فهرست مطالب

Environmental Resources Research - Volume:5 Issue: 2, Winter - Spring 2017

Journal of Environmental Resources Research
Volume:5 Issue: 2, Winter - Spring 2017

  • تاریخ انتشار: 1396/10/28
  • تعداد عناوین: 7
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  • Fakhrieh Shirood Mirzaie *, Renaud Claud B., Rasoul Ghorbani Pages 111-122
    Various biological characteristics were compared between autumn and spring runs of Caspiomyzon wagneri migrating into the Shirood River, in an attempt to determine whether these were reproductively isolated. Two spawning runs of the same lamprey species in a single river are apparently unique to the Shirood. The autumn sample collected between 21 October and 1 November 2009 comprised 15 adults and the spring sample collected between 22 March and 18 April 2009 comprised 38 adults. While spawning was not witnessed, the significantly shorter mean total length of at least 40 cm in both males and females, and the significantly higher gonadosomatic index in females of the autumn run versus the spring run suggest that the former is closer to spawning than the latter. If one assumes a single spawning population per year in the river, the report by Nazari and Abdoli (2010) of recently spent individuals of Caspian lamprey collected in the Shirood River during April, would therefore imply that the spawning period is remarkably protracted. In order to test this hypothesis, the spawning sites need to be searched for higher upstream over the entire year, particularly in areas where suitable spawning substrate of gravel and sand occurs.
    Keywords: Upstream migration, Caspiomyzon wagneri, Shirood River, Caspian Sea
  • Khabat Khosravi *, Mahmoud Habib Nejad Roshan, Atta Safari Pages 124-134
    This study aimed to evaluate the temporal change and accuracy of interpolation techniques used for spatial zonation of two groundwater quantity parameters including water table and depth to water table over 11 years. The study was conducted based on the data collected from piezometric wells of Sari-Neka Plain in Mazandaran Province, Iran. The investigated methods included a set of geostatistical approaches involving simple Kriging, ordinary Kriging, Radial Basis Function (RBF), and a deterministic interpolation method called Inverse Distance Weighting (IDW) with powers of 1 and 5. Subsequent to quality control and data normalization, the most appropriate variogram was chosen based on low RSS and high r2 while the most suitable interpolation technique was determined regarding the cross validation, Mean Absolute Error (MAE), and Mean Bias Error (MBE). The results demonstrated that Simple Kriging was the most suitable method for zoning the depth to groundwater over the years 2001, 2006, and 2012. Meanwhile, the most suitable methods for zoning the water table included IDW with a power of 1for the year 2001, RBF for the year 2006, and IDW with a power of 5 for the year 2012. The important finding was that the interpolation methods showed a lower error for estimating water table than estimating depth to groundwater. This study also revealed a drop in water table in the study area over the 11 years’ period. Meanwhile, new water table classes have been added and extended between the years 2006 and 2012 that had not existed five years earlier. The highest water table losses were observed in three points at 13m depth to water table in the middle and northern parts of the study area.
    Keywords: Interpolation Methods, Variogram, Geostatistics, Groundwater, MAE, MBE
  • Abolfazl Ranjbar *, Ehsan Zandi Esfahan Pages 135-142
    Smirnovia iranica, a native valuable woody species from Fabaceae, is an adaptable plant from the central sandy areas of Iran. Changes in chlorophyll fluorescence and photosynthetic pigment characteristics were analysed in the course of dust accumulation during April (Ap); April and May (AM); and April, May and June (AMJ) periods, respectively. The results obtained from the analysis of variance indicated that there was a significant difference among different dust-loading periods of S. iranica in terms of the characteristics mentioned. Extending dust accumulation resulted in a significant reduction in the Fv /Fm ratio in AM and AMJ. A significant effect of dust deposition on thermal dissipation of the light energy (D) value was observed in AM and reached the highest value in AMJ. In all evaluated plants, during the course of dust accumulation, there was a decrease in the photochemical efficiency of photosystem II (ΦPSII), and from AM. A similar influence of the extending dust accumulation periods on ΦPSII was observed for the electron transport rate (ETR). Our results proved that dust deposition decreased overall plant performance through its severe effect on pigment content and resulted in a significant inhibition of PSII efficiency throughout this study period.
    Keywords: Dust, Electron transport rate, Photosynthetic apparatus, Thermal dissipation, Pigment
  • Jalal Salem *, Mojtaba Mojaverian Pages 143-152
    Urban population growth (non-agricultural population) in developing countries has challenged the food security of urban households. The precise demographic definition of urbanization is the increasing share of a nation's population living in urban areas (and thus a declining share living in rural areas). Mostly, urbanization is the result of net rural to urban migration. We investigated the food security among urban households and the effects and various factors involved for the period of 1983 to 2012. Results showed that during this period the food security of urban households had an increasing trend. Despite the enhancement of food security among urban households, 5.6 percent of the urban populations received less than necessary kilojoules level in 2012, role factors were evaluated as well using time series pattern after estimation of urban household's aggregate food security index (AHFSI). Results showed that effect lag variable of aggregate food security index changes on growth of aggregate food security index in the next year will be significantly negative (at 1% level). These results exhibited that with increase in one-unit growth of food security index in one year, it would decrease by 0.008 units the next year. Every one percent increase of people receiving less than standard energy level will decrease the growth of food security index by 0.009 units. This finding is significant at 10 percent level. Nevertheless, the 1st to 3rd five-year development plans showed more growths on food security indices in comparison with the 4th development plan. Furthermore, the second development plan showed the maximum increase of food security index in comparison with the 4th development plan. Based on the results, the constant and steadily increasing trend of the food security index should be considered as a priority in the future development plans.
    Keywords: Food security, Non- agricultural population, Development plans, Iran
  • Khadigeh Javan *, Mohammad Reza Azizzadeh Pages 153-168
    Satellite rainfall estimate systems can produce data for areas for which other sources are unavailable. Without referring to ground measurements, satellite-based estimates cannot be used directly before bias correction. This study aims to evaluate the performance of the TRMM-3B43 V7 rainfall products in the Northwest of Iran. The evaluation was carried out using monthly data obtained from 21 meteorological stations during 1998–2015. The monthly and annual spatial distributions of the Pearson correlation coefficient between the station and satellite-based observations as well as the statistical error measure were calculated. The results revealed that the correlations between TRMM 3B43 and rain gauge data were high (R> 0.80) in October and small (R 30 mm) and in December to May (>20 mm). On the contrary, an underestimation was found in the Southwest regions where summer season (June, July & August) is generally characterized by small anomalies in terms of R values. Generally, the satellite products applied in this study underestimate higher rainfall values while showing overestimation for lower rainfall records. The measure of Root Mean Square Error (RMSE) showed that a large spatial variability takes place in September, October and November in most of the stations, particularly when rainfall records is less than 50 mm. Meanwhile, the lowest variability occurred in June, July and August with a slight increase in the Northeast. Our findings imply that satellite products have poor performance for estimating higher rainfalls in the Northwest of Iran on a monthly scale.
    Keywords: TRMM-3B43 V7, Rainfall variability, Northwest of Iran
  • Meysam Alizamir *, Mehdi Azhdary Moghadam, Arman Hashemi Monfared, Ali Akbar Shamsipour Pages 169-182
    Assessment of the impacts of climate change on water resources has been obtained significant attentions in the past decade. This paper assesses the climate change impacts on precipitation in the Minab basin, in the Hormozgan province in Iran. Two monthly precipitation downscaling methods were proposed based on multi-layer perceptron (MLP) and radial basis function (RBF) neural networks. The downscaling models were calibrated and validated using the large scale climatic parameters (predictors) derived from National Center for Environmental Prediction (NCEP)/ National Centre for Atmospheric Research (NCAR) reanalysis data set for downscaling monthly precipitation in the Minab basin in Iran. Pearson correlation was employed to choose the predictors among the NCEP/ NCAR reanalysis data set and final predictor combination for each station is assigned. The results of the downscaling models revealed that the MLP model produced more accurate and consistent results by downscaling the large scale climatic parameters compared to the RBF model. The proposed model can be reliably utilized for developing future projections of precipitation using the general circulation models outputs which can be employed also as the inputs in hydrological models.
    Keywords: Climate Change, Statistical Downscaling, Artificial Neural Network, Multilayer Perceptron, Radial Basis Function
  • Maryam Saeed Sabaee *, Abdolrassoul Salmanmahiny, Seyed Mohammad Shahraeini, Seyed Hamed Mirkarimi, Norodin Dabiri Pages 184-196
    One of the most important and appealing subjects discussed and applied in many geographical studies is compactness. This is a geometrical notion and has applications far beyond the scope of its definition. Besides the importance of measuring compactness in a single object, its study is significant in real-world applications, where the integration of items or objects in conjunction with each other is considered. Regionalization is the term commonly used for this integrative perspective. Although there are several methods to quantify compactness, this study tries to illustrate the simple way for its calculation. Hence, this study is devised to apply with some modifications one of the methods that has been suggested for calculating single object compactness in regionalization domain. We attempt to propose a clear definition and to evaluate the computer implementation of the compactness in a land-use planning study. The ant colony algorithm as a heuristic approach was applied to measure compactness in an innovative manner and to incorporate this concept into a land-use planning case. Results show that this method can be useful in achieving compactness in land-use planning.
    Keywords: Compactness, Regionalization, Land-use planning, Ant colony