Showing 41 results for Alizadeh
N S, A Alizadeh, S Mosa Nejad,
Volume 13, Issue 48 (7-2009)
Abstract
A comprehensive study is underway now to determine the predicting factors of rice blast and its loss assessment in Guilan province. In a preliminary study, the effect of climatic factors on spores population and forecasting the disease were considered. So, during cultivation season of 2006 and 2007, some fields were chosen five kilometers away from weather stations in three regions of Guilan, including, Rasht, Lahijan and Anzali, and the daily spore population was measured on slides. Climatic data including precipitation (mm), maximum and minimum daily temperature, maximum and minimum daily humidity and sunny hours were obtained from weather stations. Then the relation between spore population and weather data was analyzed, and the most important climatic factors affecting spore population and predicting of rice blast were determined. It was concluded that climatic factors such as precipitation (mm), maximum daily temperature, minimum daily humidity and sunny hours are the most important factors for predicting rice blast in Guilan province. Spore population was positively correlated with precipitation, increase of daily minimum humidity, decrease of daily maximum temperature and decrease of sunny hours. The blast disease occurred in the fields during next 7 to10 days.
H.a Alizadeh , F Abbasi , A Liaghat ,
Volume 14, Issue 51 (spring 2010)
Abstract
The application of N fertilizers with surface irrigation stream (surface N fertigation( is a key approach for fertilizer management. The main objective of this study was to investigate furrow fertigation management effects on distribution uniformity and runoff losses of nitrate in field scale. A field corn experiment was carried out with a complete randomized block design having 12 experiments. The field experiments were carried out in free draining furrows having 165 m length and 0.006 m/m slope in Karaj. Required urea fertilizer was applied in four stages: before planting, in seven leaves stage, shooting stage and earring stage. The first stage was accomplished by traditional method and other stages were applied with irrigation water (fertigation). Fertigation timing was respectively 60, 35, and 20 min in the three fertigation stages. Results showed that distribution uniformity of water and fertilizer of low half (DULH) provided high values for all experiments. DULH ranged between 88.0 to 99.0% and 89.7 to 96.0%, respectively for water and fertilizer. Also, distribution uniformity of low quarter (DULQ) ranged between 86.0 to 98.2% and 85.7 to 91.5%, respectively for water and fertilizer. Nitrate losses through surface runoff ranged between 5.7 to 42.0%. Duncan test results for comparison between different experiments showed that there was significant difference (p=0.95) between fertilizer losses at the level of fertilizer injection time of 60 and 35 minutes, but there was no significant difference between levels of 35 and 20 minutes.
Sh. Kiani, Gh. Zadeh Dabagh, M.j Malakouti, A. Alizadeh ,
Volume 14, Issue 51 (spring 2010)
Abstract
Gray mold, caused by Botrytis cinerea, is a serious disease of cut rose flowers (Rosa hybrida L.) in Iran. In order to elucidate the effects of different potassium and calcium levels in nutrient solution on susceptibility of cut rose flowers to gray mold, this experiment was carried out as factorial design in a randomized complete block with four replications at Safi Abad Agricultural Research center in 2008 for one year. In this experiment, rose plants were grown and subjected to three levels of potassium (1.0, 5.0 and 10.0 mM) in combination with two levels of calcium (1.6 and 4.8 mM) under hydroponic condition. Rose flowers from two consecutive harvesting periods were sprayed with the conidial suspension (104 spore/ml) of B. cinerea isolate. At the end of experiment the disease severity was recorded and analyzed. The results indicated that application of 10.0 mM K in the nutrient solution led to increasing rose disease severity to gray mold (30.4 % day-1) compared to 1.0 mM (24.8 % day-1) and 5.0 mM (26.2 % day-1) of K levels (P< 0.01). The increased susceptibility was associated with a decreased concentration of Ca in the rose petals. Correlation analysis revealed that susceptibility of rose flowers to gray mold significantly increased with K to sum cations ratio in the nutrient solution (r = 0.94*). The increase of Ca supply from 1.6 to 4.8 mM resulted in decline of disease severity from 29.6 to 24.6 % day-1 (P< 0.01). Therefore, balanced application of potassium and calcium (5.0 and 4.8 mM, respectively) is recommendable for preventing antagonistic effects between them and reducing of rose gray mold intensity under hydroponic conditions.
L. Parviz , M. Kholghi, Kh. Valizadeh,
Volume 15, Issue 56 (sumer 2011)
Abstract
The determination of air temperature is important in the energy balance calculation, hydrology and meteorological studies. In this regard, the limited number of meteorological stations is one of the serious problems for air temperature determination on a large spatial scale. The remote sensing technique by covering large areas and using updated satellite images might be appropriate for estimation of this parameter. In this research, the negative correlation between land surface temperature and vegetation index (NDVI) has been used for air temperature estimation through TVX method in which the inference of air temperature is based on the hypothesis that the temperature of the dense vegetation canopy is close to air temperature. For investigation the performance of TVX method, images of MODIS sensor have been applied for the Sefidrod River basin in the years 1381- 1382-1384. The spilt window technique which was developed by Price has been used for land surface temperature calculation. The mean difference between observed and estimated land surface temperature using Price algorithm was about 6.2Co. This error can affect the air temperature values. Because of using NDVI index in TVX method, this method has the sensitivity to the vegetation density, though in the parts with sparse vegetation, the value of error increases. 4 percent variation of air temperature against the 0.05 increasing of maximum NDVI indicates the high performance of TVX method for air temperature estimation in large areas.
V. Sarvi Moghanloo , M. Chorom, H. Motamedi , B. Alizadeh, Sh. Ostan,
Volume 15, Issue 56 (sumer 2011)
Abstract
Soil enzymes are the catalysts for important metabolic process functions including the decomposition of organic inputs and the detoxification of xenobiotics. The aim of this research was to determine the pattern of variation in the activities of dehydrogenase, urease, lipase and phosphatase enzymes, determining the number of hetrotrophic and degrading bacteria and measuring the soil respiration and yield plants during the bioremediation of oil contaminated soils. To this aim, the soil deliberately contaminated with crude oil at a 1 and 2 wt% rate and in four treatments including: plant multiflorum (T1), plant multiflorum with mycorrhiza inoculation (T2), plant multiflorum with oil degrading bacteria inoculation (T3), plant multiflorum with mycorrhiza and oil degrading bacteria inoculation (T4) was employed for bioremediation of oil contaminated soil. The above parameters were determined in five stages during bioremediation and ultimately for the yield of plants at the end of this period .The results showed that the activity of urease and hydrogenase anzymes were increased or decreased parallel to contaminant increase and decrease. In contrast, the activity of lipase anzyme was decreased with contaminant increase and increased with contaminant decrease. Therfore, it can be a good choice for monitoring of bioremediation of contaminated soils. The results showed that the number of degrading and hetrotrophic microorganisms were increased by increasing the amount of contamination and the number of degrading and heterotrophic bacteria were decreased parallel to contaminant decreasing especially in those samples treated with mycorrhiza inoculation. The plant yield and amount of degradation of oil compounds were highest in mycorrhiza plus degrading bacteria treatment.
M. Alizadeh, F. Mirzaii, T. Sohrabi , M. Kkavosi , M. R Yazdani,
Volume 17, Issue 66 (winter 2014)
Abstract
Water management in cracked paddy soils is an important issue in rice cultivation. In order to study organic matter and zeolite effect and their interaction on moisture conditions and hydraulic and physical properties of paddy soils, the organic matter (rice straw) at four levels (0, 8, 16 and 24 tons per hectare), zeolite at four levels (0, 0.5, 1 and 1.5 percent ), and also moisture stages of soil at 5 levels were selected. This experiment was conducted in Rice Research Institute of Iran. Randomized Complete Block Design (RCBD) was used to study the effect of treatments on different subjects. The amount of moisture, bulk density and the distance of soil from the wall of container were measured in a 4-month period. The obtained results showed that the interaction effects of organic matter and zeolite on soil moisture content were statistically significant at one percentage level. Addition of plant residues caused an increase in soil moisture weight and reduction in bulk density compared to the control treatment. It was also found that soil moisture content and bulk density were highly correlated. Bulk density of control treatment ranged from 0.75 to1.7 gr/cm3, while with addition of 1.5 % crop residue the bulk density ranged from 0.7 to 1.3gr/cm3. Overall results show that crop residues are effective in reduction of crack parameters of soil , but zeolite cannot be effective although it causes more maintenance of soil moisture.
N. Alizadeh, M. A. Ghorbani, S. Darbandi,
Volume 19, Issue 71 (spring 2015)
Abstract
Information on suspended sediment variation in times of flood is important in management of water resources, particularly management of basins, and in investigation of the causes of erosion. The relationship between discharge and suspended sediment concentration during floods is not similar and homogeneous for different reasons such as precipitation variety, discharge rate and sources of sediment and production of hysteretic loops. In this study, the instantaneous values of suspended load were simulated using genetic programming and regression methods. By comparing the two models, Genetic programming model was selected as the better one with the mean square error and determination coefficient of 0.8 and 0.5, respectively. Then based on this model, loops of suspended hysteretic load were drawn for the six events recorded in the period of 1387-1383. This resulted in 4 linear and 2 clockwise hysteretic loops for the river suspended sediment. Identifying various hysteretic loops is effective in determination of relative contributions of processes to production and transfer of sediment including amount and intensity of precipitation, flow rate and previous moisture conditions of watershed. The results showed that the clockwise hysteretic loops occurred usually in high precipitation and discharge, and linear hysteretic loops in spring because of low intensity precipitation.
M. Marzi Nohadani, B. Mostafazadeh-Fard, S. F. Mousavi, M. R. Yazdani, M. R. Alizadeh,
Volume 19, Issue 72 (summer 2015)
Abstract
The common method of puddling is using a conventional tiller which requires long time of soil operations.In this study, the effects of tillage equipment on moisture characteristic curve of a paddy soil were investigated. The treatments included tillage equipment (T1: conventional tiller, T2: rotary puddler, T3: cone puddler, T4: tractor mounted rotivator) and number of puddlings (P1: puddling once, P2: puddling twice, P3: three times'puddling and P4: four times'puddling). The results showed that at saturation point, tractor mounted rotivator presented the highest moisture content. At field capacity and permanent wilting point, the cone puddler showed the highest moisture value. The two newly made units held more moisture and saved water. In different tillage equipment, increasing the number of puddling reduced soil moisture. Available moisture in the soil without tillage (control) was less than in soils under rotary puddler and cone puddler.
R. Valizadeh Yonjalli, F. Mirzaei Aghjehgheshlagh, A. Ghorbani,
Volume 19, Issue 73 (fall 2015)
Abstract
This study was conducted to determine some mineral content concentration in soil and plant of three elevation classes (1500, 2200 and 3000m) and two phenological stages of flowering and seedling start in north-facing slopes of Sabalan rangelands. Soil samples from the depth of 20cm and plant samples using 1×1m plots with 10 replications were collected. After sample preparation, the concentrations of minerals such as calcium, phosphorous, sodium, potassium, ion, copper, zinc and magnesium were determined using spectrophotometer and flame photometer. Data was analyzed by SAS9.1 software using Completely Randomized Design with a Generalized Linear Model procedure. Results showed that elevation had a significant effect on Ca, Fe, Cu, Zn and Mn of soil and P, Na, K, Mg and Mn of plants in the study areas (P&le0.05). Growing stages had a significant effect on all elements of plants except Ca (P&le0.05). Moreover, results showed that in three elevation classes the high demand minerals’ concentration was higher at the starting seedling stage in comparison with the flowering stage. In contrast, the low demand minerals’ concentration in three elevation sites was higher in the flowering stage in comparison with seedling stage. Interaction effect of elevation and growing stage was also significant in relation to all elements except Ca (P&le0.05).
A Heidari, H. Haji Agha Alizadeh, A. R. Yazdanpanah, J. Amiri Parian,
Volume 20, Issue 78 (Winter 2017)
Abstract
Traditionally, most corn field in Hamedan Province is prepared for planting by moldboard plowing followed by a number of secondary tillage operations. In recent years conservation tillage systems have become more popular. This research was conducted in the form of a split plot experimental design with six tillage treatments and three replications. Main tillage methods including: (T1) conventional tillage (moldboard plow + cyclotiller equipped with roller), (T2) combination tiller (chisel plow equipped with roller) (T3) bandary tillage with chisel blades were considered as main plots and two P fertilizer application including: (F1) fertilize broadcasting and (F2) fertilizer bandary placement were considered as sub plots. During growing seasons, soil mechanical resistance (cone index), soil bulk density and water infiltration in soil were measured. At the end of the growing season (harvesting time), corn yield and its components were measured. Results indicated that tillage methods and soil depth had a significant effect on the soil bulk density and cone index. The effect of tillage on water infiltration in soil was significant. The effect of P fertilizer application on corn yield was significant (P≤0/01) and P fertilizer bandary placement with mean corn yield of 10862 kg/ha had higher yield value than the fertilizer broadcasting with mean corn yield of 9965 kg/ha. Although the difference between tillage methods for corn yield was not statistically different, T2 treatment with mean corn yield of 10913 kg/ha had higher yield value than the other two tillage treatments (T1 with mean corn yield of 10106 kg/ha and T3 with mean corn yield of 10222 kg/ha).
M. Khoshravesh, M. Valizadeh,
Volume 21, Issue 2 (Summer 2017)
Abstract
Construction of a dam in the upstream of Tajan basin, as one of the human activities in order to provide drinking water, hydropower, agriculture, flood control or other purposes, can be effective on other sectors such as water resources. The purpose of this study is investigating the impact of Rajaei dam on groundwater resources in Sari-Neka plain during 26 years period (1985-2011) using geostatistical method, parametric and non-parametric tests. The results of statistical tests showed that groundwater table variation during 26 years has experienced insignificant upward trend. Quality factors such as EC, TDS, TH, Cl, SO4, Mg, Na and SAR had significant downward trend at 5% confidence level for Pearson and Kendall test. The Quality changes of groundwater resources in the region had good condition due to construction of dam. The results of spatial analysis for the study area using Kriging interpolation method in the three years for 1985, 1999, 2011 showed that in 1999 (the year of exploitation of the dam) most of the quality factors had reached the highest level from 1985 until the dam operation (1999) and then decreased to 2011. The results of this study showed that, agricultural activities after dam construction, operation of irrigation system and drainage network design of Rajaei dams, have raised the water table in northern part of the region and consequently had a significant impact on the quality of water resources.
K. Roshangar, R. Valizadeh,
Volume 21, Issue 2 (Summer 2017)
Abstract
Hydraulic jump is the most common method of dissipating water’s kinetic energy in downstream of spillways, shoots and valve. In this paper, Support Vector Machine (SVM) method, as a machine learning method, have been used to estimate hydraulic characteristics such as the sequent depth ratio, jump length and energy loss in three different sudden expansions stilling basins, and the rate of influence of input parameters in each jump has been analyzed. In order to evaluate the performance of proposed method, 936 sets of the observed data have been used for training and testing process of three kinds of expanding channel models. Furthermore, a comparison between semi-theoretical approaches and the data obtained from the best SVM models have been carried out. The results confirmed the efficiency of SVM method for estimating the hydraulic jump characteristics and proved that this method performed well in comparison to the semi-theoretical relationships. The obtained results revealed that the superior model for the sequent depth ratio and relative energy dissipation was the model with (Fr1,h1/B) parameters and the superior model for the length of hydraulic jump prediction was the model with (Fr1, h2/h1) parameters.
A. Jamal, A. Parvan, D. Valizadeh,
Volume 23, Issue 4 (Special Issue of Flood and Soil Erosion, Winter 2019)
Abstract
Today, the preparation of flood zoning maps is one of the basic and important issues in the study of development projects in the world; it is considered before any investment by the related organizations. In this paper, flood zoning was performed using the two-dimensional model HEC-RAS and GIS in order to assess the risk of the construction of a railway station near the bank of the Iranshahr River, in a range of 2500 meters. Two-dimensional hydraulic application could create a more accurate flow pattern in comparison to the one-dimensional model used in the previous studies, especially in the flood plain areas. In this paper, due to the important role of the topography of the area in ensuring the accuracy of the calculation, a Digital Elevation Model (DEM) was used with very high precision (about 2 meters), as obtained from aerial photos. The results of this study indicated the onrush of flood, depth and flow velocity in different return periods. Based on the comparison of water surface profiles in the floodplains with the return period of 100 and 25 years, the maximum difference between the water levels was 0.5 m, which seemed to be reasonable by considering the low slope of the studied area. The results of this paper, therefore, showed that the location of the railway station was in medium risk and the outskirt of floodplain.
M. Majedi Asl, S. Valizadeh,
Volume 23, Issue 4 (Special Issue of Flood and Soil Erosion, Winter 2019)
Abstract
Local scour around the foundation of marine and hydraulic structures is one of the most important factors in the instability and destruction of these structures. False prediction of scour depth around bridges has caused financial losses in plasticization and endangered many people's lives. Therefore, an accurate estimation of this complex phenomenon around the bridges is necessary. Also, since the formulas presented by different researchers relate to laboratory conditions, they are less true and less accurate in other situations. Recently, many researchers have tried to introduce new methods and models called soft calculations in predicting this phenomenon. In this research, 146 different laboratory data series (three different laboratory conditions) were analyzed using a backup vector machine to predict scour depth around the bridge head. These data are presented in the form of various combinations of input parameters which, respectively, represent thickness under the slippery layer, Reynolds number, critical velocity, Shields parameter, velocity Shear, average speed, flow depth, the average diameter of the particles and diameter of the bridge. The parameters in two different scenarios (the mode with dimension and mode) were introduced into the SVM network and the results of this machine were compared with those obtained from the experimental formulas and relations presented in this study. The results showed that in the first scenario, the combination of No. 5 with input parameters () and in the second scenario, the combination No. 5 with input parameters () for the test stage were selected as the best model. It was also concluded from the results that the scenario two (the state with dimension) in predicting the scour depth around the vertical single-pillar provided a more accurate estimate than the first scenario (barrier state). At the end, the sensitivity analysis was carried out on the parameters and the parameters D, U*, V were selected, respectively, as the most effective parameters
A. Alizadeh, B. Yaghoubi, S. Shabanlou,
Volume 24, Issue 2 (Summer 2020)
Abstract
In this study, the discharge coefficient of sharp-crested weirs located on circular channels was modeled using the ANFIS and ANFIS-Firefly (ANFIS-FA) algorithm. Also, the Monte Carlo simulations (MCs) were used to enhance the compatibilities of the soft computing models. However, the k-fold cross validation method (k=5) was used to validate the numerical models. According to the input parameters, four models of ANFIS and ANFIS-FA were introduced. Analyzing the numerical results showed that the superior model simulated the discharge coefficient as a function of the Froude number (Fr) and the ratio of flow depth over weir crest to the weir crest height) h/P(. The values of the mean absolute relative error (MARE), root mean square error (RMSE) and correlation coefficient (R) for the superior model were calculated 0.001, 0.002 and 0.999, respectively. However, the maximum error value for this study was less than 2%.
M. Majedi Asl, R. Daneshfaraz, S. Valizadeh,
Volume 24, Issue 2 (Summer 2020)
Abstract
Sand mining from rivers is one of the biggest concerns in the science today. Certain principles and rules for choosing the right place for mining materials and the amount of this mining are missing in the design codes. Therefore, mining of river materials from sites with less potential and near structures has been occasionally seen. In the present study, it has been attempted to reinforce the structure to control the impact of the mining of material, which results in the increased scour by changing the flow pattern around the structure. The experiments were carried out in two simple and armed modes, in sand bed with a grain size of 0.78 mm, with a length of 4.25 meters, inside a canal of 13 meters in length and 1.2 meters in width. The extent of scouring along the longitudinal and transverse directions in different times from the start to the scouring equilibrium was investigated for all substrates under sub-critical flow conditions (range 0.5-0.25). The results showed that the use of a cable-protected method in the upstream pit led to 29.6% reduction in the maximum scour depth at the front and 34% reduction in the back of the pier; also, in the downstream of the pit, it reduced the maximum scour depth by 15% at the front of the pier. Therefore, the cable arrangement used at the piers surface, according to the current research method, resulted in a significant reduction in the depth and extent of scouring in the pier group of the bridge.
H. Alizadeh, A. Hoseini, M. Soltani,
Volume 24, Issue 3 (Fall 2020)
Abstract
The construction of irrigation network and the water transfer from Karkheh Dam to Dashte-Abbas, due to neglecting the groundwater resources has increased groundwater level and waterlogging of the agricultural land in the recent years. The aim of this study was, therefore, to optimize the conjunctive use of surface and groundwater resources in Dashte-Abbas to minimize waterlogging problems and achieve the maximum net income. For this purpose, the behavior of groundwater was simulated using the system dynamics (SD) approach. The conjunctive use of surface and groundwater resources was then optimized using the Vensim multi-criteria optimization method with the objective function of maximizing the net income of the plain. The SD model calibration was done using climatic, hydrological, agricultural, and environmental data from the 2001-2009 time period; then it was validated based on the information from the 2009-2016 period. Evaluation of the developed SD model showed that the model had high accuracy in simulating key variables such as groundwater levels (ME=60cm, R2=97%, RMSE=47cm) and groundwater salinity (RMSE=100μS/cm, R2=74%, and ME=123μS/cm). Furthermore, the results of the optimization model showed that the optimum use of surface and groundwater resources for the agricultural demand was 65% and 35%, respectively. To sum up, it could be concluded that with the optimization of the conjunctive use of surface and groundwater resource, s about 10 MCM of water consumption could be annually saved to irrigate almost 800 ha of the new lands.
F. Alizadeh, A. H. Nasrolahi, M. Saeedinia, M. Sharifipour,
Volume 25, Issue 1 (Spring 2021)
Abstract
In areas with high rainfall distribution, proper irrigation management, including complementary irrigation, is one of the effective strategies to increase crop production. In order to investigate the effect of supplementary irrigation in different growth stages on the yield and water productivity of Autumn rapeseed, an experiment in the form of a complete randomized block design with five irrigation management treatments including rainfed (I1), single irrigation at flowering stage (I2), single Irrigation at pod filling stage (I3), two irrigation at pod filling stage and flowering (I4), three irrigation at flowering, and pod filling and grain Filling stages (I5) was carried out at Lorestan University Research Field. Results showed that there was a significant difference between the effects of different irrigation treatments at 1% level. The lowest grain yield, biological yield and oil yield were obtained in I1 treatment with 44.62%, 50.95% and 53.58% decrease, as compared to I5 treatment. The results also showed that by applying irrigation at pod filling stage, grain yield and oil yield were increased by 13.22% and 20.23%, as compared to I1 treatment. The highest total productivity for the grain yield and oil yield was obtained in I5 treatment with 0.252 and 0.073 kg / m3. In general, due to the fact that drought stress in rapeseed calving stages reduces yield, the higher the number of irrigations in rapeseed calving stages, the more the yield.
H. Ghanbari, J. Mamizadeh, M. Valizadeh,
Volume 25, Issue 3 (Fall 2021)
Abstract
Water hammer is one of the unsteady flows in urban water distribution networks, which has been of great importance due to the damage caused to the pipeline and has always been of interest to researchers. In this study, the phenomenon of water hammer due to the sudden closure of the valve in the downstream end has been investigated in a laboratory and using a numerical model. In the laboratory section of the study, the effect of flow changes with control equipment and without control equipment on the maximum and minimum height of pressure wave head was investigated. The results showed that the proper performance of the surge tower pipe in reducing the maximum pressure wave as well as improving the negative pressures in the system. In a maximum discharge of 35.75 liters per minute, surge tower pipe reduced pressure wave head by a maximum of 70.40%. In a minimum discharge of 7.70 liters per minute, the surge tower pipe reduced the height of maximum pressure by 34.82%. Also, in minimum discharge, surge tower pipe has improved the minimum pressure wave head by more than 78%. AFT Impulse numerical model was used to analyze the water hammer. The results of the numerical model were examined in a benchmark problem using a characteristic method and its validity was confirmed. Simulation of laboratory model with numerical software showed that this software only predicts the first wave properly when water hammer produces negative pressures, but in the next cycles it does not show the depreciation rate of the pressure wave, properly.
S. Yaghobi, Ch.b. Komaki, M. Hosseinalizadeh, A. Najafinejad, H.r. Pourghasemi, M. Faramarzi,
Volume 27, Issue 1 (Spring 2023)
Abstract
Frequency analysis of daily rainfall or return period of rainfall and flooding events is very important considering the behavioral complexity in water resources management; because ignoring it can lead to urban destructive floods. In the present research, three distribution functions of Pearson, Beta, and Gamma were compared to investigate and select the most appropriate distribution function for the precipitation data acquired from meteorology stations and CHIRPS satellite in seven stations in the watershed of Bustan Dam. Statistical analyses showed that satellite data were ineffective to estimate daily precipitation due to high errors in RMSE, MAD, and NASH. Meteorological data were used to spot the best distribution. Google Earth Engine and Python programming language were used. Then, the selected distribution function was used to determine the maximum daily rainfall, frequency probability, and return period of 2, 10, 50, 100, and 200 years. The results of the goodness of fit test, Error Sum of Squares, Bayesian Information Criterion, Akaike Information Criteria well as Kullback-Leibler Divergence showed that in five stations of Kalaleh, Qarnaq, Golestan National Park, Golestan Dam, and Glidagh, the Pearson function is the most suitable distribution function. Also, in the other two stations (Gonbad and Tamar), the Beta function was recognized as a suitable function. However, Gamma distribution in the study area is not efficient. So, it can be concluded that heavy and irregular rainfall can be effective in choosing the best distribution function at each station. Therefore, it is recommended to consider the maximum possible rainfall and as a result of the possible occurrence of floods with principled and accurate management to prevent human and financial losses in susceptible areas, especially in the study area.
