A statistical approach for determining the environment impact of surface sediments from the Dongting Lake area,central China   总被引：1，自引：1，他引：0  

YAO Zhigang    BAO Zhengyu  ZHOU Lifa    GAO Pu Key Laboratory of Continental Dynamics  Ministry of Education/Department of Geology  Northwest University  Xi’an  China School of Petroleum Resources  Xi''an Shiyou University  Xi''an  China State Key Laboratory of Geological Processes  Mineral Resources  China University of Geosciences  Wuhan  China 《中国地球化学学报》2009,28(1):97-104

The Dongting Lake, the second biggest freshwater lake in China, consists of three wetlands of national importance, namely the East Dongting Lake, the South Dongting Lake, and the West Dongting Lake. Surface sedi-ments were sampled from 57 locations across the lake. Nutrient concentrations [total organic carbon (TOC), total N (TN) and total P (TP)] and 16 element concentrations (Al, As, B, Ca, Cd, Cr, Cu, K, Fe, Hg, Mn, Ni, Pb, Si, Ti and Zn) in the sediments were measured to investigate the impact of industrialization along the lake's coastline and sev-eral tributaries on the profiles of nutrients and heavy metals in the lake's surface sediments. R-mode cluster analysis (CA) was used to integrate geochemical data. The result showed that euthophication of the Dongting Lake resulted mainly from TN and TOC. The main polluting trace metals are Hg, As, Cd, Zn, Pb and Mn, which are largely ad-sorbed on clay minerals or Fe/Mn oxides, or deposited as carbonates. Principal component analysis (PCA) revealed the source of micropollutants. The worst affected district by heavy metals is the East Dongting Lake, the pollution sources may originate mainly from the Xiangjiang drainage area. The results demonstrated that multivariate methods are the potentially great tools for the interpretation of the environmental data on lake sediments.  相似文献   

广东省冬季逐日最低气温的预报方法     

翁向宇  纪忠萍  曾沁 《广东气象》2010,32(5):1-4

为了能结合数值预报产品做好广东省逐日最低气温的预报,利用1998~2007年冬季(11月~次年2月)美国NCEP/NCAR再分析资料和常规气象观测资料,选取20°~27.5°N,107.5°~117.5°E区域内的海平面气压、850 hPa温度、850 hPa相对湿度、850 hPa纬向风(u)、850 hPa经向风分量(v)和500hPa位势高度等6个要素作为预报因子,以韶关、梅州、广州、阳江、汕头等5个站分别作为广东5个部分的代表站,采用能选取"最优"因子的逐步回归方法建立5个代表站的11月~次年2月逐日的最低气温预报方程,并对预报方程进行检验。结果表明:采用逐步回归预报方法建立的广东省5个代表站的逐日最低气温预报方程具有一定的预报能力,但也存在预报结果比实况偏低的不足。  相似文献   

江黄颡(Pelteobagrus vachelli)和乌苏里拟鳞(Pseudobagrus ussuriensis)杂交F1代形态差异   总被引：1，自引：0，他引：1  

蔡永祥  陈友明  陈校辉  王明华  潘莹  夏爱军 《湖泊科学》2011,23(2):264-270

通过测定江黄颡雌、雄亲本,乌苏里拟鲿雌、雄亲本以及它们的正交F1代和反交F1代共6个实验鱼组合的形态和框架数据,运用卡方分析和多无分析方法,比较了杂交F1代与亲本之间的形态异同.可数性状卡方分析结果表明正、反交F1代与双亲在大部分可数性状上是一致的.但在胸鳍鳍条数上存在明显差异,胸鳍鳍条数可以作为区别杂交F1代与双亲的...  相似文献   

灵北断裂带黄埠岭-七里山段构造地球化学找矿预测     

陈艳  杨斌  王慧  梁恩云  刘海钢 《矿产与地质》2011,25(2):148-151

采用构造地球化学方法,在黄埠岭-七厘山测区约13.8km2范围,共采集865个样品,测试了Au、Ag、Cu、Pb、Zn、Ni、Ni、Co、Mo、Sn、As、Sb、Hg、Ba、B、Mn、V、Ti、Cr等19种元素.Au异常的分布与测区已知矿体分布范围相吻合,其中黄埠岭测区Au异常范围最大、强度最高,七厘山测区及凤凰庄-选...  相似文献   

The multivariate controls of hydraulic geometry: A causal investigation in terms of boundary shear distribution     

He Qing Huang  Robin F. Warner 《地球表面变化过程与地形》1995,20(2):115-130

Most downstream hydraulic geometry exponents have been found to be very close to the classic values reported by Leopold and Maddock (1953). These have been viewed as the simplified cases to general trends because the hydraulic geometry of alluvial channels is actually the product of ‘multivariate controls’ (Richards, 1982). This paper is an attempt to develop a soundly based foundation for the explanation of the physical mechanisms of these controls. A quantitative relationship between channel shape and boundary shear distribution developed from experimental flume results is found to be applicable in some instances to alluvial channels, particularly to stable canals. On the basis of this relationship, it is shown that downstream hydraulic geometry is determined not only by flow discharge, but also by channel slope, channel average roughness and sediment composition of the channel boundary. This is strongly supported by our analysis of 529 observations from both stable canals and natural rivers in the U.S.A. and the U.K. The difference between regime relations in canals and the hydraulic geometry of rivers appears to be caused mainly by channel slope and average roughness, which can be regarded as constants only in stable canals. The close relationship between discharge and channel average roughness observed in canals is not repeated in natural channels, partly because of the variety of flow values used to define the channel-forming discharge. Furthermore, it is indicated that the effects of the sediment composition of the channel boundary on hydraulic geometry are significant and need further investigation.  相似文献   

桤木人工林结瘤固氮的时空变化及其对后续植物的效应(Ⅱ)     

邓廷秀  刘国凡 《山地学报》1996,(Z1)

桤木人工林在山丘区的根瘤固氮活性3～6μmol/(g·h),活性受多种因素影响,变幅相当大,而变化规律仍明显.五年生桤木固氮量1～4mg/(株·h).固氮量取决于结瘤量,pH和质地亦影响显著.壤质的低钙质紫色土固氮能力较高,重壤质的酸性紫色土和黄壤固氮能力较低.十年生桤木林采伐迹地上,桤木固氮改良土壤,并促进后续植物的生长.  相似文献   

对应聚类分析     

纪宏金  吴锡生  陈永清 《吉林大学学报(地球科学版)》1993,(4)

对应聚类分析是一种多元统计分析方法。它吸取了对应分析和聚类分析的主要优点,在充分利用多维空间信息的基础上,该方法将变量类别、样品类别和它们间的对应关系清晰显示于单—图件,即对应聚类谱系图。近年来的许多实例说明该方法在地质和勘查地球化学中的应用是有成效的。本文详细叙述了对应聚类分析的计算方法,通过一些验证性实例介绍了方法效果,并简要讨论了为什么能获得较好效果的原因。  相似文献   

Cluster analysis of seismic moment tensor orientations   总被引：1，自引：0，他引：1  

Raymond J. Willemann 《Geophysical Journal International》1993,115(3):617-634

This paper demonstrates that well-known methods of cluster analysis and multivariate data analysis are useful for geodynamic interpretation of seismic moment tensors. To use these methods, moment tensors are expressed as vectors in a 6-D space. These are vectors in a rigorous sense, rather than an arbitrary set of ordered numbers, because a dot product can be defined that is independent of the coordinate system. In this vector space, non-isotropic moment tensors are a 5-D linear subspace and normalized moment tensors are unit vectors, or points on a unit sphere. Distance along a great circle of the unit sphere satisfies reasonable requirements for any measure of the difference between normalized moment tensors. In regions with a few isolated sets of orientations, cluster analysis based on the great circle distance identifies the same groups of earthquakes that a seismologist would. Figures based on principal component analysis and discriminant analysis illustrate orientation clustering better than equal area projections of moment tensor principal axes. In one case where clusters have been claimed to exist, orientations appear to be continuously distributed and no evidence is found for separate populations of moment tensors.  相似文献   

Universal cokriging under intrinsic coregionalization     

Jeffrey D. Helterbrand  Noel Cressie 《Mathematical Geology》1994,26(2):205-226

Under the intrinsic coregionalization model if both primary and secondary measurements are available at all sample locations, the conventional geostatistical wisdom is that cokriging provides exactly the same solution as univariate kriging on the primary process alone. However, recent eamples have been given where nonzero secondary cokriging weights have accurred under this spatial dependence structure. This note identifies the conditions under which secondary information is useful under the assumption of intrinsic coregionalization. An illustration is given using a dataset of plutonium and americium concentrations collected from a region of the Nevada Test Site.  相似文献   

灰色理论和回归分析组合模型在变形分析中的应用     

马苑菲  文鸿雁 《地理空间信息》2013,11(1):111-113,14

从GM(1,1)和多元回归分析模型出发,建立了灰色理论和回归分析组合模型。经过实验检验可知,灰色理论和回归分析组合模型有着良好的拟合预测能力,是一种有效的变形分析模型。  相似文献