جستجوی مقالات مرتبط با کلیدواژه « Cokriging » در نشریات گروه « محیط زیست »

Isfahan is one of the most contaminated cities in Iran due to its special geographical conditions, topography and proliferation of pollutants. Industries, traffic, domestic and commercial pollutants are considered the main sources of air pollutants in Isfahan. The methods used to predict and estimate air pollution are methods interpolation. The aim of this study is to investigate the scattering patterns and modeling of particular matter PM2.5 and PM10 in the city of Isfahan using interpolation IDW and Cokriging methods.

in this study, the concentration of PM2.5 and PM10 pollutants in winter and summer of 2018 were measured at 137 points of urban area and in linear path by portable device measurement of air pollution (CEM model). Zoning maps for each pollutant in the cold and hot season were in Arc GIS 10.6 environment. In order to verify the accuracy of 30% of the data, the RMSE in both methods was compared.

the result of pollutants distribution with important emission sources, such as high traffic areas and close areas were consistent with the zayanderood river route. Cokriging method has better performance than IDW method in values of RMSE, although in the validation process, there was little difference between fitting the IDW and Cokriging methods.

in the zoning maps, hot spots of pollution (maximum concentration) were observed in central regions of the study area, which is a major contribution to most of the vehicles around the city.

Soil characteristics have spatial variations. Understanding spatial variations of soil characteristics is among the effective factors in sustainable land management. A better understanding the effects of management factors on soil characteristics need to quantify their heterogeneity and variability. This research was conducted with the aim of investigating spatial variations of some soil characteristics such as soil texture (clay, silt and sand), calcium carbonate (CaCo3), soil acidity (pH), and soil salinity using geostatistic methods. For this purpose, 252 soil samples (from 0 to 20 cm depth) were prepared from the study area and physical and chemical properties of soil were measured. After normalizing the data, the half-shift of each of the studied characteristics was calculated and the best model was fitted to them. Then, the characteristics of the study were estimated through different methods of conventional Kriging, simple Kriging, discrete Kriging and Inverse Distance Weighted (IDW) using ArcGIS software. The accuracy of the estimation was evaluated using the mean absolute error (MAE), the mean bias error (MBE), and the root mean square error (RMSE). The results showed that the best model for the acidity was the spherical model and for the other measured variables was the exponential model. Moreover, the conventional CoKriging method for clay, calcium carbonate and acidity (pH), IDW method for silt and soil salinity, and conventional Kriging method for sand were better than other methods used and provided more accurate estimates.

The aim of this study was to assess the efficiency of cokriging method in comparing to kriging to map biophysical properties of wild pistachio trees in Zagros forests. A 45 ha stand, covered with wild pistachio trees was chosen in FiroozAbad wild pistachio research site in Fars province. 87 circular plates with 800 m2 area were selected based on a 72 × 72 m2 grid. Biophysical properties (height, diameter at breast height, trees per ha, and canopy cover percent) of all wild pistachio trees were measured in each plot. Kriging and cokriging methods were then used to map each biophysical property. The results showed that mean error and root mean squared error of height, diameter at breast height, and trees per ha of cokriging method were less than kriging method. The regression coefficients of height, diameter at breast height, and trees per ha of cokriging method were also greater than the kriging method that showed the efficiency of the cokriging method in the improvement of estimation of trees’ biophysical properties. The amount of root mean squared error and regression coefficient were slightly better for canopy cover percent in kriging, though, they were not significant. In general, it was concluded that the maps of biophysical properties can be obtained with suitable accuracy and precision using Cokriging method.

Application of statistical techniques in applied sciences, especially in climatology and meteorology, are widespread and a common practice. This paper deals with the application of modern techniques such as kriging, co-kriging, and inverse–distance weighted for prediction of rainfall in places where there are not gauging facilities. The available data from all stations throughout the country, since their establishment to 2004, have been used to find the variogram and cross-variogram. Based on the best possible model, rainfall map for the country has been prepared.