皖南天井山金矿床地质-地球化学特征及找矿前景   总被引：7，自引：0，他引：7       下载免费PDF全文

杨晓勇  段留安  孙卫东  方世明  余良范  范增平 《地质学报》2011,85(6):965-978

皖南地区山高林密,地质工作条件差,基础地质工作相对还很薄弱,金矿的找寻工作一直没有取得大的突破.本文选取皖南休宁县天井山金矿为切入点,对该矿床地质、地球化学特征进行了分析,基本理清了本区与金成矿相关的各种因素,对矿床成因进行了剖析,并对其找矿前景作了探讨.系统统计分析区内地层、岩浆岩、矿石的主微量元素、稀土元素特征,讨...  相似文献   

东海内陆架EC2005孔沉积物粒度分形特征   总被引：1，自引：0，他引：1       下载免费PDF全文

徐方建  李安春  李铁刚  陈世悦  邱隆伟  操应长  林承焰 《地质学报》2011,85(6):1038-1044

对位于浙-闽沿岸泥质带的EC2005孔沉积物粒度分形特征以及与平均粒径和分选系数的关系进行了探讨.EC2005孔沉积物粒度在累积含量5%～95%的无标度区间内,统计自相似程度高,具有分形特征.沉积物平均粒径与分维值既存在正相关,也有负相关关系.二者正、负相关关系的分界点表现为平均粒径7.0φ左右,＜7.0φ时,平均粒径...  相似文献   

湖南台地泥盆纪末绝灭事件后的微生物沉积   总被引：1，自引：0，他引：1       下载免费PDF全文

侯鸿飞  周怀玲  刘建波 《地质学报》2011,85(1):145-156

湖南中南部浅水碳酸岩台地,泥盆系顶部假整合面之上,石炭纪海进最早期,相当四射珊瑚Cystophrentis-Uralinia间隔带和单房室有孔虫带的层位,普遍发育厚度不等(7~30m)的微生物沉积.宏观上为条带状或斑块、瘤状构造,大部分由核形石组成,局部发育凝块构造内碎屑.它们均属微生物成因,代表汉根卑尔格绝灭事件后(...  相似文献   

Improving the assessment of ICESat water altimetry accuracy accounting for autocorrelation     

Hani Abdallah  Jean-Stéphane Bailly  Nicolas Baghdadi  Nicolas Lemarquand 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(6):833-844

Given that water resources are scarce and are strained by competing demands, it has become crucial to develop and improve techniques to observe the temporal and spatial variations in the inland water volume. Due to the lack of data and the heterogeneity of water level stations, remote sensing, and especially altimetry from space, appear as complementary techniques for water level monitoring. In addition to spatial resolution and sampling rates in space or time, one of the most relevant criteria for satellite altimetry on inland water is the accuracy of the elevation data. Here, the accuracy of ICESat LIDAR altimetry product is assessed over the Great Lakes in North America. The accuracy assessment method used in this paper emphasizes on autocorrelation in high temporal frequency ICESat measurements. It also considers uncertainties resulting from both in situ lake level reference data. A probabilistic upscaling process was developed. This process is based on several successive ICESat shots averaged in a spatial transect accounting for autocorrelation between successive shots. The method also applies pre-processing of the ICESat data with saturation correction of ICESat waveforms, spatial filtering to avoid measurement disturbance from the land–water transition effects on waveform saturation and data selection to avoid trends in water elevations across space. Initially this paper analyzes 237 collected ICESat transects, consistent with the available hydrometric ground stations for four of the Great Lakes. By adapting a geostatistical framework, a high frequency autocorrelation between successive shot elevation values was observed and then modeled for 45% of the 237 transects. The modeled autocorrelation was therefore used to estimate water elevations at the transect scale and the resulting uncertainty for the 117 transects without trend. This uncertainty was 8 times greater than the usual computed uncertainty, when no temporal correlation is taken into account. This temporal correlation, corresponding to approximately 11 consecutive ICESat shots, could be linked to low transmitted ICESat GLAS energy and to poor weather conditions. Assuming Gaussian uncertainties for both reference data and ICESat data upscaled at the transect scale, we derived GLAS deviations statistics by averaging the results at station and lake scales. An overall bias of −4.6 cm (underestimation) and an overall standard deviation of 11.6 cm were computed for all lakes. Results demonstrated the relevance of taking autocorrelation into account in satellite data uncertainty assesment.  相似文献   

全国矿业权实地核查信息系统建设与应用     

谭永杰  李景朝  王永志  林燕 《测绘软科学研究》2011,(5):7-9

系统介绍了全国矿业权实地核查数据采集与信息系统歼发建设的工作背景、主要工作内容和总体框架,列述了取得的主要成果,并系统阐述了成果的应用及社会经济效益。  相似文献   

Multi-Model Projection of July–August Climate Extreme Changes over China under CO_2 Doubling. Part II: Temperature     

LI Hongmei  FENG Lei  ZHOU Tianjun 《大气科学进展》2011,28(2):448-463

This is the second part of the authors’ analysis on the output of 24 coupled climate models from the Twentieth-Century Climate in Coupled Models (20C3M) experiment and 1% per year CO 2 increase experiment (to doubling) (1pctto2x) of phase 3 of the Coupled Model Inter-comparison Project (CMIP3). The study focuses on the potential changes of July–August temperature extremes over China. The pattern correlation coefficients of the simulated temperature with the observations are 0.6–0.9, which are higher than the results for precipitation. However, most models have cold bias compared to observation, with a larger cold bias over western China (>5°C) than over eastern China (<2°C). The multi-model ensemble (MME) exhibits a significant increase of temperature under the 1pctto2x scenario. The amplitude of the MME warming shows a northwest–southeast decreasing gradient. The warming spread among the models (～1°C– 2°C) is less than MME warming (～2°C–4°C), indicating a relatively robust temperature change under CO 2 doubling. Further analysis of Geophysical Fluid Dynamics Laboratory coupled climate model version 2.1 (GFDL-CM2.1) simulations suggests that the warming pattern may be related to heat transport by summer monsoons. The contrast of cloud effects also has contributions. The different vertical structures of warming over northwestern China and southeastern China may be attributed to the different natures of vertical circulations. The deep, moist convection over southeastern China is an effective mechanism for "transporting" the warming upward, leading to more upper-level warming. In northwestern China, the warming is more surface-orientated, possibly due to the shallow, dry convection.  相似文献   

Features of the Extremely Severe Drought in the East of Southwest China and Anomalies of Atmospheric Circulation in Summer 2006   总被引：1，自引：0，他引：1       下载免费PDF全文

LI Yonghu  XU Haiming  LIU De 《Acta Meteorologica Sinica》2011,25(2):176-187

The spatial-temporal features of the extremely severe drought and the anomalous atmospheric circulation in summer 2006 are analyzed based on the NCEP/NCAR reanalysis data, the characteristic circulation indices given by the National Climate Center of China, and the daily precipitation data of 20 stations in the east of Southwest China (ESC) from 1959 to 2006. The results show that the rainless period started from early June and ended in early September 2006 with a total of more than 80 days, and the rainfall was especially scarce from around 25 July to 5 September 2006. Precipitation for each month was less than normal, and analysis of the precipitation indices shows that the summer precipitation in 2006 was the least since 1959. The extremely severe drought in the ESC in summer 2006 was closely related to the persistent anomalies of the atmospheric circulation in the same period, i.e., anomalies of mid-high latitude atmospheric circulation, western Pacific subtropical high (WPSH), westerlies, South Asian high, lower-level flow, water vapor transport, vertical motion, and so on. Droughts usually occur when the WPSH lies anomalously northward and westward, or anomalously weak and eastward. The extreme drought in summer 2006 was caused by the former. When the WPSH turned stronger and shifted to the north and west of its normal position, and the South Asian high was also strong and lay eastward, downdrafts prevailed over the ESC and suppressed the water vapor transfer toward this area. At the same time, the disposition of the westerlies and the mid-high latitude circulation disfavored the southward invasion of cold air, which jointly resulted in the extremely severe drought in the ESC in summer 2006. The weak heating over the Tibetan Plateau and vigorous convective activities over the Philippine area were likely responsible for the strong WPSH and its northwestward shift in summer 2006.  相似文献   

2009年中国东北夏季低温及其与前期海气系统变化的联系   总被引：6，自引：2，他引：4  

沈柏竹  刘实  廉毅  封国林  李尚锋  龚志强 《气象学报》2011,69(2):320-333

依据中国东北地区拥有百年地面观测记录的长春和哈尔滨测站气温资料、NCEP/NCAR再分析资料和英国哈得来中心海表温度资料,揭示2009年东北地区发生的迄今已有15年没有出现的夏季低温事件成因.结果表明:发生东北夏季低温时的水平和垂直环流结构均为低值系统,东北冷涡异常活动是其最直接的影响因子;有利的年代际变化背景是,哈尔滨和长春6-8月平均气温年代际尺度(≥9 a)的振荡值1999-2008年约-O.8℃/10 a,显著低于全球变暖东北区域响应的线性增暖值0.2℃/10 a(1961-2000年),与长春和哈尔滨夏季气温呈正相关的前一年冬季太平洋极涡面积指数年代际振荡亦呈显著下降趋势.与1994-2008年东北夏季高温的500 hPa平均环流距平场显著不同,北极涛动呈强的负位相分布,东北亚、阿留申和北大西洋上空为显著负距平区;2009年前一年冬季与明显低温的1972年的前一年冬季北太平洋涛动均呈显著的负位相,春季仍持续,且2009年前一年冬季赤道中东太平洋SSTA为拉尼娜位相,2009年春季明显减弱;2009年6-7月夏季东北冷涡活动异常强与4-5月500 hPa北太平洋地区超长波扰动转为定常波扰动槽有关;SVD和谐波分析表明,北太平洋涛动的异常位相不仅是东北夏季气温变化的重要前期信号,还是大气中除了天气尺度的混沌分量外可提取的一种行星尺度稳定分量.  相似文献   

Relationship Between the Western Pacific Subtropical High and the Subtropical East Asian Diabatic Heating During South China Heavy Rains in June 2005          下载免费PDF全文

WANG Lijuan  GAO Hui  GUAN Zhaoyong  HE Jinhai 《Acta Meteorologica Sinica》2011,25(2):203-210

Based on the daily NCEP/NCAR reanalysis data, the position variation of the western Pacific subtropical high (WPSH) in June 2005 and its relation to the diabatic heating in the subtropical East Asia are analyzed using the complete vertical vorticity equation. The results show that the position variation of the WPSH is indeed associated with the diabatic heating in the subtropical East Asian areas. In comparison with June climatology, stronger heating on the north side of the WPSH and relatively weak ITCZ (intertropical convergence zone) convection on the south side of the WPSH occurred in June 2005. Along with the northward movement of the WPSH, the convective latent heating extended northward from the south side of the WPSH. The heating to the west of the WPSH was generally greater than that inside the WPSH, and each significant enhancement of the heating field corresponded to a subsequent westward extension of the WPSH. In the mid troposphere, the vertical variation of heating on the north of the WPSH was greater than the climatology, which is unfavorable for the northward movement of the WPSH. On the other hand, the vertical variation of heating south of the WPSH was largely smaller than the climatology, which is favorable for the anomalous increase of anticyclonic vorticity, leading to the southward retreat of the WPSH. Before the westward extension of the WPSH in late June 2005, the vertical variation of heating rates to (in) the west (east) of the WPSH was largely higher (lower) than the climatology, which is in favor of the increase of anticyclonic (cyclonic) vorticity to (in) the west (east) of the WPSH, inducing the subsequent westward extension of the WPSH. Similar features appeared in the lower troposphere. In a word, the heating on the north-south, east-west of the WPSH worked together, resulting in the WPSH extending more southward and westward in June 2005, which is favorable to the maintenance of the rainbelt in South China.  相似文献   

Virtue and vulnerability: Discourses on women, gender and climate change   总被引：1，自引：0，他引：1  

Seema Arora-Jonsson 《Global Environmental Change》2011,21(2):744-751

In the limited literature on gender and climate change, two themes predominate - women as vulnerable or virtuous in relation to the environment. Two viewpoints become obvious: women in the South will be affected more by climate change than men in those countries and that men in the North pollute more than women. The debates are structured in specific ways in the North and the South and the discussion in the article focuses largely on examples from Sweden and India. The article traces the lineage of the arguments to the women, environment and development discussions, examining how they recur in new forms in climate debates. Questioning assumptions about women's vulnerability and virtuousness, it highlights how a focus on women's vulnerability or virtuousness can deflect attention from inequalities in decision-making. By reiterating statements about poor women in the South and the pro-environmental women of the North, these assumptions reinforce North-South biases. Generalizations about women's vulnerability and virtuousness can lead to an increase in women's responsibility without corresponding rewards. There is need to contextualise debates on climate change to enable action and to respond effectively to its adverse effects in particular places.  相似文献