月份变化。  相似文献   

5.
作者采用城镇化与经济协调发展理论和协调度的概念,建立城镇化水平与经济发展综合水平评价的指标体系以及二者的协调度模型,研究1993年南充建市以来城镇化与经济发展的协调度.研究结果表明,1993年以来南充城镇化与经济发展大致经历了三个阶段:2003年以前为失调和不协调阶段,2004年为弱协调阶段,2005年后进入协调时期.根据南充城镇化与经济发展的特点,提出了几点保持其城镇化与经济协调发展的建议.  相似文献   

6.
Methane is an important greenhouse gas, and its atmospheric concentration has nearly tripled since pre-industrial times. The growth rate of atmospheric methane is determined by the balance between surface emissions and photochemical destruction by the hydroxyl radical, the major atmospheric oxidant. Remarkably, this growth rate has decreased markedly since the early 1990s, and the level of methane has remained relatively constant since 1999, leading to a downward revision of its projected influence on global temperatures. Large fluctuations in the growth rate of atmospheric methane are also observed from one year to the next, but their causes remain uncertain. Here we quantify the processes that controlled variations in methane emissions between 1984 and 2003 using an inversion model of atmospheric transport and chemistry. Our results indicate that wetland emissions dominated the inter-annual variability of methane sources, whereas fire emissions played a smaller role, except during the 1997-1998 El Ni?o event. These top-down estimates of changes in wetland and fire emissions are in good agreement with independent estimates based on remote sensing information and biogeochemical models. On longer timescales, our results show that the decrease in atmospheric methane growth during the 1990s was caused by a decline in anthropogenic emissions. Since 1999, however, they indicate that anthropogenic emissions of methane have risen again. The effect of this increase on the growth rate of atmospheric methane has been masked by a coincident decrease in wetland emissions, but atmospheric methane levels may increase in the near future if wetland emissions return to their mean 1990s levels.  相似文献   

7.
本国生态足迹指标的构建及其实证研究   总被引:12,自引:1,他引:12  
基于生态足迹方法,提出并构建了度量国家环境压力总量的本国生态足迹指标,应用该指标对我国1961年~2003年的本国生态足迹、环境承载面积及本国生态赤字进行了计算,分析了中国环境压力的历史轨迹、发展趋势及其构成和主要矛盾,探讨了它们与经济发展的关系.结果表明我国的生态系统从20世纪70年代初就一直处于超载状态,本国生态足迹已达28亿多公顷.这表明我国经济的快速发展和工业化进程是以本国生态资源的大量消耗为基础的;而能源和农业问题是中国可持续发展需要解决的首要问题.  相似文献   

8.
对武汉纺织大学2003-2012年近10年发表的SCIE论文收录情况进行了研究,从年度、期刊及其影响因子以及学科类别三个方面进行了统计与分析,肯定学校近几年在这方面的进步和发展,同时也对学校提高发表科研论文被SClE收录提供了参考性建议。  相似文献   

9.
从1934年以来,湖南科技期刊入选CA数据库累计有21种,最早入选的科技期刊是《湖南地质勘探A辑》(Geol.Survey Hunan,Mere.Ser.A),1934年入选CA数据库;入选最晚的是《湖南理工学院学报(自然科学版)》(ISSN 1672-5298),2003年入选CA数据库。累计收录量最多的期刊是《中南工业大学学报》,中英文版从1981年以来累计被CA数据库收录了1900余条。2003年度有收录记载的13种科技期刊,全部是湖南高校学报,年度收录量最多的期刊依然是《中南工业大学学报》。  相似文献   

10.
2003年以来,成都市以"三个集中"为核心,以市场化为动力,以规范化服务型政府建设和基层民主政治建设为保障,在统筹城乡经济社会发展、推进城乡一体化方面进行了积极的探索。成都市城乡统筹发展的实践探索给了中西部地区很多有益的启示。  相似文献   

11.
选取1991~2003年柳州市降水pH值、酸雨率,1995年~2003年柳州市年耗煤量,1996年~2003年柳州市降水主要离子SO2-4/NO3-的比值等数据,通过计算Spearman秩相关系数分析近年来柳州市的酸雨变化趋势.结果表明,柳州市从1996年开始针对酸雨污染采取的治理对策取得了一定成效,使酸雨污染得到了有效控制.但是,柳州市大气污染有向煤烟型与机动车尾气混合型过渡的趋势,柳州市要加强机动车尾气的治理工作.  相似文献   

12.
底泥疏浚前后长春南湖浮游生物群落变化研究   总被引:7,自引:1,他引:7  
底泥疏浚是水体内源污染治理的重要手段,通过疏浚期间和疏浚后对长春南湖浮游生物2 a(每年6个月)的跟踪监测,研究了底泥疏浚前后长春南湖浮游生物的种群变化,对比分析了底泥疏浚前后南湖浮游生物的种类组成、数量和生物量变化趋势.结果表明疏浚后浮游植物群落发生了演替,由疏浚前的绿藻-蓝藻-硅藻型演变为目前的绿藻-硅藻-蓝藻型.同疏浚前相比,疏浚后浮游藻类数量平均下降11%,枝角类和桡足类等大型浮游动物所占比例降低;疏浚后浮游动物数量上升,生物量下降,浮游动物存在小型化趋势.  相似文献   

13.
The zonal displacement of the western Pacific subtropical high remarkably influences the climate anomalies in China. In this paper, a new zonal index of the subtropical high is defined by modifying previous indices, and is used to investigate the relationship between the zonal displacement of the subtropical high and the dominant modes of 850-hPa circulations. It is found that the zonal displacement of the subtropical high is significantly correlated with the first two leading modes of circulations. In particular, the correlation coefficient between the index and the time series associated with the second mode is as high as 0.78 in 1958-2003 (46 years). Since the second mode is not associated with significant anomalies of sea surface temperatures, the above results imply the difficulty in seasonal forecasting of the zonal displacement of the subtropical high. In addition, the interannual variability in the zonal displacement of the subtropical high has been considerably enhanced since 1978, due to the effects of both dominant modes, especially the second mode. This is likely to account for the frequent occurrence of anomalous climate in China during the recent two decades.  相似文献   

14.
The zonal displacement of the western Pacific subtropical high remarkably influences the climate anomalies in China. In this paper, a new zonal index of the subtropical high is defined by modifying previous indices, and is used to investigate the relationship between the zonal displacement of the subtropical high and the dominant modes of 850-hPa circulations. It is found that the zonal displacement of the subtropical high is significantly correlated with the first two leading modes of circulations. In particular, the correlation coefficient between the index and the time series associated with the second mode is as high as 0.78 in 1958-2003 (46 years). Since the second mode is not associated with significant anomalies of sea surface temperatures, the above results imply the difficulty in seasonal forecasting of the zonal displacement for the subtropical high. In addition, the interannual variability in the zonal displacement of the subtropical high is considerably enhanced since 1978, due to the effects of both dominant modes, especially the second mode. This is likely to account for the frequent occurrence of anomalous climate in China during the recent two decades.  相似文献   

15.
城市化与经济发展之间是一种相互促进、互为因果的关系。以往的研究多以经济发展水平为自变量来研究相应的城市化水平,而以城市化水平为自变量反向研究他们的关系则不多,这种研究具有更积极的实际意义,模型也更为简单。从人口城市化和空间城市化两个方面,用统计数据的时间序列和空间序列进行相关分析和回归分析,结果表明:中国单位人口城市化率增量对应的人均产值增量在350~1 600元/人之间,且新世纪以来逐年提高,中国人口城市化的经济效益越来越好;单位空间城市化率增量对应的地均产值增量在2.7~12.5万元/KM2之间,新世纪以来先降后升,存在波动,2003年后城市土地利用的经济效益逐年提高。  相似文献   

16.
以Delphi5.0为软件开发工具,设计梧州市人民医院管理信息系统。系统设计病人信息主线和成本核算主线来集成各个局部系统,包括有门诊和急诊管理、住院管理、医生工作站、药库管理、医疗统计报表管理、财务核算管理等13个功能模块。该管理信息系统已于2003年3月投入运行,运行效果良好,成功地实现了梧州市人民医院的信息化管理,提高了医院的经济管理水平和医疗服务质量。  相似文献   

17.
以“地名 学院”的综合性学院是我国高等教育的一支生力军。从2003年开始,连续两年的国家级精品课程建设,综合性学院课程门数尚未实现零突破。综合性学院应围绕人才培养目标,确定精品课程建设定位,以教育信息化推动精品课程建设,把教育的信息化作为提高教育质量的新手段。同时以精品课程建设为龙头,促进综合性学院教育信息化。  相似文献   

18.
基于改革开放后的河南铁路货物周转量时间序列数据,建立了退势模型。对其研究发现:存在1995年、1998年和2003年三个结构性断点,不同时期内波动特征差异较大。建立了分段线性模型,通过模拟和分析铁路货运量时间序列的历史波动和阶段性增长趋势,发现2003年至今的增速明显高于历史平均水平,并据此预测了未来的河南铁路运量。  相似文献   

19.
Wentz FJ  Schabel M 《Nature》2000,403(6768):414-416
Observations from Earth-orbiting satellites have been a key component in monitoring climate change for the past two decades. This has become possible with the availability of air temperatures from the Microwave Sounding Unit (MSU) since 1979, sea surface temperatures from the Advanced Very High Resolution Radiometer (AVHRR) since 1982 and, most recently, measurements of atmospheric water vapour content from the Special Sensor Microwave Imager (SSM/I) since 1987. Here we present a detailed comparison of each pair of these three time series, focusing on both interannual and decadal variations in climate. We find a strong association between sea surface temperature, lower-tropospheric air temperature and total column water-vapour content over large oceanic regions on both time scales. This lends observational support to the idea of a constant relative humidity model having a moist adiabatic lapse rate. On the decadal timescale, the combination of data sets shows a consistent warming and moistening trend of the marine atmosphere for 1987-1998.  相似文献   

20.
利用土地调查和统计资料分析了天津市自1949年以来耕地数量动态变化过程、驱动因子及其影响机制,并在此基础上,提出了抑制耕地流失和促进耕地增加的相关对策.1949年以来,天津市耕地数量动态变化经历了波动变化和持续缓慢减少两大阶段,耕地数量总体上缓慢减少.经济发展、人口增长、相关政策、环境变化和自然灾害等因素,对耕地数量变动的驱动作用非常明显.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号