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Showing 3 results for Mixing Model
Sediment Sources Fingerprinting: Relation between Enzyme Activities in Soil and Sediment
K. Nosrati, H. Ahmadi, F. Sharifi,
Volume 16, Issue 60 (7-2012)
Abstract
Sediment sources fingerprinting is needed as an autonomous tool for erosion prediction, validation of soil erosion models, monitoring of sediment budget and consequently for selecting soil conservation practices and sediment control methods at the catchment scale. Apportioning of eroded-soil into multiple sources using natural tracers is an integrated approach in soil erosion and sediment studies. The objectives of this study, as a first work, are to assess spatial variations of biochemical tracers and theirs validation in discriminating sediment sources under different land uses and water erosions at catchment scale and to apply them as fingerprints to determine relative contributions of sediment sources in Zidasht catchment, Iran. In view of this, 4 enzyme activities as biochemical tracers were measured in 42 different sampling sites from four sediment sources and 14 sediment samples. The results of discriminant function analysis (DFA) provided an optimum composite of two tracers, i.e. urease and dehydrogenase that afforded more than 92% correct assignations in discriminating between the sediment sources in the study area. Sediment source fingerprinting model was used based on optimum composite of two tracers resulting from DFA to explore the contributions of sediment from the four sources. The results showed that the relative contributions from rangeland/surface erosion, crop field/surface erosion, stream bank and dry-land farming/surface erosion sources were 11.3±5.3, 8.1±3.8, 75±8.5 and 3.6±2.5, respectively. Therefore, we can conclude that fingerprinting using biochemical tracers may help develop sediment fingerprinting models and as a first step facilitate a more complete tool for fingerprinting approach in the future.
Determination of Sub-Basin Contribution in Sediment Yield using Magnetic Susceptibility Properties and Uncertainty Mixing Model (Case Study: Ashan Drainage Basin, Maragheh County)
K. , and M. R. Nosrati, M. Amini, A. Haddadchi, Zare3,
Volume 20, Issue 78 (1-2017)
Abstract

Accelerated soil erosion in Iran causes on-site and off-site effects and identifying of sediment sources and determination of their contribution in sediment yield is necessary for effective sediment control strategies in river basin. In spite of increasing sediment fingerprinting studies uncertainty associated with magnetic susceptibility properties has not been fully incorporated in models yet. The objective of this study is determination of the relative contribution of sediment sources using magnetic susceptibility properties (High frequency, Low frequency and Frequency dependence) incorporated in uncertainty mixing model. For this purpose, 25 bed sediment samples were collected from the outlet of drainage basin and outlet of sub-basins and their magnetic susceptibility was measured and calculated. The results of Kruskal–Wallis test and discriminant function analysis showed that magnetic susceptibility properties can be used as optimum set of tracers in the uncertainty mixing model. The results of Bayesian mixing model indicated that mean (uncertainty range) relative contribution of Sparan, Joyband and Boyoukchay are 92 (83.9-94.8), 2.8 (0.2-10.7), 5.7 (0.2- 10.5) percent, respectively. According to these results, the highest amount of sediment yield is related to Sparan sub-basin and these results could be used in soil conservation and management planning.


Source Identification of Aerosols in Atmosphere Using Geochemical Properties of Tracer Elements (The Case Study Area: City of Kermanshah)
Z. Nazari, N. Khorasani, S. Feiznia, M. Karami,
Volume 22, Issue 1 (6-2018)
Abstract
The purpose of this research was source identification of aerosols in atmosphere using geochemical properties in the city of Kermanshah. The concentrations of twenty elements consisting of K, Na, Ca, P, Cu, Ni, Pb, Cd, Se, Zn, Fe, Mg, B, Cr, Co, As, Mo, V were analyzed by ICP for 55 soil samples (in the height range of 600-1600m) and 41 aerosols samples. Source identification of aerosels using geochemical tracers was performed in two steps. In the first step, appropriate combination of tracer elements with high ability in the resolation of aerosol sources was chosen using the means comparison test and discriminate analysis. In the second step, the multivariate mixing model was used to determine the contribution of aerosol sources (geological and geomorphology types) to the production of aerosols in the study area. The results obtained from determination of the contributions of sources of aerosols (geological and geomorphological types) showed the UF formation (consisting of red marl and sandstone), with the height of 0-1400 mand the slope of 0-5%, could be regarded as the main contributor to the production of aerosols located in the city of Qasreshirin.

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