Showing 19 results for Rdi
S.j. Khajeddin,
Volume 4, Issue 3 (10-2000)
Abstract
Plant communities of the Kolah-Ghazi National Park have been studied. The park with a wide diversity of fauna and flora species is located 36 Km south of Isfahan. 214 plant species were collected for the purposes of this study. Plant communities of the park are of an aridland vegetation type. Minimal areas of the plant communities were determined using nested plots technique. After studying the Species/Area curves, a l00-square-meter quadrat was employed to collect the cover and density data for each species. The cover data were analysed to determine plant communities using the ordination method.
Crown cover of the vegetation was found to be poor and varied from zero to a maximum of five percent in the park. The following species form the major plant communities in the park: Artemisia sieberi, Anabasis aphylla, Acantholimon spp., Cousinia piptocephala, Ebenus stellata, Pteropyrum aucheri & Scariola orientalis. The combination of these species with others forms plant communities and subcommunities. The overlapping of habitats makes mosaics which cause the formation of ecotones, thus increasing the diversity of the subcommunities in the park. Mesophytic plant communities are narrowly scattered along streams. Most of the plant communities are controlled by the adaphic factor while the biological factor has only a limited control. A Ficus spp. specimen was also collected from the mountainous region in the park which could be a new species or variety and requires further study.
A. A. Vali,
Volume 10, Issue 1 (4-2006)
Abstract
Saline soils and halophytic vegetations are common features and part of the habitat pattern in deserts and steppes. The saline area is developing in arid lands. Investigation effects of halophytes on soil characteristics and adaptive mechanisms of the various halophyte types is essential for controlling saline environments. Juncus gerardi is a perennial grass-like halophyte and Halocnemum strobilaceum is a succulent halophyte shrub. The distribution of these species is mound like in the field. The soil samples of the mounds for investigating the effect of these species on plant root environment were compared with near regions in Korsiah saline area in Darab. Also the consentration some ions of live and dead organs and tissues of these species were studied for recognition of their adapive types. The results show that Juncus gerardi decrease salinity in 0-30 cm of topsoil, therefore the Ec decreased 37%. But salinity increased significantly in 30-60 cm depth. The identification of ions in plant tissues showed that the concentration of ions is low in dry matter. This is 0.33% of dry matter for Sodium. This is a way to rescue from dry conditions by selective absorption of ions. The comparison of root environment of Halocnemum strobilaceum with near regions showed a significant decrease in salinity in 0-30 cm and 30-60 cm depth decreased 27% and 40% respectively. The identification of ions concentrations in plant tissues reflect the high amounts of ions, therefore the plant tissues composed of 8.18% of Sodium. The comparision of ion concentrations in different live and dead tissues of plants a Significant increase of the amounts of ion in the dead tissues in comparison with the live tissues. Therefore this species excrete much quality of salts in their dead tissues and organs and so combat this problem.
E. Zandi Esfahan, S. J. Khajedin, M. Jafari, H. Karimizadeh, H. Azarnivand,
Volume 11, Issue 40 (7-2007)
Abstract
In order to determine the reciprocal relationship between the important characteristics of soil and the growth of Haloxylon ammodendron (C.A. Mey) plant in segsi plain of Isfahan., ordination method was used. The study was performed through the stratified random sampling and the regions were separated according to the plant age and physical physiognomy, then 10 samples of Haloxylon ammodendron (C.A. Mey) of the same age were selected in each region. Meanwhile, factors such as height, canopy cover area, canopy cover perimeter, canopy cover diameter, and basal area were considered. Also, 30 profiles from viewpoint of growth situations in 10 different regions were dug. Soil characteristics such as : pH, Ec, total soluble Ca2+ and Mg2+, Cl-, CO3--, HCO3-, SP%, CaCO3%, CaSO4%, organic matter%, total nitrogen percentage, phosphorous, Na+, K+, SAR, and hardpan depth were measured. Data was analyzed using ordination method. According to the results, samples of the same age showed significant differences in plant features. Other results showed that physical characteristics such as depth of hardpan from soil surface, SP%, and chemical characteristics such as salinity, alkalinity and total nitrogen had the highest effect on qualities of this kind of plant. In other words, the results mentioned above showed the important role of Haloxylon ammodendron (C.A. Mey) in sharp increase of salinity and alkanity in it's stratum.
F. Amiri, J. Khajeddin, K. Mokhtari ,
Volume 12, Issue 44 (7-2008)
Abstract
Ordination is the part of statistical ecology which has developed and integrated in recent years. Finding environmental factors which important in ecological structure determination of plant species is the final purpose of ordination. Ordination method was used for finding the effect of important variables on Bromus tomentellus species quantitative and qualitative changes in Esfahan's Fereidan region. For this purpose, fifteen sites were studied. Density, Cover percentage and Soil factors containing EC, pH, % caco3 , % gravel and stone, % clay, % silt, % sand, Na+, Ca2+, K+, Mg2+, Cl-, SAR, C/N and % OC. In A (0-30 cm) and B (30-60 cm) horizons over a line transaction in each site, were measured. The matrix of environmental and species characteristics were prepared. The relationship between environmental and species characteristics were determined using of PC-ORD and CANOCO software's and Redundancy Detrended Analysis (RDA) method. The results show that there are meaningful correlation between Density and Cover percentage with soil factors. The results implicate that C/N factor in A horizon and SAR in B horizon have the most effect on Bromus tomentellus density and cover percentage. EC, pH and …. Factors don't have much effect on Bromus tomentellus species characteristics.
E. Vaseghi , A. Esmaeili,
Volume 12, Issue 45 (10-2008)
Abstract
This study used a Ricardian approach to measure the impact of climate change on Iranian wheat production and analyzed potential impacts of further climate changes. The study utilized time series data for the period 1984-2004 pooled over 17 provinces. Results showed that climate change has significant nonlinear impacts on net revenue per hectare of wheat in Iran. The results also showed that rise in temperature and reduction in rainfall by the year 2100 will cause the reduction in land value by 41 %, because of increased greenhouse gas emission.
H Ghobari, H Goldansaz, H Askari,
Volume 13, Issue 47 (4-2009)
Abstract
One of the most important pest in the Oak forest of Kurdistan province is Oak leaf roller moth, Tortrix viridana L. (Lep.: Tortricidae). Use of pheromone trap is one of the suitable methods for monitoring and controlling of the pest. In this work, three main factors which affect the efficiency of traps including trap type, pheromone dose and installation height trap were studied. Four types of trap including cylindrical, rectangular, delta and wing trap were tested. Capture efficiency of the traps, were installed in the middle, and top heights of the trees were compared. Three doses of pheromone 0.5, 1, and 1.5 mgr per trap were also compared. Results showed that there were significant differences among four types of traps. Cylindrical, rectangular and delta traps caught more number of moths than wing trap (P<0.05). There were no significant differences between two installation heights (P>0.05). However, a significant differences was observed among three doses (P<0.05), and the dose of 0.5 mg caught more moths than the other three doses. Therefore cylindrical traps containing 0.5mg of synthetic sex pheromone installed in the middle of the trees canopy may be recommended in the management program of the pest.
B Rabiei, M Rahimi,
Volume 13, Issue 47 (4-2009)
Abstract
Discrimination function analysis is a method of multivariate analysis that can be used for determination of validity in cluster analysis. In this study, Fisher’s linear discrimination function analysis was used to evaluate the results from different methods of cluster analysis (i.e. different distance criteria, different cluster procedures, standardized and un-standardized data). Furthermore, Hotelling T2, CCC plot and multivariate analysis of variance were used to support the results. To achieve the goals, 8 rapeseed genotypes were planted in a randomized complete block design with three replications in Rice Research Institute of Iran, Rasht, durin 2005-2006, and 14 characteristics were measured. Analysis of variance based on the randomized complete block design showed significant differences between genotypes for all the studied traits. Comparison of means between genotypes indicated that the genotype Hyola401 for grain yield and most of the measured characteristics was better than the other genotypes. Evaluation of phenotypic and genotypic coefficient of variations showed that most of the traits had high variability in the population. Discrimination function analysis showed that the Euclidean distance criterion was better than others and a desirable clustering was obtained by this criterion. Also, all of the data standardization methods produced similar clusters and were better than un-standardized data. Based on evaluation of dendrograms derived from different methods of cluster analysis determined that the UPGMA, complete linkage and Ward’s minimum variance methods were better than the other methods, and grouped the genotypes into three clusters. Fisher’s linear discrimination function analysis showed that UPGMA and Ward's minimum variance methods with clustering validity of 87.5 percent, was more suitable than other cluster analysis methods however, discrimination analysis grouped genotypes into two clusters. Tests of Hotelling T2, CCC plot and multivariate analysis of variance supported the results from the discrimination function analysis. It seems that the UPGMA and Ward's minimum variance procedures based on Euclidean distance criterion of standardized data function better in grouping genotypes, yet, the use of discrimination function analysis is recommended to confirm the results and determine the actual groups.
L. Khodakarami, A. Soffianian, N. Mirghafari, M. Afyuni, A. Golshahi,
Volume 15, Issue 58 (3-2012)
Abstract
Among the environmental pollutants, heavy metals according to their irresolvable and physiological effects on living organisms at low concentrations, are of special importance These elements due to low mobility are gradually accumulated in soil Being accumulated in soil, they eventually enter the food chains and threaten human health and other creatures Therefore, studying concentration distribution of heavy metals for soil pollution monitoring and maintaining environmental quality is essential In this study we investigated the effect of agricultural land use and geology on the concentration of heavy metals contamination of soil and spatial distribution map, using collected data, GIS and GeostatisticsUsing systematic stratified random sampling, 135 surface soil samples( 0-20 cm) from an area of 7262 sq km area and we measured total concentration of elements Nickel, Chromium and Cobalt and soil characteristics including pH, organic matter and texture. The mean value of elements concentrations turned out to be Cr: 88.9+22.7 Co: 17.6+3.5 Ni 63.1+17.7 mg per kg and the mean acidity is 7.8 which in the area is an indication …… property. Formetal concentrations interpolation procedures, Geostatistics was used. By the aid of spatial correlation analysis, appropriate interpolation method using functions mean absolute error and bias average error were selected. Interpolation map concentrations of heavy metals Chromium, Cobalt and Nickel with ordinary kriging method and the exponential model were developed Interpolation map analysis of heavy metals by the aid of geological and land use maps show that the distribution of the elements Chromium, Cobalt and Nickel are consistent with the geology classes However, they did not match the agriculture pattern Findings of this study in the area give us appropriate information about the concentration distribution of heavy metals Chromium, Cobalt and Nickel which can be used in monitoring and evaluation processes of heavy metals pollution in agricultural lands area. But on the other hand sampling in the areas far away from human effects, showed that the heavy metals concentration is naturally high.
E. Gavili Kilaneh, M.r. Vahabi,
Volume 16, Issue 59 (4-2012)
Abstract
Vegetation is the most important factor in sustainable and dynamic equilibrium of natural ecosystems. Considering the relation between environmental factors and vegetation is an essential step in order to identify the effective factors in the habitats. The purpose of this study was to evaluate the relations between vegetation and soil characteristics in rangelands of Ferydounshahr (Sardab-Sibak watershed). The flora and vegetation types were studied using Physionomic-floristic method in the field and eight vegetation types were identified. Vegetation was sampled by Systematic–randomized method in 1× 2 m plots. The canopy cover and species composition percentage were estimated in each plot. After digging a soil profile in vegetation types, the physical and chemical factors were measured. The influences of edaphic factors on vegetation were analyzed using RDA ordination technique. Results showed that based on soil characteristics the eight vegetation types can be classified in to three main range habitats including, Ferula ovina, Astragalus adscendens and Astragalus brachycalyx. The most important factors which cause the separation in these three habitat ranges were clay percentage, organic matter, soil depth, CaCO3, pavement and barren soil.
M. Najafi-Ghiri, A. R. Mahmoodi, S. Askari,
Volume 19, Issue 72 (8-2015)
Abstract
Potassium (K) is an important cation in saline soils of arid lands, and its content, distribution and availability may be affected by native plants. To study the effect of halophyte species on different K forms in Korsia region located in western Darab (Fars province), three dominant halophyte species including Juncus gerardi, Halocnemum strobilaceum, and Salsola rigida were selected. Sampling was done from soils in canopy and between plants at the depth of 0-15 (surface) and 15-30 cm (subsurface) in triplicate. Soil physical and chemical properties including soil texture, organic matter, calcium carbonate, pH, cation exchange capacity, saturation percentage and electrical conductivity and different K forms including soluble, exchangeable and non-exchangeable were determined. Results indicated that organic matter, CEC, pH, and EC were affected by plant species. Juncus gerardi increased exchangeable K and decreased soluble K, but it had no effect on non-exchangeable and HNO3-extractable K. Halocnemum strobilaceum significantly increased soluble, exchangeable and HNO3-extractable K in surface and subsurface soils rather than soils between plants. This finding may be due to K uptake by plants from subsoils and also transfer of soluble K from soils between plants to roots. Salsola rigida had no effect on K status. Generally, soils between plants had more soluble and exchangeable K in surface than subsurface horizon. The studied halophyte species showed differences in growth and development pattern, soluble salts and K absorption and secretion, grazing by livestock, returned organic matter to soil, soluble salts and K reserves in their organs, and water uptake and thereby water and K diffusion from soil far from rhizosphere to roots, which may have different effects on K distribution in soils. Juncus gerardi, as regards effects on decreasing salinity and soluble K and increasing exchangeable K, may be recommended as a suitable species for remediation of the studied soils.
M. Nouri, M. Homaee, M. Bannayan,
Volume 22, Issue 1 (6-2018)
Abstract
In this study, the trends of changes of the standardized precipitation index in a 12-month timescale (SPI-12) and seasonal and annual precipitation were investigated in 21 humid and semi-arid stations of Iran during the 1976-2014 time period. After removing the serial correlation of some series, the trend of precipitation and SPI-12 was detected using the Mann-Kendall nonparametric trend test. The results revealed that the trends of annual precipitation had been declining in all stations over the past 39 years. The seasonal precipitation trend in winter, spring, autumn and summer was downward in approximately 90, 95, 47 and 37% of the studied stations, respectively. In addition, the descending trend of wintertime precipitation was significant in Sanandaj, Khoy, Urmia, Hamedan, Mashhad, Torbat-e-heydarieh, Nozheh and Qazvin. Also, the temporal trend of SPI-12 was decreasing in all surveyed stations except Shahrekord. Furthermore, SPI-12 showed a significant downward trend only in Sanandaj and Fasa. Moreover, the most severe meteorological drought occurred in the period 1999-2000, in Ramsar, Urmia and Hamedan, and in the period 2008-2009, in Tabriz, Sanandaj, Shiraz, Fasa, Qazvin, Mashhad, Torbat-e-heydarieh, Shahrekord, Gorgan and Kermanshah stations. Overall, the results of this study indicated that the trend of precipitation in most studied sites, particularly in semi-arid parts of the northeast and southwest of Iran, has changed due to the severe and long metrological drought that has occurred in the recent decade (2005-2015).
H. Faghih, J. Behmanesh, K. Khalili,
Volume 22, Issue 1 (6-2018)
Abstract
Precipitation is one of the most important components of water balance in any region and the development of efficient models for estimating its spatiotemporal distribution is of considerable importance. The goal of the present research was to investigate the efficiency of the first order multiple-site auto regressive model in the estimation of spatiotemporal precipitation in Kurdistan, Iran. For this purpose, synoptic stations which had long time data were selected. To determine the model parameters, data covering 21 years r (1992-2012) were employed. These parameters were obtained by computing the lag zero and lag one correlation between the annual precipitation time series of stations. In this method, the region precipitation in a year (t) was estimated based on its precipitation in the previous year (t-1). To evaluate the model, annual precipitation in the studied area was estimated using the developed model for the years 2013 and 2014; then, the obtained data were compared with the observed data. The results showed that the used model had a suitable accuracy in estimating the annual precipitation in the studied area. The percentages of the model in estimating the region's annual precipitation for the years 2013 and 2014 was obtained to be 7.9% and 17.3%, respectively. Also, the correlation coefficient between the estimated and observed data was significant at the significance level of one percent (R=0.978). Furthermore, the model performance was suitable in terms of data generation; so the statistical properties of the generated and historical data were similar and their difference was not significant. Therefore, due to the suitable efficiency of the model in estimating and generating the annual precipitation, its application could be recommended to help the better management of water resources in the studied region.
F. Moosiri, N. Ganji Khorramdel, M. Moghaddasi,
Volume 22, Issue 1 (6-2018)
Abstract
To continue or develop the exploitation of underground water for different different uses and purposes, as well as building any water structure, set of quantitative features of aquifers can be detected. To achieve this goal, quantitative monitoring of groundwater level is only possible. Accordingly, this study compared the impact of both the concept of marginal entropy and ordinary kriging for groundwater level monitoring network design in the case Gotvand-Aghili Plain, Khuzestan province. It is important to note that a key aspect in groundwater level monitoring of the quantity measured was the variability or uncertainty in it. This created a considerable confidence to monitor and ultimately achieve favorable conditions in the future. In this study, the variability of the groundwater level was considered to evaluate the combined effects of marginal entropy and ordinary kriging. In order to determine the suitable areas for further monitoring or thinning as well as the compatibility of these two methods, the monitor network design was designed. The map classified according to the marginal entropy method, in a range between 0.07 to 5.26 of the marginal entropy change, areas with the higher rates of 2.13 in terms of density; this indicated the need for more observation wells. Ordinary Kriging method also changed the range of values; they also represented areas that needed monitoring more than 13.16. Comparison of the results obtained by the two methods showed that the marginal entropy of the kriging method with less uncertainty and by using it, there was less the need to be monitored and classified. Comparison of the two methods by the zoning map showed that fewer errors were taken to the marginal entropy method and it could be recommended for the groundwater level monitoring network design. The network was also based on the Cross validation estimation error evaluated. These tests and additional analysis were employed in this study to determine the suitable areas for the higher density of wells and the need for thinning areas. The results further confirmed the proper performance of the methods employed, as well as the superiority of the marginal entropy in the design of a small groundwater monitoring network.
S. Ekhtiary Khajeh, F. Negahban, Y. Dinpashoh,
Volume 23, Issue 2 (9-2019)
Abstract
In this study, drought characteristics of Arak, Bandar Anzali, Tabriz, Tehran, Rasht, Zahedan, Shiraz and Kerman stations during the statistical period of 1956 to 2015 were studied by Reconnaissance Drought Index (RDI) and Standardized Precipitation Index. Precipitation and temperature data were needed to calculate RDI. Precipitation data was also required to estimate SPI. In this study, Drinc software was used to calculate RDI, SPI and potential evapotranspiration (PET). The software calculated PET by the Thornthwaite method. One of the main challenges in drought monitoring is to determine the indicator that has a high reliability based on its monitoring purpose. Therefore, in this research, two methods used for selecting the appropriate index based on the minimum rainfall and normal distribution were evaluated. The results of the evaluation of the minimum rainfall method for selecting the appropriate index showed that most drought indices with the occurrence of minimum rainfall level indicated severe or very severe drought situations; in most cases, it could not lead to selecting an exact and unique index. Based on the results of the normal distribution method for the stations of Arak, Tabriz, Rasht, Zahedan, Shiraz and Kerman, SPI index, and for the stations of Bandar Anzali and Tehran, RDI index were selected as the most appropriate ones.
E. Soheili, H. Malekinezhad, M. R. Ekhtesasi,
Volume 23, Issue 4 (12-2019)
Abstract
The Kor River in Fars province supplies an important part of water requirement in the Doroodzan dam basin and its surrounding area. In this study, the meteorological and hydrological droughts of this area were investigated in the last four decades. For this purpose, the temporal and spatial trend variability of the stream flow was investigated in monthly, seasonal, and annual time scales in the 6 selected stations. The trends of Standardized Precipitation Index SPI, as the drought index, in the 5 selected stations were also studied by the modified Mann-Kendall method. The results indicated that the trend in the stream flow was decreasing in all time scales. Significant downward trends were observed at 95% confidence level on monthly, annual and monthly time scales, especially in the warm months from May to September. These significant downward trends were located spatially in the stations located near the agriculture area, in the middle part of the basin. The significant upward trend existed only at the Doroodzan dam station, at the outlet in the area and in the warm months of the year. In the case of the SPI index, trends were decreasing in all time scales and were significant only at 2 stations in the long-term periods, 9, 12, and 18 months, at 95% confidence level. The results, therefore, indicated the occurrence of severe droughts (SPI<-2) during 1982-83 and 2007-8 periods.
F. Saniesales, S. Soltani, R. Modarres,
Volume 25, Issue 2 (9-2021)
Abstract
Several indices are used for drought identification and quantification. In this paper, the new Standardized Palmer Drought index (SPDI) was introduced and then the drought condition of Chaharmahal-Va-Bakhtiari Province was studied using this index. For this study, 11 synoptic, climatology, and evaporation meteorology stations were selected. Essential information in this investigation includes monthly temperature, monthly precipitation, and soil moisture measurement. To estimate SPDI, moisture departure, was first calculated on a monthly time scale. Then, converted to cumulative moisture departure values in different time scales including 3, 6, 9, 12, and 24 months. The best statistical distribution (GEV) was then fitted to cumulative departure. These values were then standardized to have the SPDI. The results showed that, as soil moisture affects SPDI estimation, it will be more valid for analyzing and monitoring drought conditions, especially for agricultural drought. Also, the results showed that 2000, 2001, and 2008 years were the driest time in this Province from 1988 to 2012. Moreover, drought frequency was found out in the western half of the Province more than in the other parts.
S. Banihashemi , S. S. Eslamian, B. Nazari,
Volume 25, Issue 2 (9-2021)
Abstract
The upcoming climate change has become a serious concern for the human society. These changes, caused and aggravated by the industrial activities of the international community and the increase in the concentration of greenhouse gases in the atmosphere, are seen as a threat to the food security and environment. Temperature change and precipitation are studied in the form of different probabilistic scenarios in order to have an outlook for the future. The present study was conducted to address the effects of climate changes on temperature and precipitation in Qazvin plain in the form of five AOGCMs including Hadcm3, CSIRO-MK3, GFDL, CGCM3 and MICROC3.2, and 3 greenhouse gas emission scenarios of A1B, A2 and B1, based on different possible scenario combinations in the next 30 years, 2021-2050 and 2051-2080 (near and far future). On basis of the study results, all 4 target stations, on average, will have experienced a change between two ratios of 0.5 and 1.4 of the observed precipitation period by the end of 2050, and the mean temperature will have had a change between -0.1 to 1.6 °C, relative to the observed period. By the end of 2080, the precipitation will also have fluctuated between the two proportions of 0.5 and 1.7 times of the observed precipitation period and the mean temperature will touch an increase between 0.6 and 2.6 °C. Both SPI and SPEI indices suggest the increment in the number of dry periods in the near and far future. However, the total number of negative sequences differed considering the 3, 12 and 24-month intervals at the stations level. Given the SPEI index, as compared to the base period, the total negative sequences of drought and number of dry periods will increase at 3 stations of Avaj, Bagh-Kowsar and Shahid-rajaei-powerhouse and decrease at Qazvin station in the future; however, SPI gives different results, such that for Bagh-Kowsar, there will be an increase in both total negative sequences of drought and number of dry periods, as compared to the baseline period; three other stations will have more dry periods, specifically, but less total negative sequences. The results reported that the drought events would become severe, and the wet events would become extreme in the future.
H. Ahmadzadeh, A. Fakheri Fard, M.a Ghorbani, M. Tajrishy,
Volume 25, Issue 3 (12-2021)
Abstract
In drought risk management, the regional analysis of drought is significant. In this paper, this important issue is investigated by presenting the new hydrological regional drought index (RDI). For this purpose, the Ajichai basin was selected as the study area. First, the time series of the streamflow drought index (SDI) was calculated for each of the hydrometric stations in the basin f regional analysis of hydrological drought. Then, to determine the homogeneous regions in terms of hydrological drought, the k-means method was used for clustering analysis. Based on the clustering results, 6 Homogeneous regions were identified in the basin. For each of these regions, the time series of the RDI index was calculated from 1365 to 1393. The results showed that during the study period in each of the regions 1, 2, 3, 4, 5, and 6, mild Wet and mild drought has occurred at 82.1, 80.1, 78.9, 83.3, and 84.3 percent of regions, respectively. Also, the total percentage of drought events (moderate and high) is higher than the total percentage of wet events (moderate and high) in all regions. So, during the study period, the total percentage of drought events (moderate and high) is more than twice the total percentage of wet events (moderate and high) in regions 2 and 3.
M. Ahmadi, H. Ramezani Etedali, A. Kaviai, A.r. Tavakkoli,
Volume 27, Issue 1 (5-2023)
Abstract
Studying the effects of drought in mountainous areas is facing problems due to the inappropriate distribution of stations, the lack of long-term data, and areas lacking statistics. Therefore, the main objective of this research was to investigate the drought indices of Kurdistan province using TRMM satellite data and ECMWF dataset, as well as to evaluate their accuracy against the data of land stations in Kurdistan province. First, ECMWF precipitation data for the 2000-2020 period and TRMM precipitation data for the 2000-2019 period were obtained and evaluated using RMSE, MBE, and correlation coefficient statistics. Spearman's correlation coefficient showed a significant relationship between the TRMM satellite precipitation data and the ECMWF dataset with ground stations at the 5% level, and the value of this coefficient was between 0.95-0.85. According to the results, it can be acknowledged that the TRMM satellite rainfall and ECMWF dataset in the monthly time scale had proper accuracy at the Kurdistan province level. Therefore, these two sources were used to examine the drought indices. SPI, SPEI, and ZSI drought indices were calculated in different monthly periods (1-48), PNI in different monthly, seasonal, and annual periods in Kurdistan province (Saqqez, Qorveh, Bijar, Sanandaj stations). Spearman's correlation coefficient indicated a significant relationship at the 5% level between the SPI, ZSI, PNI, and SPEI index of the ECMWF dataset with ground stations. The results of the SPI index showed that the lowest RMSE value for the TRMM satellite at the Saqqez station and the three months was equal to 0.45, and for the ECMWF dataset at the Sanandaj station and the 24 months was equal to 0.35.
