广州市室内地温的变化规律分析     

林芳妮  张东  方一川  郭春迓  涂静 《广东气象》2014,36(5):14-18

对2012年2月—2014年2月间广州室内地温进行了分析,同时还分析了其与室外气温的相互关系,结果表明：室内日平均地温随月份的变化呈正弦曲线变化,并且其变化与室外平均气温的变化有很高的相关性,但室内地温的升降幅小于室外气温的升降幅,春夏季室外气温高于室内地温,而秋冬季节相反;室内地温的日较差通常很小,一般小于1℃;当室内地温日较差在1～2℃时,多是室外处于持续的升温或持续降温状态;当室内地温日较差大于2℃时,多是因受冷空气影响。有冷（暖）空气影响时,室内地温下降（上升）较室外气温有一定程度的滞后,室内地温下降（上升）幅度较小但保持一致下降（上升）趋势,二者日平均温度变化趋势较为一致。  相似文献   

集合数值预报在洪水预报中的应用进展   总被引：6，自引：2，他引：4       下载免费PDF全文

赵琳娜  刘莹  党皓飞  姜迪  段青云  王彬雁  白雪梅  梁莉 《应用气象学报》2014,25(6):641-653

水文集合预报是近几年正在形成和发展的水文预报分支,其发展大致可分为两个阶段:第1阶段是1970年至20世纪末进行的长期径流预报,第2阶段从21世纪开始,主要学习气象数值预报中集合预报的概念在短期水文集合预报中的应用。目前,除了单一预报中心的集合预报系统在水文集合预报中应用外,多个预报中心的集合预报大集合也逐渐被应用于流域水文预报,甚至一些小流域的洪水预报。如利用TIGGE(THORPEX Interactive Grand Global Ensemble)集合预报驱动形成的大气-水文-水力的串联系统进行早期的洪水预警研究,将全球集合预报作为洪水模型输入的有限区域模式的初始条件和侧边界条件的研究。这些均表明,基于水文集合预报的洪水预报增加了预报附加值,并能够延长预警提前时间。以欧洲中期天气预报中心的欧洲洪水预警系统(EFAS)和美国NOAA的先进水文预报系统(AHPS)为代表,实现了集合预报在洪水中的实时业务预报,但仍存在数据处理和计算量大,以及如何基于集合水文预报做决策等问题。对于水文集合预报的前处理和后处理的各种技术已处于探索和验证阶段,如何更好地理解基于概率预报的洪水预警决策仍存在许多困难和挑战。  相似文献   

Hydrothermal Sedimentary Mineralization of the Super‐large Bamianshan Fluorite Deposit in Zhejiang Province,China     

HAN Yuchuan  XIA Xuehui  PANG Siyu  XU Shaokang 《《地质学报》英文版》2012,86(3):762-768

The Bamianshan fluorite deposit is a super-large one recently discovered in Zhejiang Province of China. This paper presents an analysis of its geological background, orebody and ore characteristics, petrochemical characteristics of host rocks, rare earth elements (REE) of rocks and ores, fluid inclusions in fluorite and Sm-Nd isotopic features in an effort to study its sedimentary mineralization. The result shows that the super-large Bamianshan fluorite deposit is of hydrothermal sedimentation genesis, deformed by the later hydrothermal fluid. Integrated with host rocks and orebody characteristics, it is inferred that the deposit originates from the Cambrian sedimentary rocks. And the later magmatic activities deformed some orebodies in different degrees, forming steeply dipping vein orebodies in the tectonic belts regionally.  相似文献   

Multivariate analysis of trace elements in shallow groundwater in Fuchu in western Tokyo Metropolis,Japan     

Dang Quoc Thuyet  Hirotaka Saito  Takeshi Saito  Shigeoki Moritani  Yuji Kohgo  Toshiko Komatsu 《Environmental Earth Sciences》2016,75(7):559

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Predictive uncertainty of peak outflow relations for landslides dam breach     

Chao Dang  Nana Chu  Yu Ding 《Environmental Earth Sciences》2014,72(11):4265-4271

Risk assessment development considering the failure of landslide dams often requires the estimation of peak outflow through the breach. The empirical equations based on data from case studies tend to be the first direct approach. This paper conducted an uncertainty analysis when these empirical relations were utilized to predict the peak outflow of a breached landslide dam. The results suggest that the relations derived from manmade dams or embankments typically overestimate the peak outflow about 1/5 to 3/4 of an order of magnitude; and the relations derived from the database of landslide dams have much smaller mean prediction errors and also exhibit broad uncertainty bands. Application of the uncertainly analysis was illustrated by the Tangjiashan landslide dammed lake, formed during 2008 Wenchuan earthquake. In addition, the predicted results from Eq. 1 deduced herein were considered to be the reliable estimate of peak outflow through the breach of landslide dam.  相似文献   

Mechanical Behavior of Light-Weight Soil Under Consolidated Drained Shear Condition     

Tian-Shun Hou  Wei Wang  Ya-Sheng Luo  Jin-Qian Dang  Xiu-Juan Yang 《Marine Georesources & Geotechnology》2013,31(3):264-276

To reveal the influence of material composition on mechanical properties of light-weight soil, stress-strain -volumetric strain characteristics and Poisson's ratio of mixed soil were researched by consolidated drained shear tests. The results show that light-weight soil is a kind of structural soil, so its mechanical properties are affected by mixed ratio and confining pressure, and mixed soil possesses structural yield stress. When confining pressure is less than the structural yield stress, strain softening occurs; when confining pressure is more than the structural yield stress, strain hardening is observed. There are two kinds of volume change behavior: shear contraction and shear dilatancy. Shear dilatancy usually leads to strain softening, but there isn't an assured causal relationship between them. Poisson's ratio of mixed soil is a variational state parameter with the change of stress state, it decreases with increased confining pressure, and it increases with increased stress level. When axial strain is near 5%, Poisson’ ratio is gradually close to a steady value. The main range of Poisson's ratio is 0.25～0.50 when confining pressure changes from 50 to 300 kPa. When unconfined compressive strength of mixed soil is less than 328 kPa, its stress-strain-volumetric strain characteristics can be predicted very well by Duncan-Chang model (E-B model). However, when the range of unconfined compressive strength is [328 kPa, 566 kPa], the model can't predict stress-strain characteristics accurately when confining pressure is under 200 kPa, and it also can't predict the strong shear dilatancy phenomenon of mixed soil under low confining pressure.  相似文献   

    

Xu Hui  Zhang Weiping  Lang Xuxing  Guo Xia  Ge Wenzhong  Dang Renqing  Takao Takeda 《大气科学进展》2000,17(3):403-412

During the Meiyu period in June and July of 1998, intensified field observations have been carried out for the project “Huaihe River Basin Energy and Water Cycle Experiment (HUBEX)”. For studying Meiyu front and its precipitation in Huaihe River basin, the present paper has performed analysis on the middle and lower level wind fields in the troposphere by using the radar data obtained from the two Doppler radars located at Fengtai district and Shouxian County. From June 29 to July 3 in 1998, the continuous heavy precipitation occurred in Huaihe River basin around Meiyu front. The precipitation process on July 2 occurred within the observation range of the two Doppler radar in Fengtai district and Shouxian County. The maximum rainfall of the Meiyu front was over 100 mm in 24 h, so it can be regarded as a typical mesoscale heavy precipitation process related to Meiyu front. Based on the wind field retrieved from the dual Doppler radar, we find that there are meso-γ scale vertical circulations in the vertical cross-section perpendicular to Meiyu front, the strong upward motion of which corresponds to the position of the heavy rainfall area. Furthermore, other results obtained by this study are identical with the results by analyzing the conventional synoptic data years ago. For example: in the vicinity of 3 km level height ahead of Meiyu front there exists a southwest low-level jet; the rainstorm caused by Meiyu front mainly occurs at the left side of the southwest low-level jet; and the Meiyu front causes the intensification of the low-level convergence in front of it. This research was supported by Project HUBEX (Project Number: 49794030) which is funded by the National Natural Science Foundation of China (NSFC).  相似文献   

Open-coast intertidal deposits and the preservation potential of individual laminae: a case study from east-central China   总被引：3，自引：0，他引：3  

Congxian Li  Ping Wang  Fan Daidu  Dang Bing  & Li Tiesong 《Sedimentology》2000,47(5):1039-1051

Monitoring of sedimentation and erosion was conducted on an open coastal tidal flat on the southern flank of the Yangtze delta. Various elevation references were established in the intertidal zone and monitored intensively for 4 months in order to examine fortnightly and seasonal (calm weather and storm season) sedimentation and erosion. Longer term (100 years) sedimentation and preservation were investigated through examination of cores and trenches. Two different vertical grouping patterns of tidal bedding were distinguished with thinner and thicker sandy laminae. The number of sand-dominated layers and individual muddy and sandy lamina in the cores were compared with theoretically derived sedimentation rates in order to assess long-term preservation potential. Waves, especially high storm waves, have a significant influence on sedimentation and the preservation of intertidal deposits along the open-coast tidal flat. Monitoring during one season indicated that the sand-dominated layer was directly related to storm deposits, while the mud-dominated layer was deposited during calm weather conditions. The variation in sandy lamina thickness was not related to spring–neap tidal cycles during the monitoring period. The assumption of 100% preservation of sandy laminae deposited during every tidal cycle, which has been assumed in previous time-series analyses for the identification of palaeotidal periodicity, was found to be unrealistic along this open-coast tidal flat. Preservation potential decreases as temporal scale increases. During one neap–spring tidal cycle, the preservation potential of individual sandy and muddy laminae was of the order of 10%. Over a period of 100 years, the estimated preservation potential of individual laminae, including both calm weather and storm deposits, decreased to 0·2%. The 100-year preservation potential of storm-induced, sand-dominated layers was estimated to be of the order of 10%.  相似文献   

The Mineralization of the Beiya Skarn Gold Deposit in Yunnan, Southwest China     

HE Wenyan  YU Xuehui  DONG Guochen  HUANG Xiongfei 《《地质学报》英文版》2013,87(Z1):692-693

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江西大游山地区水系沉积物地球化学特征及找矿方向          下载免费PDF全文

蒋起保  魏锦  欧阳永棚  饶建锋  李艳萍  张雪辉 《沉积与特提斯地质》2021,41(1):73-81

朱溪特大型钨铜矿床的发现,使大游山地区W-Cu多金属的成矿潜力受到广泛的关注.本文依据1:5万水系沉积物测量成果,探讨大游山地区成矿元素含量、分布、组合以及综合异常等特征.结果显示,朱溪地区与长源坞地区异常强度高,规模大,元素套合好,朱溪地区为W-Cu多金属找矿远景区,长源坞地区为W-Bi多金属找矿远景区.  相似文献