Geochemical multifractal distribution patterns in sediments from ordered streams

Abstract. Several studies have shown that vegetation indexes can be used to estimate root zone soil moisture. Earth surface images, obtained by high-resolution satellites, presently give a lot of information on these indexes, based on the data of several wavelengths. Because of the potential capacity for systematic observations at various scales, remote sensing technology extends the possible data archives from the present time to several decades back. Because of this advantage, enormous efforts have been made by researchers and application specialists to delineate vegetation indexes from local scale to global scale by applying remote sensing imagery.In this work, four band images have been considered, which are involved in these vegetation indexes, and were taken by satellites Ikonos-2 and Landsat-7 of the same geographic location, to study the effect of both spatial (pixel size) and radiometric (number of bits coding the image) resolution on these wavelength bands as well as two vegetation indexes: the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI).In order to do so, a multi-fractal analysis of these multispectral images was applied in each of these bands and the two indexes derived. The results showed that spatial resolution has a similar scaling effect in the four bands, but radiometric resolution has a larger influence in blue and green bands than in red and near-infrared bands. The NDVI showed a higher sensitivity to the radiometric resolution than EVI. Both were equally affected by the spatial resolution.From both factors, the spatial resolution has a major impact in the multi-fractal spectrum for all the bands and the vegetation indexes. This information should be taken in to account when vegetation indexes based on different satellite sensors are obtained.

Section: Multi-fractal Image Analysismentioning

confidence: 99%

Spatial and radiometric characterization of multi-spectrum satellite images through multi-fractal analysis

Alonso

Tarquis²,

Zúñiga

et al. 2017

“…The calculation of the mass exponent function τ (q) for the gliding-box method is different from the box-counting method, with the gliding-box method providing a useful approach that can increase the number of samples that are available for statistical estimation within a data set (Buczkowski et al, 1998;Tarquis et al, 2006;Xie et al, 2010). This means that the gliding-box approach often provides better results with lower uncertainties than the box-counting method (Cheng, 1999).…”

Section: Multifractal Spectrum Analysismentioning

confidence: 99%

Comparison of the multifractal characteristics of heavy metals in soils within two areas of contrasting economic activities in China

Li¹,

Li²,

Yuan³

et al. 2016

Abstract. Industrial and agricultural activities can generate heavy metal pollution that can cause a number of negative environmental and health impacts. This means that evaluating heavy metal pollution and identifying the sources of these pollutants, especially in urban or developed areas, is an important first step in mitigating the effects of these contaminating but necessary economic activities. Here, we present the results of a heavy metal (Cu, Pb, Zn, Cd, As, and Hg) soil geochemical survey in Hefei city. We used a multifractal spectral technique to identify and compare the multifractality of heavy metal concentrations of soils within the industrial Daxing and agricultural Yicheng areas. This paper uses three multifractal parameters ( α, f (α), and τ (1)) to indicate the overall amount of multifractality within the soil geochemical data. The results show all of the elements barring Hg have larger α, f (α), and τ (1) values in the Daxing area compared to the Yicheng area. The degree of multifractality suggests that the differing economic activities in Daxing and Yicheng generate very different heavy metal pollution loads. In addition, the industrial Daxing area contains significant Pb and Cd soil contamination, whereas Hg is the main heavy metal present in soils within the Yicheng area, indicating that differing clean-up procedures and approaches to remediating these polluted areas are needed. The results also indicate that multifractal modelling and the associated generation of multifractal parameters can be a useful approach in the evaluation of heavy metal pollution in soils.

“…Eight fractal and multifractal parameters have been calculated to characterize the spatial and τ (q) Vidal et al, 2008;Cheng, 1999;Xie et al, 2010b). In homogeneous structures, Dq are close to one another, whereas for a monofractal structure they are equal.…”

Section: Multifractal Analysismentioning

confidence: 99%

Assessing microstructures of pyrrhotites in basalts by multifractal analysis

Xie

Cheng

Zhang

et al. 2010

Abstract. Understanding and describing spatial arrangements of mineral particles and determining the mineral distribution structure are important to model the rock-forming process. Geometric properties of individual mineral particles can be estimated from thin sections, and different models have been proposed to quantify the spatial complexity of mineral arrangement. The Gejiu tin-polymetallic oreforming district, located in Yunnan province, southwestern China, is chosen as the study area. The aim of this paper is to apply fractal and multifractal analysis to quantify distribution patterns of pyrrhotite particles from twentyeight binary images obtained from seven basalt segments and then to discern the possible petrological formation environments of the basalts based on concentrations of trace elements. The areas and perimeters of pyrrhotite particles were measured for each image. Perimeter-area fractal analysis shows that the perimeter and area of pyrrhotite particles follow a power-law relationship, which implies the scaleinvariance of the shapes of the pyrrhotites. Furthermore, the spatial variation of the pyrrhotite particles in space was characterized by multifractal analysis using the method of moments. The results show that the average values of the area-perimeter exponent (D AP ), the width of the multifractal spectra ( (D(0) − D(2)) and (D(q min ) − D(q max ))) and the multifractality index (τ (1)) for the pyrrhotite particles reach their minimum in the second basalt segment, which implies that the spatial arrangement of pyrrhotite particles in Segment 2 is less heterogeneous. Geochemical trace element analysis results distinguish the second basalt segment sample from other basalt samples. In this aspect, the fracCorrespondence to: S. Xie (tinaxie2006@gmail.com) tal and multifractal analysis may provide new insights into the quantitative assessment of mineral microstructures which may be closely associated with the petrogenesis as shown by the bulk-rock geochemical analysis.