Identification of spatial and spatiotemporal precipitation variations plays an important role in different hydrological applications such as missing data estimation. In this paper, the results of Bayesian maximum entropy (BME) and ordinary kriging (OK) are compared for modeling spatial and spatiotemporal variations of annual precipitation with and without incorporating elevation variations. The study area of this research is Namak Lake watershed located in the central part of Iran with an area of approximately 90,000 km2. The BME and OK methods have been used to model the spatial and spatiotemporal variations of precipitation in this watershed, and their performances have been evaluated using cross-validation statistics. The results of the case study have shown the superiority of BME over OK in both spatial and spatiotemporal modes. The results have shown that BME estimates are less biased and more accurate than OK. The improvements in the BME estimates are mostly related to incorporating hard and soft data in the estimation process, which resulted in more detailed and reliable results. Estimation error variance for BME results is less than OK estimations in the study area in both spatial and spatiotemporal modes. 相似文献
Geomagnetism and Aeronomy - In this study, a hypothesis is proposed about the possible effect of Geomagnetic field (GMF) on the charge structure of a thundercloud based on Lorentz force equation... 相似文献
Iron oxide–apatite (IOA) deposits, often referred to as Kiruna-type iron ore deposits, are known to have formed from the Proterozoic
to the Tertiary. They are commonly associated with calc–alkaline volcanic rocks and regional- to deposit-scale metasomatic
alteration. In the Bafq District in east Central Iran, economic iron oxide–apatite deposits occur within felsic volcanic tuffs
and volcanosedimentary sequences of Early Cambrian age. In order to constrain the age of formation of these ores and their
relationship with the Early Cambrian magmatic event, we have determined the U–Pb apatite age for five occurrences in the Bafq
District. In a 206Pb/238U vs. 207Pb/235U diagram, apatite free of or poor in inclusions of other minerals plots along the Concordia between 539 and 527 Ma with four
out of five samples from one deposit clustering at the upper end of this range. For this deposit, we interpret this cluster
to represent the age of apatite formation, whereas the spread towards younger ages may reflect either minor Pb loss or several
events of IOA formation. Apatite with inclusions of monazite (±xenotime) yields disturbed systems with inclusions having developed
after formation of the iron ore–apatite deposits, possibly as late as 130–140 Ma ago. Obtained apatite ages confirms that
(IOA) and the apatite-rich rocks (apatites) of the Bafq district formed coevally with the Early Cambrian magmatic (-metasomatic)
events. 相似文献
In this study, the effect of downstream lakes or ponds on dam break flow was investigated. To do this, a robust finite volume method with Harten-Lax-van Leer contact surface Riemann’s solver technique for flux evaluation has been used. For space discretization, a triangular mesh grid was used and a complete software with mesh generator was developed. A reservoir with a long downstream channel was assumed, and many scenarios such as a single lake with various lengths, widths and positions along the channel and multiple consecutive lakes as symmetric and non-symmetric with respect to the channel centerline were considered. The numerical modeling of dam break flow along the channel showed that the downstream lake can decrease the speed and depth of the dam break wave front and the amount of this wave attenuation was very dependent on the storage volume of the lake and vortexes which were established in the lake.
Increasing demand for fresh water extraction in the semi-arid regions necessitates the exploration of groundwater spring potential areas notwithstanding the importance of both conservation and management aspects for planning development. Potential map of groundwater springs reduces the costs of horizontal well drilling that provides useful tool for engineers to locate probable region for groundwater existence. The objective of this study is to establish a model of the potential map of groundwater spring occurrences. A statistical and probabilistic Logistic Regression (LR) model was developed in association with the specified spring location and effective occurrence factors. The most statistically significant effective factors on spring occurrences were selected to zone groundwater spring potential areas. The proposed model was evaluated statistically. Results showed a satisfactory prediction for the proposed model. The outcome of this study facilitates the low-cost utilization of groundwater resources when policy makers need strategic development planning. 相似文献
The Sorkhe‐Dizaj iron oxide–apatite deposit in the Cenozoic Alborz‐Azarbaijan magmatic belt, NW Iran, is hosted mainly by a Late Eocene to Oligocene quartz‐monzonitic body, and subordinately in the Eocene volcanic and volcanoclastic sequences. The Sorkhe‐Dizaj intrusive body is an I‐type granitoid of the calc‐alkaline series. Mineralization is associated with actinolization, K‐feldspar, sericitic, propylitic, and tourmaline alteration types. The orebodies are massive, banded, stockwork, and breccia in shape and occur mainly along the fault zones within the quartz‐monzonitic intrusion, volcanic, and volcanoclastic rocks. Ore minerals dominantly comprise magnetite, apatite, and monazite, as well as minor amounts of chalcopyrite, bornite, and pyrite. Four major paragenetic stages are discriminated in the mineralization including early, oxide, sulfide, and late stage. The Sorkhe‐Dizaj deposit is similar in the aspects of host rock lithology, alteration, and mineralogy to the Kiruna‐type deposits associated with minor Cu sulfide minerals. Spatial and temporal association of the mineralization with the Late Eocene–Early Oligocene quartz‐monzonite intrusive body suggests that the ore fluid was probably related to magmatic activity. 相似文献
Attractiveness of the open urban spaces, such as plazas or squares, depends on the visitor’s thermal comfort. In this respect, it is important to assess the environment of such open space along with the demographic factors of the visitors. This study used the soft-computing method of adaptive neuro fuzzy inference system (ANFIS) to investigate the thermal comfort of visitors at a public square in Iran during hot and cold weather conditions. The ANFIS process for variable selection was implemented in order to detect the predominant variables affecting the individual’s comfortable feeling. Model’s training and testing data were collected through the field measurement and survey during hot and cold times of the year. We used 18 input parameters, representative of demographic and environmental factors, to compute visitor’s thermal sensation, comfort feeling, and 4 common indices, namely the mean radiant temperature (Tmrt), mean physiological equivalent temperature (PET), standard effective temperature (SET) and predicted mean vote (PMV). The results indicated that among the examined factors, the air temperature (Ta) is the most influential parameter and best predictor of accuracy for the individual’s comfort feeling at the studied urban square. The results show that Ta can best predict the common indices of outdoor comfort, namely the PMV, PET, SET, thermal sensation, Tmrt, and comfortable felling compared to other parameters with the least error of 1.94, 18.87, 13.67, 0.91, 7.80, and 0.34 %, respectively. Some of the main advantages of the ANFIS scheme are that it is adaptable to the optimization and adaptive methods, and is computationally efficient. 相似文献