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31.
Comparison of artificial neural network and multivariate linear regression methods for estimation of daily soil temperature in an arid region 总被引:5,自引:0,他引:5
Hossein Tabari Ali-Akbar Sabziparvar Mohammad Ahmadi 《Meteorology and Atmospheric Physics》2011,110(3-4):135-142
Soil temperature (T S) strongly influences a wide range of biotic and abiotic processes. As an alternative to direct measurement, indirect determination of T S from meteorological parameters has been the focus of attention of environmental researchers. The main purpose of this study was to estimate daily T S at six depths (5, 10, 20, 30, 50 and 100?cm) by using a multilayer perceptron (MLP) artificial neural network (ANN) model and a multivariate linear regression (MLR) method in an arid region of Iran. Mean daily meteorological parameters including air temperature (T a), solar radiation (R S), relative humidity (RH) and precipitation (P) were used as input data to the ANN and MLR models. The model results of the MLR model were compared to those of ANN. The accuracy of the predictions was evaluated by the correlation coefficient (r), the root mean-square error (RMSE) and the mean absolute error (MAE) between the measured and predicted T S values. The results showed that the ANN method forecasts were superior to the corresponding values obtained by the MLR model. The regression analysis indicated that T a, RH, R S and P were reasonably correlated with T S at various depths, but the most effective parameters influencing T S at different depths were T a and RH. 相似文献
32.
Ghourchaei Shemshad Ghasemi-Nejad Ebrahim Vahidinia Mohammad Ashouri Alireza 《Arabian Journal of Geosciences》2015,8(4):2153-2168
Arabian Journal of Geosciences - In order to reconstruct sea surface water productivity and sea floor oxygenation during late Campanian-Maastrichtian, planktonic and benthic foraminiferal... 相似文献
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Amin Naboureh Mohammad Hossein Rezaei Moghaddam Bakhtiar Feizizadeh Thomas Blaschke 《Arabian Journal of Geosciences》2017,10(12):259
The present paper is an attempt to integrate a semi-automated object-based image analysis (OBIA) classification framework and a cellular automata-Markov model to study land use/land cover (LULC) changes. Land use maps for the Sarab plain in Iran for the years 2000, 2006, and 2014 were created from Landsat satellite data, by applying an OBIA classification using the normalized difference vegetation index, salinity index, moisture stress index, soil-adjusted vegetation index, and elevation and slope indicators. The classifications yielded overall accuracies of 91, 93, and 94% for 2000, 2006, and 2014, respectively. Finally, using the transition matrix, the spatial distribution of land use was simulated for 2020. The results of the study revealed that the number of orchards with irrigated agriculture and dry-farm agriculture in the Sarab plain is increasing, while the amount of bare land is decreasing. The results of this research are of great importance for regional authorities and decision makers in strategic land use planning. 相似文献
35.
Mohammad Abdelfattah Sarhan 《Arabian Journal of Geosciences》2017,10(18):399
Mapping based on the interpreted seismic data covering the Abu Gharadig Basin in the northern Western Desert has revealed that the deposition of the Upper Cretaceous succession was controlled by dextral wrench tectonics. This dextral shear accompanied NW movement of the African Plate relative to Laurasian Plate. Structural depth maps of the Cenomanian Bahariya Formation and the Turonian-Coniacian D and A members of Abu Roash Formation display a clear NE-SW anticline dissected by NW-SE normal faults. This anticline represents one of the en echelon folds characterizing the wrench compressional component. The interpreted normal faults reflect the extensional T-fractures associated with the wrenching tectonics. The interaction between the aforementioned NE-SW anticline with the NW-SE extensional faults further confirms the effect of the Upper Cretaceous dextral wrench tectonic. However, the influence of this wrench tectonics was gradually diminishing from the Cenomanian up to the Coniacian times. The NW-SE compressional stress of the dextral wrench compressional component during the Cenomanian up to Coniacian age was greater in NW direction than the SE direction. Three mapped structural closures which are predicted to be potential hydrocarbon traps belonging to the Bahariya Formation and Abu Roash D Member, and are recommended to be drilled in the study area, with potential reservoirs. The regularity of the en echelon array of both anticlines and normal faults within the wrench zones suggests additional closures may be located elsewhere beside the study area. 相似文献
36.
Mohammad Rezwanul Islam Syeda Fahliza Begum Yasushi Yamaguchi Katsuro Ogawa 《水文研究》1999,13(17):2907-2923
Every year the Ganges and Brahmaputra rivers in Bangladesh transport 316 and 721 million tonnes of sediment, respectively. These high loads of suspended sediment reflect the very high rate of denudation in their drainage basins. The average mechanical denudation rate for the Ganges and Brahmaputra basins together is 365 mm 103 yr−1. However, the rate is higher in the Brahmaputra Basin than that in the Ganges Basin. Several factors, including mean trunk channel gradient, relief ratio, runoff, basin lithology and recurring earthquakes are responsible for these high denudation rates. Of the total suspended sediment load (i.e. 1037 million tonnes) transported by these rivers, only 525 million tonnes (c. 51% of the total load) are delivered to the coastal area of Bangladesh and the remaining 512 million tonnes are deposited within the lower basin, offsetting the subsidence. Of the deposited load, about 289 million tonnes (about 28% of the total load) are deposited on the floodplains of these rivers. The remaining 223 million tonnes (about 21% of the total load) are deposited within the river channels, resulting in aggradation of the channel bed at an average rate of about 3·9 cm yr−1. Although the Brahmaputra transports a higher sediment load than the Ganges, the channel bed aggradation rate is much higher for the Ganges. This study also documents a wide range of interannual, seasonal and daily variation in suspended sediment transport and water discharge. Interannual variation in sediment deposition within the basin is also suggested. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
37.
Faisal Alonaizi Roman Pevzner Andrej Bóna Mohammad Alshamry Eva Caspari Boris Gurevich 《Geophysical Prospecting》2014,62(2):197-209
Time‐lapse seismic analysis is utilized in CO2 geosequestration to verify the CO2 containment within a reservoir. A major risk associated with geosequestration is a possible leakage of CO2 from the storage formation into overlaying formations. To mitigate this risk, the deployment of carbon capture and storage projects requires fast and reliable detection of relatively small volumes of CO2 outside the storage formation. To do this, it is necessary to predict typical seepage scenarios and improve subsurface seepage detection methods. In this work we present a technique for CO2 monitoring based on the detection of diffracted waves in time‐lapse seismic data. In the case of CO2 seepage, the migrating plume might form small secondary accumulations that would produce diffracted, rather than reflected waves. From time‐lapse data analysis, we are able to separate the diffracted waves from the predominant reflections in order to image the small CO2 plumes. To explore possibilities to detect relatively small amounts of CO2, we performed synthetic time‐lapse seismic modelling based on the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) Otway project data. The detection method is based on defining the CO2 location by measuring the coherency of the signal along diffraction offset‐traveltime curves. The technique is applied to a time‐lapse stacked section using a stacking velocity to construct offset‐traveltime curves. Given the amount of noise found in the surface seismic data, the predicted minimum detectable amount of CO2 is 1000–2000 tonnes. This method was also applied to real data obtained from a time‐lapse seismic physical model. The use of diffractions rather than reflections for monitoring small amounts of CO2 can enhance the capability of subsurface monitoring in CO2 geosequestration projects. 相似文献
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39.
Landslides - The accurate prediction of landslide tsunami amplitudes has been a challenging task given large uncertainties associated with landslide parameters and often the lack of enough... 相似文献
40.
Landslides - Natural soils often exhibit an anisotropic fabric pattern as a result of soil deposition, weathering, or filling. This paper aims to investigate the effect of soil interdependent... 相似文献