和田地震台阵勘址测量与数据分析   总被引：1，自引：1，他引：0  

段天山  范广超 《地震地磁观测与研究》2009,30(5):96-100

介绍了新疆和田地震台阵候选台址现场勘址测量及后续数据处理分析等内容,为确定台阵的最终台址和子台布局提供了可靠的数据基础。  相似文献   

不同郁闭度天山云杉林林冠截留量及穿透雨量特征研究   总被引：3，自引：0，他引：3  

郝帅  张毓涛  刘端  张洪亮  李翔 《干旱区地理》2009,32(6)

天山云杉(Picea schrenkiana var.tianschanica(Rupr.)Chen et Fu)是构成天山山地森林生态系统的主体。选取天山森林生态系统定位研究站不同郁闭度天山云杉林作为研究对象,研究了不同郁闭度条件下天山云杉林冠截留量及穿透雨量的月变化特征、林冠截留量及穿透雨量与总降雨量间的数量关系,通过研究得出结论:林冠截留率与郁闭度表现出显著正相关关系,而穿透雨比率与郁闭度表现出显著负相关关系;穿透雨量、穿透雨比率及林冠截留量的月变化与总降雨量基本一致,林冠截留率则相反;郁闭度为0.8和0.6、0.4和0.2之间的穿透雨量无显著性差异,0.8和0.6与0.4和0.2之间差异明显,林冠截留量相邻郁闭度间均无显著性差异,而不相邻郁闭度之间均差异显著;建立了穿透雨量及林冠截留量与总降雨量间的数学关系,用以定量评价该地区天山云杉林水文生态效益。  相似文献   

长江三角洲地区经济极化趋势、功能及扩展范围   总被引：2，自引：2，他引：0  

段学军  虞孝感  Josef Nipper 《地理学报(英文版)》2009,19(6):733-749

In the era of economic globalization, the concept of Economic Polarized Area comes into being as an effective vehicle to agglomerate the economic elements and sustain the economic lifeline of the region. Based on the region’s specific development mode and construction form the concept is working in such a way that it will contribute to guide the economic development of the country and will play an important role in competing with other regions or countries in the world. Due to the high speed development of the last 30 years, the Yangtze Delta Region starts to show the features of Economic Polarized Area. But, compared with other world-class Economic Polarized Areas, the economic strength and the ability of the Yangtze Delta Region to drive the country’s economic development is still very low and the competitive power is still very limited. Expanding the boundaries of the Economic Polarized Area of the Yangtze Delta may extend the economic hinterland of the core area of the Yangtze Delta Region, will lighten the pressures from the limited resource and promote the rationalization of the industrial structure in the Yangtze Delta Region’s core area. With regard to the reasonable boundaries of the Yangtze Delta Region, there are different opinions and controversial arguments in political and academic circles. Starting from the idea of increasing the competitive power and improving the economic strength of the Yangtze Delta Region, the paper firstly is discussing the requirements to become a world-class Economic Polarized Area. In a second step an analysis of functional complementation and economic collaboration between the cities of an “extended” Yangtze Delta Region has been carried out by in particular considering the feasibility of integrating these “newly included” cities. The final result of the study is, that the Region should be expanded from the number of 16 cities to 37 cities, and the appended cities should be divided up into two categories: Wenzhou, Jinhua, Yancheng, Huaian, Maanshan, Wuhu, Tongling, Chaohu, Hefei, Chuzhou, Xuancheng should be taken as Preferred Extending Area, and Suqian, Xuzhou, Lianyungang, Lishui, Quzhou, Chizhou, Anqing, Bengbu, Huangshan, Suzhou (Anhui Province) should be taken as Retained Qualification Area.  相似文献   

Control of atmospheric CO<Subscript>2</Subscript> concentrations by 2050: A calculation on the emission rights of different countries   总被引：1，自引：0，他引：1  

ZhongLi Ding  XiaoNan Duan  QuanSheng Ge  ZhiQiang Zhang 《中国科学D辑(英文版)》2009,52(10):1447-1469

This paper is to provide quantitative data on some critical issues in anticipation of the forthcoming international negotiations in Denmark on the control of atmospheric CO2 concentrations. Instead of letting only a small number of countries dominate a few controversial dialogues about emissions reductions, a comprehensive global system must be established based on emissions allowances for different countries, to realize the long-term goal of controlling global atmospheric CO2 concentrations. That a system ...  相似文献   

深海现代沉积有机质碳同位素组成变化的古气候证据   总被引：2，自引：0，他引：2  

段毅  罗斌杰 《海洋地质与第四纪地质》1998,18(4):53-58

分析了南沙海洋深海连续沉积岩心剖面中有机碳同位素,研究了只有机质碳同位素组成变化因素及其与古气候旋回的关系,各种有机地球化学指标综合判识表明,该岩心剖面沉积有机质碳同位素组成变化未受有机质性质和成岩作用的影响,主要与古气候变迁关系密切。其ε＾１３Ｃ低值段对应于晚第四纪末次冰期,高值段对应于末次间冰期。  相似文献   

Preliminary study on the sea level change and its long-term prognostic method for Shanghai     

Qin Zenghao  Li Yongping  Duan Yihong 《海洋学报(英文版)》1998,17(1):27-39

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Trends in sunshine duration and atmospheric visibility in the Yunnan-Guizhou Plateau, 1961–2005     

XiaoBo Zheng  TianLiang Zhao  YuXiang Luo  ChangChun Duan  Juan Chen 《寒旱区科学》2011,3(2):0179-0184

Using the observed data from 184 stations over the Yunnan-Guizhou Plateau (YGP) from 1961 to 2005, the long-term trends in sunshine duration, cloud amount, dry visibility (Vd), dry extinction, and water vapor over the YGP are analyzed. The results show that 85% of the stations recorded shortening annual sunshine duration, with the decrease rates between ?12.2 and ?173.7 h/10yr. Results of Mann-Kendall tests indicate that, among the stations with decreasing sunshine duration, 63.7% of them experienced an abrupt change that started in the 1970s and peaked in the 1980s. This decreasing trend has reversed in the early years of the 21st century. The cloud cover and water vapor content in the mid and lower levels over the YGP had no obvious changes during the study period. The annual averages of Vd declined from 34 km in the 1960s to 27 km at present. The annual mean dry extinction coefficient trended upward, from 0.176 to 0.190, on the YGP from 1980 to 2005. Analyses of cloud cover, water vapor, atmospheric visibility, and dry extinction coefficient revealed that emitted tropospheric aerosols (including air pollutants) resulting from increased energy consumption over the YGP could be a major factor influencing the reductions of sunshine duration and atmospheric visibility.  相似文献   

Geochemical records of decadal variations in terrestrial input and recent anthropogenic eutrophication in the Changjiang Estuary and its adjacent waters   总被引：2，自引：0，他引：2  

Yu Yu  Jinming Song  Xuegang Li  Liqin Duan 《Applied Geochemistry》2012

Increasing eutrophication and seasonal anoxia in bottom water in the Changjiang Estuary and its adjacent waters has progressed in recent decades, caused by elevated anthropogenic N and P input. Sedimentary biogenic elements were investigated to determine whether the biogenic proxies could be used in paleoenvironmental studies in an energetic estuary, as well as to reconstruct the histories of environmental changes in the East China Sea (ECS). Two ²¹⁰Pb-dated cores from the coastal and offshore waters were analyzed for organic C (TOC) and its stable isotope (δ¹³C), total N (TN), biogenic Si (BSi), total P (TP) and P species. In coastal sediment, the variations of P species, especially Fe-P, Al-P and detrital apatite P (Det-P), reflected the dry–wet oscillations in the Changjiang River for the past century, which has influenced the sediment grain size and terrestrial material input. Much lower BSi content (0.756%) at 16–22 cm likely recorded the pronounced decrease in silicate flux in the Changjiang River and its lower flow in the late 1980s. In offshore sediment, higher concentrations of TOC, TN, BSi, Ex-P, Fe-P and Lea-OP indicated higher primary productivity in response to the strong winter monsoons during the 1960s–1980s, and their 20-a fluctuations were in agreement with the decadal variations of the winter monsoon. Low contents and little variations of Al-P and Det-P indicated the slight influence of the terrestrial sediment input in offshore waters. The influence of human activities on the environment in recent decades has also been recorded in coastal sediment. Grain-size normalized concentrations of TOC, TN, TP, Ex-P, Fe-P and Lea-OP increased by 24%, 23%, 15%, 13% and 51% in the upper 16 cm of coastal sediment, indicating elevated P and N load and primary productivity since the 1990s. Elevated TN/TP ratios and decreased BSi/TOC recorded the changed nutrient structure and the decrease in the proportion of the diatom to phytoplankton community. However, the sediment record indicated that the eutrophication might actually have started from the end of the 20th century rather than the reported middle of 20th century. In contrast, biogenic elements in offshore sediment did not reflect disturbance by human activities. This study revealed that multi-nutrient proxies in sediment in the ECS could indicate natural environmental changes including runoff and the winter monsoon over the past century, as well as the influence of human activities in recent decades. Phosphorus species with distinct origins and biogeochemical behaviors could effectively reflect different aspects of past environmental conditions.  相似文献   

Genesis and mineralization of gold-bearing quartz veins in the Xiao Qinling area, central China     

Jiwei Liang  Rongxi Li  Shaoni Zhang  Baoyun Chen  Lizhi Duan  Pierre Thibault 《中国地球化学学报》2012,31(4):441-448

Gold-bearing quartz veins of the Taihua Group consisting of Archean metavolcanic rocks are a main gold deposit type in the Xiao Qinling area,one of the three biggest gold production areas in China.The quartz veins experienced strong alteration characterized by a typical mesothermal hydrothermal altered mineral assemblage.The grade of gold is affected by the contents of sulphides,e.g.galena,pyrite and chalcopyrite.Results of minor elements analysis for the of gold-bearing quartz veins indicate higher contents of Au and high contents of Ag,Pb,Cu,Cd,W,and Mo.Abundant fluid inclusions were found in the gold-bearing quartz veins.Three types of fluid inclusions were identified:(1) aqueous inclusions;(2) CO 2-bearing inclusions;and(3) daughter crystal-bearing fluid inclusions.Homogenization temperatures ranged from 110 to 670℃ with low and high peaks appearing at 160 180℃ and 280 300℃,respectively.The salinity of aqueous inclusions varies between 1.8 wt% and 38.2 wt% NaCl.The homogenization temperature and salinity show a positive correlation.The H and O isotopes of fluid inclusions in the gold-bearing quartz veins indicate that magmatic solution and metamorphic hydrothermal solution,together with meteoric water,were involved in the formation of gold-bearing fluid.Mesozoic magma activities related to granite intrusions should be the main source of CO 2 fluid with higher temperature and salinity.  相似文献   

遵义市近10 a来降温频次及强度分析     

李霞  杨熠  田端  武正敏  肖蕾 《中低纬山地气象》2021,45(4):74-79

选取遵义市13个国家站2010—2019年逐日日最低气温资料,将降温过程分为弱降温、较强降温、强降温、寒潮4个等级,分析了各级降温过程的频次、持续日数、降温幅度、过程最低气温、空间分布等特征。分析表明：① 10 a来遵义市共发生降温过程11 915站次,平均每站每年91.7次,以降温幅度在6 ℃以下的弱降温为主。②近10 a遵义市平均过程降温幅度为3 ℃,平均过程最低日低温11.9 ℃,持续时间在1~10 d之间,寒潮、强降温、较强降温持续天数以2~3 d为主,弱降温过程大多持续1 d。③不同等级降温频次空间分布与地形相关,较强降温以上的降温过程主要集中出现在遵义市娄山以南地区,弱降温主要出现在娄山山区及其西北部。④寒潮、强降温、较强降温主要出现在春秋季,寒潮主要出现在3月份,而弱降温在夏季发生频次较高,4月份是遵义市降温最剧烈的时候。  相似文献