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11.
Streamflow drought severity analysis by percent of normal index (PNI) in northwest Iran 总被引：1，自引：0，他引：1
Jaefar Nikbakht Hossein Tabari P. Hosseinzadeh Talaee 《Theoretical and Applied Climatology》2013,112(3-4):565-573
The streamflow drought is the most important type of drought due to the high dependence of many activities on surface water resources. The streamflow drought severity was identified by the percent of normal index (PNI) in the western basins of the Lake Urmia located in northwest Iran. The streamflow records were obtained from 14 hydrometric stations for the period October 1975–September 2009. The temporal trends of the streamflow drought severity were detected by the parametric Student’s t test and the nonparametric Mann–Kendall and Sen’s tests. The worst streamflow droughts at almost all the stations occurred in 1999–2000 and 2000–2001. The streamflow drought severity based on the PNI increased during the last 34 years. The results also indicated that the temporal dependency of time series had a dominant role in detecting trend by the parametric Student’s t test. 相似文献
12.
The presence of heavy metal concentrations was examined in natural sediments from four sites along the Jajrood river in northeast
of Tehran, the capital of Iran. Besides determination of elemental concentrations (Pb, Cu, Zn, Cd, Ni and Cr), X-ray fluorescence
and X-ray diffraction tests were carried out to determine other chemical components in these adsorbents. Also the ability
of sediments to adsorb these heavy metal ions from aqueous solutions was investigated. Results show that the extent of adsorption
increases with increase in adsorbent concentration. The amount of adsorbed Pb, Cu and Zn in sediments was much greater than
that of the other metals, and Cr was adsorbed much less than others. The adsorbabilities of sediments to heavy metals increased
in the order of Pb > Cu > Zn > Cd > Ni > Cr. Based on the adsorption data, equilibrium isotherms were determined at selected
areas to characterize the adsorption process. The adsorption data followed Freundlich and Langmuir isotherms in most cases.
Correlation and cluster analysis was performed on heavy metals adsorption and sediment components at each site to evaluate
main adsorbing compounds in sediments for each metal. Results demonstrated that heavy metals sorption is mostly related to
load of organic matter in the Jajrood river sediments. 相似文献
13.
Recent trends of mean maximum and minimum air temperatures in the western half of Iran 总被引：3，自引：0，他引：3
Hossein Tabari Parisa Hosseinzadeh Talaee 《Meteorology and Atmospheric Physics》2011,111(3-4):121-131
In this study, the trends of the annual, seasonal and monthly maximum (T max) and minimum (T min) air temperatures time series were investigated for 20 stations in the western half of Iran during 1966?C2005. Three statistical tests including Mann?CKendall, Sen??s slope estimator and linear regression were used for the analysis. The annual T max and T min series showed a positive trend in 85% of the stations and a negative trend in 15% of the stations in the study region. The highest increase of T max and T min values were obtained over Kermanshah and Ahwaz at the rates of (+)0.597°C/decade and (+)0.911°C/decade, respectively. On the seasonal scale, the strongest increasing trends were identified in T max and T min data in summer. The highest numbers of stations with positive significant trends occurred in the monthly T max and T min series in August. In contrast, the lowest numbers of stations with significant positive trends were observed between November and March. Overall, the results showed similar increasing trends for the study variables, although T min generally increased at a higher rate than T max in the study period. 相似文献
14.
Iranian rainfall series analysis by means of nonparametric tests 总被引：1，自引：0，他引：1
P. Hosseinzadeh Talaee 《Theoretical and Applied Climatology》2014,116(3-4):597-607
The study of the trends and fluctuations in rainfall has received a great deal of attention, since changes in rainfall patterns may lead to floods or droughts. The objective of this study was to analyze the annual, seasonal, and monthly rainfall time series at seven rain gauge stations in the west of Iran for a 40-year period (from October 1969 to September 2009). The homogeneity of the rainfall data sets at the rain gauge stations was checked by using the cumulative deviations test. Three nonparametric tests, namely Kendall, Spearman, and Mann–Kendall, at the 95 % confidence level were used for the trend analysis and the Theil–Sen estimator was applied for determining the magnitudes of the trends. According to the homogeneity analysis, all of the rainfall series except the September series at Vasaj station were found to be homogeneous. The obtained results showed an insignificant trend in the annual and seasonal rainfall series at the majority of the considered stations. Moreover, only three significant trends were observed at the February rainfall of Aghajanbolaghi station, the November series of Vasaj station, and the March rainfall series of Khomigan station. The findings of this study on the temporal trends of rainfall can be implemented to improve the water resources strategies in the study region. 相似文献
15.
Parisa Hosseinzadeh Talaee 《Meteorology and Atmospheric Physics》2014,126(1-2):65-70
Reference evapotranspiration (ETo) is significant for water resources planning and environmental studies. Many equations have been developed for ETo estimation in various geographic and climatic conditions, of which, the Penman–Monteith FAO 56 (PMF-56) equation was accepted as reference method. A major complication in estimating ETo by the PMF-56 model is the requirement for meteorological data that may not be readily available from typical weather stations in many areas of the globe. This restriction necessitates use of simpler models which require less input data. In this study, the original and five modified versions of the Hargreaves equation that require only temperature and rainfall were evaluated in humid, semi-humid, semi-arid and arid climates in Iran. The results showed that the original and modified versions of the Hargreaves equation had the poorest performance in semi-humid climate and the best performance in windy humid environment. Further, the ETo estimations with the Hargreaves equations having rainfall parameter were poor as compared to those from the PMF-56 method under majority of the climatic situations studied. 相似文献
16.
China Ocean Engineering - Multiple reflections of the waves between structure and wavemaker in hydraulic flumes could change the frequency content of the desired incident wave or result in... 相似文献
17.
H. Borgheipour F. Hosseinzadeh Lotfi Z. Moghaddas 《International Journal of Environmental Science and Technology》2017,14(8):1697-1712
Sugar plants are one of the most energy-consuming industries in Iran; thus, the implementation of measures to improve energy efficiency seems necessary for such industries. This paper investigated sugar plants’ efficiency in different stages for implementation process of energy efficiency measures focusing on determining some relations for benchmarking and reaching efficient status. In doing so, the process of implementation of energy efficiency improvement measures is planned on the basis of experts’ opinions. Also, for deriving the efficiency of each plant in each of the stages of implementation of measures and the aggregate efficiency of them a multi-stage data envelopment analysis model is formulated. The obtained results from average efficiency indicated that the under evaluation population in the first, second, third, and fifth stages have a good performance and in the fourth-stage managers could not perform successfully. Also, the results of determining some relations for benchmarking showed that to what extent each of the outputs of each stage of the implementation process of energy efficiency measures in the sugar plants should be changed in order to achieve efficient conditions. The distance between the current output and the desirable output indicates to what extent manager has been successful in operation, studies of the rate of change of each of the outputs to achieve the efficient conditions are of the utmost importance in developing suitable strategies. 相似文献
18.
The mineralogy of copper-bearing skarn to the east of the Sungun-Chay river, East-Azarbaidjan, Iran 总被引：2，自引：0，他引：2
A calcic copper-bearing skarn zone in East-Azarbaidjan, NW of Iran is located to the east of the Sungun-Chay river. Skarn-type metasomatic alteration and mineralization occurs along the contact between Upper Cretaceous impure carbonates and an Oligo-Miocene Cu-bearing granitoid stock. Both endoskarn and exoskarn are developed along the contact. Exoskarn is the principal skarn zone enclosed by a marmorized and skarnoid–hornfelsic zone. The skarnification process occurred two stages: (1) prograde and (2) retrograde. The prograde stage is temporally and spatially divided into two sub-stages: (a) metamorphic–bimetasomatic (sub-stage I) and (b) prograde metasomatic (sub-stage II). Sub-stage I began immediately after the intrusion of the pluton into the enclosing impure carbonates. Sub-stage II commenced with segregation and evolution of a fluid phase in the pluton and its invasion into fractures and micro-fractures of the marmorized and skarnoid–hornfelsic rocks developed during sub-stage I. The introduction of considerable amounts of Fe, Si and Mg led to the development of substantial amounts of medium- to coarse-grained anhydrous calc-silicates. From texture and mineralogy the retrograde metasomatic stage can be divided into two discrete sub-stages: (a) early (sub-stage III) and (b) late (sub-stage IV). During sub-stage III, the previously formed skarn zones were affected by intense multiple hydro-fracturing phases in the Cu-bearing stock. In addition to Fe, Si and Mg, substantial amounts of Cu, Pb, Zn, along with volatile components such as H2S and CO2 were added to the skarn system. Consequently considerable amounts of hydrous calc-silicates (epidote, tremolite–actinolite), sulfides (pyrite, chalcopyrite, galena, sphalerite, bornite), oxides (magnetite, hematite) and carbonates (calcite, ankerite) replaced the anhydrous calc-silicates. Sub-stage IV was concurrent with the incursion of relatively low temperature, more highly oxidizing fluids into skarn system, bringing about partial alteration of the early-formed calc-silicates and developing a series of very fine-grained aggregates of chlorite, clay, hematite and calcite. 相似文献
19.
Sajjad Maghfouri Mohammad Reza Hosseinzadeh Abdorrahman Rajabi Flavien Choulet 《地学前缘(英文版)》2018,9(1):249-272
The numerous non-sulfide zinc ore deposits were the historical basis for the development of zinc mining in Iran.They include the Mehdiabad,Irankouh and Angouran world-class deposits,as well as the Zarigan and Haft-har deposits.These deposits were formed by supergene oxidation of primary sulfide minerals during the complex interplay of tectonic uplift,karst development,changes in the level of the water table,and weathering.Zn(Pb)carbonates,Zn-hydrosilicates and associated hydrated phases directly replace the primary ore bodies or fill cavities along fractures related to uplift tectonics.Direct replacement of primary sulfides is accompanied by distal precipitation of zinc non-sulfide minerals in cavities or internal sediments filling.The mineralogy of the non-sulfide mineralization in all six deposits is generally complex and consists of smithsonite,hydrozincite,and hemimorphite as the main economic minerals,accompanied by iron and manganese oxy-hydroxides and residual clays.Commonly,non-sulfide minerals in these deposits consist of two types of ore:red zinc ore(RZO),rich in Zn,Fe,Pb-(As)and white zinc ore(WZO),typically with very high zinc grades but low concentrations of iron and lead.Typical minerals of the RZO are Fe-oxyhydroxides,goethite,hematite,hemimorphite,smithsonite and/or hydrozincite and cerussite.Common minerals of the WZO are smithsonite or hydrozincite and only minor amounts of Fe-oxyhydroxides and hemimorphite. 相似文献
20.
Hossein Tabari P. Hosseinzadeh Talaee Hirad Abghari 《Meteorology and Atmospheric Physics》2012,116(3-4):147-154
Estimation of pan evaporation (E pan) using black-box models has received a great deal of attention in developing countries where measurements of E pan are spatially and temporally limited. Multilayer perceptron (MLP) and coactive neuro-fuzzy inference system (CANFIS) models were used to predict daily E pan for a semi-arid region of Iran. Six MLP and CANFIS models comprising various combinations of daily meteorological parameters were developed. The performances of the models were tested using correlation coefficient (r), root mean square error (RMSE), mean absolute error (MAE) and percentage error of estimate (PE). It was found that the MLP6 model with the Momentum learning algorithm and the Tanh activation function, which requires all input parameters, presented the most accurate E pan predictions (r?=?0.97, RMSE?=?0.81?mm?day?1, MAE?=?0.63?mm?day?1 and PE?=?0.58?%). The results also showed that the most accurate E pan predictions with a CANFIS model can be achieved with the Takagi–Sugeno–Kang (TSK) fuzzy model and the Gaussian membership function. Overall performances revealed that the MLP method was better suited than CANFIS method for modeling the E pan process. 相似文献