Multivariate Correlation in the Framework of Support and Spatial Scales of Variability     

J. A. Vargas-Guzmáan  A. W. Warrick  D. E. Myers 《Mathematical Geology》1999,31(1):85-103

This paper extends the concept of dispersion variance to the multivariate case where the change of support affects dispersion covariances and the matrix of correlation between attributes. This leads to a concept of correlation between attributes as a function of sample supports and size of the physical domain. Decomposition of dispersion covariances into the spatial scales of variability provides a tool for computing the contribution to variability from different spatial components. Coregionalized dispersion covariances and elementary dispersion variances are defined for each multivariate spatial scale of variability. This allows the computation of dispersion covariances and correlation between attributes without integrating the cross-variograms. A correlation matrix, for a second-order stationary field with point support and infinite domain, converges toward constant correlation coefficients. The regionalized correlation coefficients for each spatial scale of variability, and the cases where the intrinsic correlation hypothesis holds are found independent of support and size of domain. This approach opens possibilities for multivariate geostatistics with data taken at different support. Two numerical examples from soil textural data demonstrate the change of correlation matrix with the size of the domain. In general, correlation between attributes is extended from the classic Pearson correlation coefficient based on independent samples to a most general approach for dependent samples taken with different support in a limited domain.  相似文献   

Erosion surfaces and ignimbrite eruption,measures of Andean uplift in northern Peru     

J. S. Myers 《Geological Journal》1976,11(1):29-44

Remnants of five mature erosion surfaces occur on the rugged western flank of the Andes, and each is deeply incised. They indicate alternation of arid with more humid conditions, and that the western Andes were raised in five major pulses from a subdued early Tertiary landscape of volcanic flows. Each pulse of uplift was accompanied by south-westward tilting of the older erosion surfaces. The surfaces developed before an ignimbrite was erupted down the ancestoral Rio Fortaleza valley 6 m.y. ago. Since then, renewed uplift has led to further incision of the main valleys and the formation of canyons.  相似文献   

Large‐scale regional delineation of riparian vegetation in the arid and semi‐arid Pilbara region,WA          下载免费PDF全文

Masoomeh Alaibakhsh  Irina Emelyanova  Olga Barron  Mehdi Khiadani  Garth Warren 《水文研究》2017,31(24):4269-4281

Multiscene Landsat 5 TM imagery, Principal Component Analysis, and the Normalized Difference Vegetation Index were used to produce the first region‐scale map of riparian vegetation for the Pilbara (230,000 km²), Western Australia. Riparian vegetation is an environmentally important habitat in the arid and desert climate of the Pilbara. These habitats are supported by infrequent flow events and in some locations by groundwater discharge. Our analysis suggests that riparian vegetation covers less than 4% of the Pilbara region, whereas almost 10.5% of this area is composed of groundwater dependent vegetation (GDV). GDV is often associated with open water (river pools), providing refugia for a variety of species. GDV has an extremely high ecological value and are often important Indigenous sites. This paper demonstrates how Landsat data calibrated to Top of Atmosphere reflectance can be used to delineate riparian vegetation across 16 Landsat scenes and two Universal Transverse Mercator spatial zones. The proposed method is able to delineate riparian vegetation and GDV, without the need for Bidirectional Reflectance Distribution Function correction. Results were validated using ground truth data from local and regional scale vegetation surveys.  相似文献   

Variance as a function of sample support size     

R. Zhang  A. W. Warrick  D. E. Myers 《Mathematical Geology》1990,22(1):107-121

The effect of sample support size on variance is examined and evaluated. Results based on variograms and geostatistics are compared to the classical relationship developed by H. F. Smith in 1938; that is, that the variance is reduced fromV ₁ toV ₁ /n ^b as the support area increases from I ton plots for uniformity trials. The exponentb is between zero and one. Theoretical results are based on use of auxiliary functions and account for the size and shape of the sample support and the overall field geometry. Results are given in terms of approximations by rational functions for ease of calculation. Experimental results for uniformity trials, infiltration measurements, and spectral data from satellites are compared to theoretical and empirical results. Applications include not only uniformity trials, but also measurement theory.  相似文献   

A statistical-mechanics model of ordering in aluminosilicate solid solutions     

Eva R. Myers 《Physics and Chemistry of Minerals》1998,25(6):465-468

A statistical-thermodynamic approximation for order-disorder phase transitions in aluminosilicate solid solutions is presented. The approximation involves estimating the number of configurations with long range order parameter Q and short range order parameter σ, using an approximation to the probability that a configuration with the correct amount of long range order will also have the correct amount of short range order. This estimate is then used to give a free energy F(Q, σ, x, T), where x is the concentration of Al in the structure, and hence quantities such as T _c (x) are estimated. The predictions of the model for T _c (x) and the critical concentration x _c at which T _c falls to zero are shown to be in good agreement with the results of Monte Carlo simulations. Received: 14 May 1997 / Revised, accepted: 2 June 1997  相似文献   

In search of thresholds for recruitment overfishing   总被引：2，自引：0，他引：2  

Myers  R. A.; Rosenberg  A. A.; Mace  P. M.; Barrowman  N.; Restrepo  V. R. 《ICES Journal of Marine Science》1994,51(2):191-205

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Toxicopathic liver lesions in English sole and chemical contaminant exposure in Vancouver Harbour,Canada     

Stehr CM  Myers MS  Johnson LL  Spencer S  Stein JE 《Marine environmental research》2004,57(1-2):55-74

The prevalence of toxicopathic liver lesions in English sole (Pleuronectes vetulus) was determined along a presumed gradient of chemical contamination in Vancouver Harbour, Canada. Fish were captured from five sites in or near Vancouver Harbour, British Columbia, Canada. No toxicopathic lesions were observed in fish examined at the reference site (Howe Sound outside Vancouver Harbour), or at the outer harbour site. In contrast, 20-23% of the fish from three sites located in the central harbour, Indian Arm and Port Moody Arm had one or more types of toxicopathic lesions. Likewise, aromatic hydrocarbon (AH) metabolites measured in bile exhibited a gradient in levels from lower concentrations at the reference site to significantly higher levels in fish from Indian Arm and Port Moody Arm harbour sites. The occurrence of toxicopathic liver lesions was statistically associated with concentrations of AHs measured in sediment and AH metabolite levels measured in bile.  相似文献   

Evolution of Baffin Bay Water Masses and Transports in a Numerical Sensitivity Experiment under Enhanced Greenland Melt     

Nathan Grivault  Xianmin Hu  Paul G. Myers 《大气与海洋》2017,55(3):169-194

We used a numerical model forced with three different scenarios to analyze Baffin Bay circulation sensitivity to runoff around Baffin Bay, especially the Greenland runoff, for the past (1970–2010) and future (2010–2099). We observed an overall decrease in transport from the Arctic to the North Atlantic for the volume, heat, and freshwater over the time period as well as an augmentation of the freshwater and heat in Baffin Bay. In the early 1990s, the increase in heat in Baffin Bay was consistent with an increase in the West Greenland Irminger Water (WGIW) inflow at Davis Strait while later West Greenland Shelf Water played an important role in the heat import, sustaining the idea that the West Greenland Current might have an impact on the melt of West Greenland tidewater glaciers. The increase in freshwater and later in heat in Baffin Bay leads to changes in the steric height inside Baffin Bay, which leads to changes in the circulation. After 1978, the WGIW reaches the North Water polynya and recirculates into the Baffin Bay gyre where it accumulates over time. In the future experiment, the dynamic changes in Baffin Bay are mainly related to the accumulation of heat inside the gyre.  相似文献   

Integration of airborne thematic mapper simulator (TMS) data and digitized aerial photography via an ISH transformation     

Vincent G. Ambrosia  Jeffrey S. Myers  Robert E. Ekstrand  Michael T. Fitzgerald 《国际地球制图》2013,28(2):45-48

Abstract

In water sampling it is very common to use human experience to determine sampling locations. We present results from a neural network analysis of multispectral imaging data from the Compact Airborne Spectrographic Imager (casi) to determine significant water sampling locations. In this study Lake Tegel in Berlin, Germany, was overflown on different days. The analysis of the remote sensing data results in a clustering of the overflown water body for each pass. The neural network clusters found for each pass have been related to each other. This procedure enables us to optimize the number and location of water sampling stations.  相似文献   

Recognizable primary volcanic and sedimentary features in a low-strain domain of the highly deformed, oldest known (≈ 3.7–3.8 Gyr) Greenstone Belt, Isua, West Greenland     

Appel  Fedo  Moorbath  & Myers 《地学学报》1998,10(2):57-62

A low-strain domain has been identified in the metamorphosed, mostly highly deformed volcanic and sedimentary rocks of the early Archaean Isua supracrustal belt. This domain contains well-preserved volcanic and sedimentary features, including basaltic pillow lavas, pillow breccia, heterogeneous volcanic breccia, amygdules in metabasalt, and polymict conglomerate dominated by recrystallized chert and volcanic clasts. The low-strain domain is bounded by highly deformed rocks mostly derived from basalt, chert, and banded iron formation. These discoveries demonstrate that some primary features have escaped the pervasive metasomatism dominant in other parts of the belt and, furthermore, strengthen the characterization of the Isua supracrustals as a typical greenstone belt.  相似文献