中原地区气温的长期变化趋势研究

利用1957—2003年中原地区49个测站1、4、7、10月份日气温资料,对中原地区不同季节的气温变化特征进行了研究。结果表明:①中原地区极端最高气温、平均最高气温、平均气温、平均最低气温和极端最低气温与各站的气温指标具有显著的相关性,除个别台站的个别要素外,大都能通过信度为0.001的显著性检验;②除极端最低气温外,其余4个指标一致表明年际变化中冬季最大,秋季次之,夏季最小;③在全球气候变暖的背景下,中原地区近年来冬、春、秋季和年的气温指标基本呈增大趋势,其中年极端最低气温的上升最为剧烈,为0.550℃/10 a,而年极端最高气温的下降也比较明显,为0.395℃/10 a。除此之外,年极端最高气温和10月份的极端最低气温也有下降的趋势,7月份的气温指标整体表现为下降趋势,极端最低和平均最高气温可以通过信度为0.1的显著性检验。     

安康气象站1953-2016年气温变化特征研究

探讨气温变化规律,能够为发展农业生产、合理利用气候资源提供指导。根据安康气象站1953-2016年逐月气温数据,利用滑动平均、Mann-Kendall突变检验和Morlet小波分析等方法,对安康地区近64年气温变化特征进行了分析。结果显示：安康地区近64年除夏季气温和年极端最高气温呈微弱下降趋势以外,年均气温、春季气温、秋季气温、冬季气温、年极端最低气温均呈上升趋势,其中春季和冬季上升幅度最大,其变率分别0.156 ℃/10 a、0.169℃/10 a。安康地区近64年年均气温存在23和31 a两类变化周期,极端最高气温存在31 a变化周期,极端最低气温存在6、13、30 a三类变化周期。     

时间序列模型分析威海市近 50 年气温变化特征

利用时间序列模型,以及趋势分析、小波变换、M-K突变检验等统计学分析方法,分析了威海站1964年-2013年的平均气温、平均最高气温和平均最低气温的年变化、年平均气温的季节变化、时频特点,并对平均气温变化进行了突变检验,发现1964年-2013年威海市年平均气温呈上升趋势,气温倾向率为0.35℃/(10a);各季节气温倾向率分别为0.427℃/(10a)、0.268℃/(10a)、0.241℃/(10a)和0.287℃/(10a),其中春季(0.427℃/(10a))增温对该市年平均气温变化的贡献最大;春季气温呈现降-升-降-升-降的交替变化,为四季气温变化最明显的季节;年平均气温突变发生在1987年;各个季节在发生突变后均升温趋势显著。     

赣南地区近58年来极端气候变化趋势分析

极端天气事件对人类和自然环境的影响巨大,为评估其变化趋势,采用Mann-Kendall趋势检验和线性倾向估计法分析了赣南地区1956—2013年基于气温和极端降水的8个指标的变化趋势。结果表明:①年降雨总量没有显著变化,季节性变化差异较大;②气温在年尺度和季节尺度变化一致,几乎全部站点年最高气温和年最低气温都有显著上升趋势,且秋季上升幅度最大,其最低气温最大上升幅度为每10 a上升0.39 ℃;除春季外,日温差均为减小趋势;③极端降水事件有增加趋势,年尺度上最大日降雨量和最大3日降雨量均有显著增加趋势,冬季增加趋势更加显著。本研究结果显示赣南地区气温变化趋势与全球变暖保持一致,极端降水事件也在加剧。     

艾比湖流域气温变化基本特征分析

利用艾比湖流域近40a来气温资料,分析了气温的变化特征。结果表明:艾比湖流域气温有着明显上升的总趋势,尤其以20世纪90年代最为明显;艾比湖流域的气温升高具有明显的季节性差异,表现为冬季变暖明显,而春季变暖的趋势较为缓慢。新疆近40a气温同样呈上升趋势,而且变暖主要在冬季,艾比湖流域年气温的演变特点与新疆的基本一致。艾比湖流域最高和最低气温的变化普遍存在不对称性。即最低气温明显上升,而最高气温上升不明显或呈下降趋势,并导致气温日较差显著减小。此种现象尤以夏、秋、冬3季表现最为明显。     

1960年-2012年长三角地区极端气温时空变化特征

利用1960年-2012年长三角地区34个气象站逐日气温资料,采用趋势分析、小波分析、Mann-Kendall检验、样条插值等方法,分析了长三角地区的极端气温时空变化特征。结果表明:近53年,冷指数均呈显著上升趋势,且均通过了0.01的信度检验,气候倾向率分别达-2.8d/(10a)、-4.1d/(10a)和0.45℃/(10a),暖指数虽也有上升趋势但趋势较为不显著,仅有暖昼指数与极端最高气温通过了0.05的信度检验。空间分布上,高温日数和极端最高气温呈北低南高、东低西高、沿海低内陆高的分布规律,低温日数和极端最低气温与之相反。变化趋势上,极端气温指数基本均表现为上升趋势,其中极端低温和极端高温上升趋势最明显的地区为上海、南京、杭州等大城市及其周边区域。     

河南省近50年气候变化分析

选取河南省气象站1961-2010年共50年的平均气温、极端最高气温、极端最低气温、平均最高气温、平均最低气温、无霜期、降水量、蒸发量等9种观测资料,对河南省和8个分区的气候变化的情况进行了分析。由分析可以看出,河南省年平均气温总体呈明显上升趋势,极端最高气温总体呈下降趋势,极端最低气温总体呈上升趋势,无霜期总体呈延长趋势,年降水量总体略呈上升趋势,年蒸发量总体呈明显下降趋势。8个分区和河南省变换趋势接近,但也略有不同。     

博尔塔拉河河源气温与径流量变化趋势研究

根据博尔塔拉河河源(温泉水文站)1960-2012年的平均气温和径流量资料,应用线性倾向估计法和Mann-kendall方法对平均气温和径流量趋势进行了检验分析。结果表明,根据线性倾向估计法分析,1960-2012年博尔塔拉河河源平均气温除夏季外均呈上升趋势,秋、冬季和全年上升明显;春、夏、秋季和全年的径流量均呈上升趋势,秋、冬季和全年变化明显,秋季和全年呈上升趋势,冬季呈下降趋势。平均气温和径流量年内变化呈两头小、中间大的分布,季节分布明显。Mann-Kendall趋势检验表明,博尔塔拉河河源秋、冬季和全年平均气温变化呈明显上升趋势;秋、冬季和全年径流量变化明显,秋季和全年呈明显上升趋势,冬季呈明显下降趋势。     

梧州站1959—2005年径流变化对气候变化的季节响应

为研究西江流域中游的径流变化对气候变化的季节性响应,探寻径流变化的季节性特征,为西江流域中游的防汛减灾工作提供决策参考及建议。通过距平法、斯皮尔曼秩次相关检验法、R/S分析法,分析梧州站的径流变化及气候变化特征,得出西江流域中游梧州站冬、春、夏气温均有上升趋势,冬季的增幅高于春季和夏季,平均气温增幅达到了0.31℃/10a;西江流域中游冬季和夏季的平均日最低气温增加幅度较大,且增加趋势均为极显著,但四季的降水量变化并不平稳。其中,四季年降水量除冬季外都有减少的趋势,趋势大多不显著。同时,西江流域梧州站冬、春、夏径流总量都有增加趋势,秋季径流总量则呈现下降趋势。气温与径流量呈负相关,降水与径流量呈显著性正相关。     

蚂蚁森林种植地鄂尔多斯市1959-2018年气温及降水变化特征研究

基于鄂尔多斯市3个气象站点1959-2018年逐月降水及气温数据,使用M-K检验法、滑动平均、Morlet小波分析法、线性回归及R/S分析法,对蚂蚁森林种植地鄂尔多斯市1959-2018年气温及降水特征进行分析。结果表明:近60年鄂尔多斯市年平均气温、年降水量和年极端气温呈上升趋势,气候正向暖湿化发展; 1993、1970、1987和1961年分别为年平均气温和年极端最高、最低气温以及年降水量的突变时间;年极端最低、最高气温和年降水量以及年平均气温的共振周期为28 a;在鄂尔多斯市未来气候变化特征分析的Hurst指数中,年降水量小于0. 5,年极端最低气温、最高气温和年平均气温均高于0. 5,表明气温在未来一段时期还会呈上升趋势,降水则呈下降趋势。     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.