一种由磁异常畸变分析估算总磁化方向的方法     

Fedi  M 王艳君 《物探化探译丛》1995,(1):2-8

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长江流域20cm蒸发皿蒸发量的时空变化   总被引：16，自引：3，他引：16       下载免费PDF全文

王艳君  姜彤  许崇育 《水科学进展》2006,17(6):830-833

利用长江流域107个气象站1951-2000年的20cm口径蒸发皿逐日蒸发资料,采用Mann-Kendall趋势检验法和IDW反距离权重空间插值法分析了近50年来,尤其是20世纪90年代长江流域的年和季节蒸发皿蒸发量的时空变化.50年来,长江流域以年平均、夏季和秋季蒸发皿蒸发量显著下降为主要特点,尤以20世纪90年代最为显著,是年平均和夏季蒸发皿蒸发量最小的时期,比前0年平均值分别低-25.9mm和-36.1mm,这种趋势中下游地区比上游地区明显得多,尤其是在鄱阳湖流域.  相似文献   

Large-scale immigration and political response: popular reaction in California     

Clark WA 《International journal of population geography : IJPG》1998,4(1):1-10

Over the past 3 years, the level of political debate has grown over the nature and extent of the recent large-scale immigration to the US in general, and to California in particular. California's Proposition 187 to deny welfare benefits to illegal immigrants brought national attention to the immigration debate, and no doubt influenced recent decisions to significantly change the US's welfare program. The author studied the vote on Proposition 187 in the November 1994 California election to better understand the nature of reaction to large-scale immigration and recent arguments about anti-immigrant sentiment and nativism. The only counties which voted against the proposition were Sonoma, Marin, San Mateo, Santa Cruz, Yolo, Alameda, and Santa Clara, as well as the population of San Francisco. The vote generated political responses from across the border as well as within California. Statements from Mexican and other Central American governments reflected their concern over the possibility of returning populations, for whom there are neither jobs nor public services in their countries of origin. Findings are presented from a spatial analysis of the vote by census tracts in Los Angeles County.  相似文献   

裂隙探测中钻孔磁性电阻率（MMR）评价     

Labr.  DJ  王艳君 《物探化探译丛》1989,(4):24-27

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北美东南部前寒武纪晚期至寒武纪Appalachian—Ouachita裂谷型边缘 …     

Thom.  WA 王义天 《国外地质与勘测》1995,(3):1-5,16

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RECENT DEVELOPMENTS IN MULTIVARIATE CALIBRATION   总被引：1，自引：0，他引：1  

B.R.KOWALSKI M.B.SEASHOLTZ Laboratory for Chemometrics  BG-  University of Washington  Seattle  WA  U.S.A. 《地理学报(英文版)》1991,(3)

With the goal of understanding global chemical processes,environmental chemists have some of the mostcomplex sample analysis problems.Multivariate calibration is a tool that can be applied successfully inmany situations where traditional univariate analyses cannot.The purpose of this paper is to reviewmultivariate calibration,with an emphasis being placed on the developments in recent years.The inverseand classical models are discussed briefly,with the main emphasis on the biased calibration methods.Principal component regression(PCR)and partial least squares(PLS)are discussed,along with methodsfor quantitative and qualitative validation of the calibration models.Non-linear PCR,non-linear PLSand locally weighted regression are presented as calibration methods for non-linear data.Finally,calibration techniques using a matrix of data per sample(second-order calibration)are discussed briefly.  相似文献   

WINTER RUNOFF AND EROSION ON NORTHWESTERN USA CROPLAND     

D.K. McCool 《国际泥沙研究》2000,(2)

h200l.llNTRODUCTI0NTheNorthwesternWheatandRangeRegi0n(NWax)(Austin,l98l),whichincludesportionsofIdaho,Oregon,andWashington,isoneofthem0stuniqueagriculturalregionsoftheUSA.Winterandspringsmallgrainsand0thercropsareproukcedonl0esss0ilsdepositedoverbasalt.TheloessvariesinboththicknessandtopograPhicfeatures.Someareashavesteepanddune-likeslopes,while0thershavel0ng,gentlesl0pes.Theregion,br0kenfromnativeprairielessthanl20yearsag0(Kaise,l96l)hassufferedseriousdegradationofthesoilresourcebyw…  相似文献   

Lessons learned from a suite of CFB Borden experiments     

Sudicky EA  Illman WA 《Ground water》2011,49(5):630-648

This article summarizes several of many field-based studies of subsurface contaminant transport conducted over the last 30 years at the Canadian Forces Base (CFB) Borden site. The field research initially consisted of extensive monitoring of a leachate plume from an abandoned landfill and its analytical and numerical modeling. Lessons learned from these initial studies led to the execution and interpretation of a variety of tracer tests involving conservative and reactive/organic solutes tests performed at various scales. The lessons learned from these tracer tests revealed a number of deficiencies in classical theories of contaminant dispersion and reaction processes as they occur in groundwater, and thus spawned a new era of process-oriented research within the hydrogeological community. The extensively monitored tracer tests were followed by controlled spills of organic contaminants to observe their subsurface movement and distribution as well as the emplacement of a variety of contaminant sources in the saturated and unsaturated zones to study the ambient transport of contaminants. The controlled spills and emplaced sources of various contaminants were then utilized for testing various active and passive remediation technologies. These studies have led to fundamental insights and lessons learned that have significantly contributed to research on contaminant transport in both the saturated and unsaturated zones. Over the years, data generated by the University of Waterloo (UW) researchers and their collaborators continues to be examined by various research groups and has led to additional new insights on subsurface transport of various chemicals.  相似文献   

基于CMIP6多模式的长江流域蒸散发预估及影响因素          下载免费PDF全文

詹明月  王国杰  陆姣  陈丽琴  朱晨霞  姜彤  王艳君 《大气科学学报》2020,43(6):1115-1126

蒸散发是水文循环和能量传输的中间环节,同时也是联结土壤、植被、大气过程的纽带。基于第六次国际耦合模式比较计划（CMIP6）12个全球气候模式数据,研究了SSP1-2.6、SSP2-4.5和SSP5-8.5三种情景下,长江流域2020-2099年实际蒸散发E_T（Evapotranspiration,简称ET）的时空变化及其影响因素。研究结果表明,在3种气候变化情景下长江流域ET相较基准期（1995-2014年）均存在显著增加趋势,且长江中下游地区增加趋势最为显著;SSP1-2.6情景ET较基准期先快速增加,21世纪60年代之后减缓并趋于平稳,SSP2-4.5和SSP5-8.5情景下均呈持续增加趋势。研究了降水（Precipitation,简称Pr）、气温（Air Temperature,简称T）和叶面积指数L_AI（Leaf Area Index,简称LAI）对长江流域ET的影响;SSP1-2.6和SSP2-4.5情景下,长江流域ET受T影响最为显著,而SSP5-8.5情景下,LAI是影响ET的主导因素。在3种气候情景下,辐射强迫越大,植被增加趋势越显著,对ET的影响越强（SSP5-8.5、SSP2-4.5、SSP1-2.6情景下影响逐渐减弱）,而ET对LAI的敏感性则逐渐降低（SSP1-2.6、SSP2-4.5、SSP5-8.5情景下敏感性逐渐降低）。  相似文献   

TENSORIAL RESOLUTION:A DIRECT TRILINEAR DECOMPOSITION   总被引：4，自引：0，他引：4  

EUGENIO SANCHEZ~ BRUCE R.KOWALSKI Laboratory for Chemometrics Department of Chemistry BG-.University of Washington  Seattle WA  U.S.A. Mobil Research  Development Corporation  Paulsboro Research Laboratory  Billinsport Ro  Paulsboro  NJ  U.S.A. 《地理学报(英文版)》1990,(1)

Modern instrumentation in chemistry routinely generates two-dimensional(second-order)arrays of data.Considering that most analyses need to compare several samples,the analyst ends up with a three-dimensional(third-order)array which is difficult to visualize or interpret with the conventional statisticaltools.Some of these data arrays follow the so-called trilinear model,(?)These trilinear arrays of data are known to have unique factor analysis decompositions which correspondto the true physical factors that form the data,i.e.given the array (?),a unique solution can be found inmany cases for each order X,Y and Z.This is in contrast to the well-known second-order bilinear datafactor analysis,where the abstract solutions obtained are not unique and at best cannot be easilycompared with the underlying physical factors owing to a rotational ambiguity.Trilinear decompositions have had the disadvantage,however,that a non-linear optimization withmany parameters is necessary to reach a least-squares solution.This paper will introduce a method forreducing the problem to a rectangular generalized eigenvalue-eigenvector equation where the eigenbectorsare the contravariant form(pseudo-inverse)of the actual factors.It is shown that the method works wellwhen the factors are linearly independent in at least two orders(e.g.X_(jr),and Y_(jr) are full rank matrices).Finally,it is shown how trilinear decompositions relate to multicomponent calibration,curve resolutionand chemical analysis.  相似文献