Role of landscape parameters in riverine run-off,and sediment and organic matter yield on Disko Island,West Greenland     

Morten Rasch  Niels Nielsen  Christian Christiansen  Thomas Balstrøm  Robert Gilbert  Joseph Desloges 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(2):1-11

Measurements of discharge and suspended sediment and organic matter yield from nine different drainage basins on the island Disko in central West Greenland were carried out in the period 19–30 July 1997. A series of landscape properties (glacier cover, altitude, slope, aspect and vegetation cover) were measured for each drainage basin from a digital elevation model and a satellite image. Principal Component Analysis and regression statistics have been used to examine which landscape parameters dominate the measured discharges and yields. It is concluded that differences in suspended sediment and organic matter yield between the drainage basins can be explained by the measured morphometric properties while differences in water run-off can not. Glacier cover percentage and percent area above 800 m a.s.l. were the most important parameters influencing suspended sediment and organic matter yield in the drainage basins on Disko during the study period.  相似文献   

Vital Statistics∗     

Mark Ellis 《The Professional geographer》2013,65(3):301-309

This article questions the idea that quantitative methods, in particular the analysis of social statistics, is at odds with critical approaches to geography. It argues that numbers-based research is vital to highlight social injustice and oppression and that quantitative research can meet the requirements of critical geography to be reflexive, politically conscious, and activist. The article highlights two issues of pressing interest for research and activism by critically inspired quantitative researchers. First, there should be vigilance about the retrenchment of data collection and releases by the state, which will end up obscuring the ability to see social inequalities. Second, there should be a vigorous challenge to the political and judicial undermining of the results of statistical sampling and inference. These are vital tools for estimating hard-to-count populations and inferring inequalities between groups. The article gives examples of where these estimation issues are critical, which include civilian deaths in Iraq, counting minority populations in the United States, and the detection and remediation of structural racism.  相似文献   

Complementary Use of Scalar,Directional, and Vector Statistics with an Application to Surface Winds     

《The Professional geographer》2013,65(1):3-13

Vector data are not uncommon in geography, and include examples such as transportation flows, particulate transport, and cartographic distortion. The directional and vector means and variances of these types of data are easily computed using a complex-arithmetic extension of the equations for scalar mean and variance. The January surface wind field over the contiguous United States provides an example with which to compare the information provided by scalar, directional and vector-based statistics. Spatial patterns of the mean and variance of January wind velocity (the wind vector) resemble patterns of wind speeds and directions but are not a simple superposition of the two, and one cannot necessarily infer the nature of the velocity field from separately computed salar and directional statistics. However, scalar and directional means and variances can lend insight into the features contributing to the velocity mean and variance. Scalar, directional, and vector-based analyses thus provide complementary methods with which to examine the spatial patterns of wind, or of any flow field that can be represented as a vector.  相似文献   

THE GEOGRAPHY OF MASTODON EXTINCTION     

《The Professional geographer》2013,65(4):425-429

Geographic Software Reviewed in this article:

LIFE TABLES and the LESLIE MATRIX. CONDUIT

MENTMAP2. Lawrence W. Carstensen Jr.

PC-MATLAB, Version 1.0. The Math Works, Inc.

QUICKMAP, version 1.0. Sammamish Data Systems, Inc.

SYSTAT: THE SYSTEM FOR STATISTICS, Version 2.1, Systat Inc.

USA DISPLAY. Instant Tecall  相似文献   

Updating estimates of low-streamflow statistics to account for possible trends     

Annalise G. Blum  Stacey A. Archfield  Robert M. Hirsch  Richard M. Vogel  Julie E. Kiang  Robert W. Dudley 《水文科学杂志》2013,58(12):1404-1414

ABSTRACT

Accurate estimators of streamflow statistics are critical to the design, planning, and management of water resources. Given increasing evidence of trends in low-streamflow, new approaches to estimating low-streamflow statistics are needed. Here we investigate simple approaches to select a recent subset of the low-flow record to update the commonly used statistic of 7Q10, the annual minimum 7-day streamflow exceeded in 9 out of 10 years on average. Informed by low-streamflow records at 174 US Geological Survey streamgages, Monte Carlo simulation experiments evaluate competing approaches. We find that a strategy which estimates 7Q10 using the most recent 30 years of record when a trend is detected, reduces error and bias in 7Q10 estimators compared to use of the full record. This simple rule-based approach has potential as the basis for a framework for updating frequency-based statistics in the context of possible trends.  相似文献   

高阶统计量在探地雷达数据处理中的应用     

谢尚平  张阔 《物探与化探》2012,(1):122-125,132

用高阶统计量方法对探地雷达数据进行处理,基本思路是采用信号识别与检测中的高阶统计量参数,对不同模型的探地雷达数据记录进行处理与重构,结果表明不同模型具有不同阶数的高阶统计量特征。模型实验与实际应用都表明,高阶统计量对压制背景噪声和多次反射波有较好的效果。  相似文献   

基于地理信息系统的空间统计学方法在地震统计中的应用     

廖微  姚琪  廖林  张微  姜祥华  杨文 《中国地震》2021,37(3):695-703

传统的地震统计学多局限于规则的统计范围,或是需要较多的人工干预,本文引入了基于地理信息系统的空间统计学方法,将其应用于地震空间统计中,能够高效、快速地挖掘含有地理信息的各要素之间的相互联系。本文以川滇地区2019年发生的ML≥1.0地震数量的空间统计为例,详述了对地震数据进行空间统计的流程。统计结果表明,0.5°×0.5°是最适合该地震数据集空间统计的矩形范围,发生地震次数最多的区域位于四川盆地西南缘的威远?长宁地区,此外龙门山断裂带、龙门山断裂带与鲜水河?小江断裂系交汇处、丽江?小金河断裂沿线以及滇南地区均为地震发生次数较高的区域。此外,还利用该方法计算了2015—2019年全国各省地震能量释放情况。结果显示在该时间段内,释放地震能量总量最多的省份为四川省,新疆维吾尔自治区和西藏自治区次之,而台湾地区陆地区域、四川省、西藏自治区等地区具有较高的每万平方公里地震能量释放量和每万人地震能量承受量。并通过上述应用实例,探索了地理信息系统在地震统计领域的初步应用。  相似文献   

统计预测技术的回顾和展望   总被引：1，自引：0，他引：1       下载免费PDF全文

马开玉 《热带气象学报》2003,19(4):436-441

对我国近几十年来的统计预测技术进行了回顾，并对未来的发展提出了一些看法。  相似文献   

1949-2007年登陆我国变性热带气旋的特征统计及合成分析   总被引：1，自引：2，他引：1  

袁娟娟  丁治英  王莉 《热带气象学报》2011,27(4):529-541

利用1949-2007年热带气旋年鉴等资料,统计分析登陆中国并在我国或附近变性的热带气旋的特征,着重分析不同区域及路径的变性气旋特征.分析结果得出,登陆我国的热带气旋很多,但在我国及附近沿海变性的却较少,大多数热带气旋变性后不发展或迅速衰减,只有约17％的变性热带气旋继续发展.热带气旋变性大多发生在114°E以东,移动...  相似文献   

REVIEWS OF GEOGRAPHIC SOFTWARE     

《The Professional geographer》1987,39(2):229-237

CHAOS CLlM 3.77 LP88 and TPR088 MAPEDIT PRODESIGN II RANDMAP SPATIAL AUTOCORRELATION SIMULATION GAME . Daniel A. Griffith STATA THINKTANK NOTEBOOK II  相似文献