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Showing 4 results for Najafi
- Ali Najafinejad, - Hesam Heravi, - Abdolreza Bahremand, - Hossein Zeinivand,
Volume 7, Issue 1 (5-2020)
Volume 7, Issue 1 (5-2020)
Abstract
Simulation of Climate Change on river hydrograph Using WetSpa Model, Case Study: Taleghan Watershed Alborz Province
Abstract
Introduction: One of the major issues in hydrology engineering is the prediction of the flood routing or rising and falling limb river hydrograph, in which the importance of the climate is very evident due to the high volatility and is therefore one of the most important factors to be carefully studied. Climate has been changing ever since. Changes refer to the variability of the long term trends in the state of the climate or average changes in temperature and rainfall that persist for extended period. Important regional water resource vulnerabilities to changes in both temperature and precipitation patterns are documented. Recent analysis from the inter-governmental panel for climate change indicates that the earth as a whole has warmed by about 0.6°C ± 0.2°C over the past century with locally and seasonally varying amounts. The changes in pattern and intensity of precipitation, melting of ice, increasing atmospheric water vapor and others has a significant natural variability on inter annual to decadal that masking the long term trend. Increased evaporation, combined with changes in precipitation characteristics, has the potential to affect runoff, frequency and intensity of floods and droughts, soil moisture, and water supply. Warming of climate system and change in its state variables are highly related to the atmosphere-land-ocean system. The climate modeling science integrates these complex systems with the Global Circulation Models (GCMs) to simulate future climate changes and forecast it for decades and centuries. Climate change scenarios developed from General Circulation Models (GCMs) are the initial source of information for estimating plausible future climate changes. In regional and local climate studies usually coarse-resolution outputs of global climate models are downscaled to produce necessary fine scale data. Statistical downscaling methods are widely used for prediction of climatic variables e.g. precipitation because of importance of these factors in environmental planning and management. The main purpose of the research is to investigate the past and future potential of climate change and its impacts on the hydrologic response of the basin.
Data and method of work: In this study, the Taleghan Watershed of the Sefidrood basin was selected as a case study due to its socio-economic significance. Elevation range from 1774 to 4362 m and a mean slope is 40.5%. The mean annual precipitation in the catchment is 591 mm. At first using weather data and meteorological data with a daily step in a 21-year period and three base maps information, including precipitation data from eight stations, temperature and evaporation data from two stations were used as input to the model. Three base maps information i.e. DEM, land use and soil types are prepared in GIS and flow hydrograph was simulated using WetSpa model in Taleghan watershed. For runoff verification, the only river station at the outlet of the catchment was used. Then, for the reference period, daily modeled runoff was compared with observed values at available in the region. In the following Future climate change (precipitation, temperature and evaporation) based on CanESM2 model from the fifth report the Intergovernmental Panel on Climate Change (IPCC) on emission scenario RCP8.5 was used for simulating the flow hydrograph during the next period (2016-2029) and its comparison with the base period (1995-2015). In this study, the performance of Statistical Downscaling Model (SDSM) was investigated to predict precipitation, temperature and evaporation. Modeled precipitation was compared with observations of 8 available stations in the region, Observed temperatures from two stations were also used for modeled temperature and evaporation verification.
Interpretation of results: Regarding to the outputs and spatially distributed hydrological factors in daily time step the model is capable to analyze topography, soil type, and land use effects on the hydrological behavior of the watershed. Model evaluation results showed that The Nash-Sutcliffe criteria, 76% and accuracy of the simulation show the high performance of the model in this watershed. The results of the research showed that the SDSM model is well advanced to simulate Climate variables. Statistical measures of model performance such as Mean Absolute Error (MAE), Root Mean Squared Error (RMSE), Mean squared error (MSE) and the analysis of output results from SDSM model shown that this model is able to predict precipitation, temperature and evaporation indexes. According to the results of the CanESM2 model, in the considered scenario (RCP8.5), temperature will increase from 0.5 to 0.6 and Average precipitation in the future 8% will increase. Finally the results showed that in the considered scenario, the average runoff watershed will increase Up to 45% by the climate in the future. Also, the average of runoff will increase in all months of the year (except in October) compared to the base period. This increase is more pronounced for April.
Keywords: Emission Scenario, Flood, Hydrologic Model, River Hydrograph, Simulation
* Corresponding author: najafinejad@gau.ac.ir
Abstract
Introduction: One of the major issues in hydrology engineering is the prediction of the flood routing or rising and falling limb river hydrograph, in which the importance of the climate is very evident due to the high volatility and is therefore one of the most important factors to be carefully studied. Climate has been changing ever since. Changes refer to the variability of the long term trends in the state of the climate or average changes in temperature and rainfall that persist for extended period. Important regional water resource vulnerabilities to changes in both temperature and precipitation patterns are documented. Recent analysis from the inter-governmental panel for climate change indicates that the earth as a whole has warmed by about 0.6°C ± 0.2°C over the past century with locally and seasonally varying amounts. The changes in pattern and intensity of precipitation, melting of ice, increasing atmospheric water vapor and others has a significant natural variability on inter annual to decadal that masking the long term trend. Increased evaporation, combined with changes in precipitation characteristics, has the potential to affect runoff, frequency and intensity of floods and droughts, soil moisture, and water supply. Warming of climate system and change in its state variables are highly related to the atmosphere-land-ocean system. The climate modeling science integrates these complex systems with the Global Circulation Models (GCMs) to simulate future climate changes and forecast it for decades and centuries. Climate change scenarios developed from General Circulation Models (GCMs) are the initial source of information for estimating plausible future climate changes. In regional and local climate studies usually coarse-resolution outputs of global climate models are downscaled to produce necessary fine scale data. Statistical downscaling methods are widely used for prediction of climatic variables e.g. precipitation because of importance of these factors in environmental planning and management. The main purpose of the research is to investigate the past and future potential of climate change and its impacts on the hydrologic response of the basin.
Data and method of work: In this study, the Taleghan Watershed of the Sefidrood basin was selected as a case study due to its socio-economic significance. Elevation range from 1774 to 4362 m and a mean slope is 40.5%. The mean annual precipitation in the catchment is 591 mm. At first using weather data and meteorological data with a daily step in a 21-year period and three base maps information, including precipitation data from eight stations, temperature and evaporation data from two stations were used as input to the model. Three base maps information i.e. DEM, land use and soil types are prepared in GIS and flow hydrograph was simulated using WetSpa model in Taleghan watershed. For runoff verification, the only river station at the outlet of the catchment was used. Then, for the reference period, daily modeled runoff was compared with observed values at available in the region. In the following Future climate change (precipitation, temperature and evaporation) based on CanESM2 model from the fifth report the Intergovernmental Panel on Climate Change (IPCC) on emission scenario RCP8.5 was used for simulating the flow hydrograph during the next period (2016-2029) and its comparison with the base period (1995-2015). In this study, the performance of Statistical Downscaling Model (SDSM) was investigated to predict precipitation, temperature and evaporation. Modeled precipitation was compared with observations of 8 available stations in the region, Observed temperatures from two stations were also used for modeled temperature and evaporation verification.
Interpretation of results: Regarding to the outputs and spatially distributed hydrological factors in daily time step the model is capable to analyze topography, soil type, and land use effects on the hydrological behavior of the watershed. Model evaluation results showed that The Nash-Sutcliffe criteria, 76% and accuracy of the simulation show the high performance of the model in this watershed. The results of the research showed that the SDSM model is well advanced to simulate Climate variables. Statistical measures of model performance such as Mean Absolute Error (MAE), Root Mean Squared Error (RMSE), Mean squared error (MSE) and the analysis of output results from SDSM model shown that this model is able to predict precipitation, temperature and evaporation indexes. According to the results of the CanESM2 model, in the considered scenario (RCP8.5), temperature will increase from 0.5 to 0.6 and Average precipitation in the future 8% will increase. Finally the results showed that in the considered scenario, the average runoff watershed will increase Up to 45% by the climate in the future. Also, the average of runoff will increase in all months of the year (except in October) compared to the base period. This increase is more pronounced for April.
Keywords: Emission Scenario, Flood, Hydrologic Model, River Hydrograph, Simulation
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* Corresponding author: najafinejad@gau.ac.ir
Alireza Pilpayeh, Davoud Najafian Ghojehbiglou, Tofigh Saadi, Akbar Rahmati,
Volume 7, Issue 3 (11-2020)
Volume 7, Issue 3 (11-2020)
Abstract
Drought is one of the natural disasters occurring over a long period of time compared to other natural phenomena which intermittently impedes human societies through the negative impacts on water and agricultural resources and subsequently the economy. One of the methods of drought monitoring is the use of drought indices such as SPI. In this study, SPI index was used to study drought over the period 2001 to 2016. The SPI index is purely based on precipitation, so it is important to select a proper precipitation source to extract the SPI index at different time scales. Synoptic stations, due to lack of proper distribution and high statistical gaps, cannot be a reliable source of precipitation in this type of research, so global precipitation datasets having high spatial and temporal resolution can be used as a viable alternative to ground stations, in this study the Era-interim precipitation product, which is the product of the European Center for Medium range Weather Forecast was used. Initial results indicated that the Era-interim precipitation product could be used as a viable alternative to synoptic stations nationwide. Therefore, this precipitation product was used to assess the drought situation in the country. The study of drought status with respect to SPI indicated that with increasing SPI time scale dry and wet conditions became more severe so that mild dry and wet conditions in most in most month and years turned into severe dry and wet conditions.
Esmaiel Najafi, Dr Sayyad Irani Heris, Farshad Jafari,
Volume 7, Issue 4 (2-2021)
Volume 7, Issue 4 (2-2021)
Abstract
Abstract
Since the early 1990s, the idea of sustainable urban development has been a fundamental and very important issue for decision makers and thinkers. Because it encompasses the historical concept of development and at the same time has become very important in determining the current international, national and regional policies (Pugh, 2004). In recent years, governance has become a hot topic in public sector management, and this is due to the important role that governance plays in determining public health. Therefore, according to environmental resources, good governance means the way in which decision makers promote sustainable development, which includes the protection of the living environment (Shuakrizadeh and Ashrafi, 2011). Governance is the institutional capacity of public organizations to provide goods demanded by the public and to help the citizens of the country or their representatives efficiently, transparently, fairly, and with accountability to limited resources. This definition of governance represents an international organization and development institution such as the World Bank that seeks to support reforms through good governance programs aimed at strengthening the strategic capacity of donor governments while intending to engage civil society. Strengthen sovereignty. (Krueger,2007).
Environmental hazards and ecological crises are the result of the interaction of environmental, economic, cultural, health and even political variables. The scope of these variables is local-spherical, so that no place in the earth is far from its consequences, with the difference that the scope and depth of the crisis is severe and weak (Kaviani rad, 2010). Investigating the effects of environmental hazards in relation to sustainable development with a good governance approach is very important and very important in terms of nature, so the present study with descriptive-analytical approach and based on library and field studies to study the effects of environmental hazards on sustainable indicators of Mazandaran province It has dealt with the characteristics of decent humility. Brief descriptions of the concepts of sustainable development and development, environmental hazards and proper governance are also given in the text of the article.
The most important natural and human hazards in Mazandaran province are earthquakes, mass movements, floods, fires, droughts, frosts, pollution of water resources, soil erosion, pollution of agricultural products, urbanization and urban development, waste, etc. It brings a lot, attention to earth sciences and the environment can, in addition to preventing risks, accelerate the process of sustainable development.
The research method is descriptive-analytical and based on library and field studies. In order to gather information within the framework of theoretical foundations of research, by referring to library resources (Persian and Latin books, publications, dissertations and reputable foreign sites), the required materials have been collected. Statistics and information related to the development indicators of Mazandaran province have been extracted from the statistics of the Statistics Center of Iran and then examined with SPSS software, Table No. (3). The Cochran's formula was used to determine the sample size. The statistical population in this study is Mazandaran province and the population of the province in the general census of population and housing in 2016, 3,283,582 people, which by placing the total population of the region in the above formula with a probability level of 95% to calculate the sample size by estimating distributions. There were two sentences (Cochran). A total of 384 questionnaires were distributed among residents and officials in the study province, a simple random method.
Based on the appropriate governance indicators in relation to environmental hazards and sustainable development of Mazandaran province, it was evaluated as lower than average (2.78 with theoretical average 3). Based on the results of factor analysis after Warmax matrix period, the participation index shows the role of urban management in increasing people's participation in improving urban environment and reducing social anomalies in Mazandaran province and reducing environmental degradation (with a coefficient of 0.772). , In the index of accountability, accountability of urban managers to the demands and complaints of people about environmental degradation and employment status (with a coefficient of 0.645), in the index of effectiveness and efficiency, the effect of managers' programs on reducing pollution (air, water, etc.) and Increasing the quality of social and infrastructural indicators of sustainable development (0.772) and the variability of the effectiveness of the implemented projects On the part of environmental managers in the cities of Mazandaran province (with a coefficient of 0.720), in the transparency index, what is your level of knowledge about the approval of plans and programs to deal with the effects of environmental hazards on the development indicators of the province (with a coefficient of 0.660) ) And how much do you know about the budgets spent on environmental protection and development and development programs and job creation in the province (with a coefficient of 0.639), in the indicator of responsibility, willingness to accept responsibility in economic, social and environmental fields? What is the level of the neighborhood itself (with a coefficient of 0.592), in the index of the central law, the amount of legal treatment of officials with factors Local and regional pollutants are environmental degrading factors (with a coefficient of 0.8595), in the Justice and Equality Index, the government's attention to dealing with environmental degrading factors in the city and shortening the hand of land grabbers in Mazandaran province (with a coefficient of 0.739) They had a higher operating load.
In relation to the impact of human and natural hazards on sustainable development indicators, which clearly include environmental, economic and social indicators, justice and equality indicators and participation in Mazandaran province are better than other indicators. It shows that the indicators of transparency, accountability and rule of law are less than average in the eyes of the people and are not in a good position in this regard.
Since the early 1990s, the idea of sustainable urban development has been a fundamental and very important issue for decision makers and thinkers. Because it encompasses the historical concept of development and at the same time has become very important in determining the current international, national and regional policies (Pugh, 2004). In recent years, governance has become a hot topic in public sector management, and this is due to the important role that governance plays in determining public health. Therefore, according to environmental resources, good governance means the way in which decision makers promote sustainable development, which includes the protection of the living environment (Shuakrizadeh and Ashrafi, 2011). Governance is the institutional capacity of public organizations to provide goods demanded by the public and to help the citizens of the country or their representatives efficiently, transparently, fairly, and with accountability to limited resources. This definition of governance represents an international organization and development institution such as the World Bank that seeks to support reforms through good governance programs aimed at strengthening the strategic capacity of donor governments while intending to engage civil society. Strengthen sovereignty. (Krueger,2007).
Environmental hazards and ecological crises are the result of the interaction of environmental, economic, cultural, health and even political variables. The scope of these variables is local-spherical, so that no place in the earth is far from its consequences, with the difference that the scope and depth of the crisis is severe and weak (Kaviani rad, 2010). Investigating the effects of environmental hazards in relation to sustainable development with a good governance approach is very important and very important in terms of nature, so the present study with descriptive-analytical approach and based on library and field studies to study the effects of environmental hazards on sustainable indicators of Mazandaran province It has dealt with the characteristics of decent humility. Brief descriptions of the concepts of sustainable development and development, environmental hazards and proper governance are also given in the text of the article.
The most important natural and human hazards in Mazandaran province are earthquakes, mass movements, floods, fires, droughts, frosts, pollution of water resources, soil erosion, pollution of agricultural products, urbanization and urban development, waste, etc. It brings a lot, attention to earth sciences and the environment can, in addition to preventing risks, accelerate the process of sustainable development.
The research method is descriptive-analytical and based on library and field studies. In order to gather information within the framework of theoretical foundations of research, by referring to library resources (Persian and Latin books, publications, dissertations and reputable foreign sites), the required materials have been collected. Statistics and information related to the development indicators of Mazandaran province have been extracted from the statistics of the Statistics Center of Iran and then examined with SPSS software, Table No. (3). The Cochran's formula was used to determine the sample size. The statistical population in this study is Mazandaran province and the population of the province in the general census of population and housing in 2016, 3,283,582 people, which by placing the total population of the region in the above formula with a probability level of 95% to calculate the sample size by estimating distributions. There were two sentences (Cochran). A total of 384 questionnaires were distributed among residents and officials in the study province, a simple random method.
Based on the appropriate governance indicators in relation to environmental hazards and sustainable development of Mazandaran province, it was evaluated as lower than average (2.78 with theoretical average 3). Based on the results of factor analysis after Warmax matrix period, the participation index shows the role of urban management in increasing people's participation in improving urban environment and reducing social anomalies in Mazandaran province and reducing environmental degradation (with a coefficient of 0.772). , In the index of accountability, accountability of urban managers to the demands and complaints of people about environmental degradation and employment status (with a coefficient of 0.645), in the index of effectiveness and efficiency, the effect of managers' programs on reducing pollution (air, water, etc.) and Increasing the quality of social and infrastructural indicators of sustainable development (0.772) and the variability of the effectiveness of the implemented projects On the part of environmental managers in the cities of Mazandaran province (with a coefficient of 0.720), in the transparency index, what is your level of knowledge about the approval of plans and programs to deal with the effects of environmental hazards on the development indicators of the province (with a coefficient of 0.660) ) And how much do you know about the budgets spent on environmental protection and development and development programs and job creation in the province (with a coefficient of 0.639), in the indicator of responsibility, willingness to accept responsibility in economic, social and environmental fields? What is the level of the neighborhood itself (with a coefficient of 0.592), in the index of the central law, the amount of legal treatment of officials with factors Local and regional pollutants are environmental degrading factors (with a coefficient of 0.8595), in the Justice and Equality Index, the government's attention to dealing with environmental degrading factors in the city and shortening the hand of land grabbers in Mazandaran province (with a coefficient of 0.739) They had a higher operating load.
In relation to the impact of human and natural hazards on sustainable development indicators, which clearly include environmental, economic and social indicators, justice and equality indicators and participation in Mazandaran province are better than other indicators. It shows that the indicators of transparency, accountability and rule of law are less than average in the eyes of the people and are not in a good position in this regard.
Mr. Kaveh Bapirzadeh, Mr. Hesam Seyedkaboli, Miss Leila Najafi,
Volume 9, Issue 2 (9-2022)
Volume 9, Issue 2 (9-2022)
Abstract
A comparative study of quantitative mapping methods for bias correction of ERA5 reanalysis precipitation data
Kaveh Bapirzadeh1, Hesam Seyed kaboli*2, Leila Najafi3
1 MSc student, Department of Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran.
*2 Associate Professor, Department of Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran. Corresponding Author: Email: hkaboli@jsu.ac.ir
3 Instructor, Department of Civil Engineering, Jundi-Shapur University of Technology, Dezful, Iran.
Abstract
This study evaluates the ability of different quantitative mapping (QM) methods as a bias correction technique for ERA5 reanalysis precipitation data. Climate type and geographical location can affect the performance of the bias correction method due to differences in precipitation characteristics. For this purpose, ERA5 reanalysis precipitation data for the years 1989-2019 for 10 selected synoptic stations in climates with different topographic characteristics were received daily from the European Centre for Medium-Range Weather Forecasts (ECMWF) website. Bias correction of these data was performed using 5 quantitative mapping methods based on observational data in R software environment. Two-part evaluation and Taylor diagram were used to compare the performance of different methods. The results showed that the performance of the quantification mapping method depends on the performance functions, set of parameters and climatic conditions. In general, non-parametric methods of multiple mapping have better performance than parametric methods, so that the best performance is related to QUANT and RQUANT methods, among which DIST method has the weakest performance.
Keywords: Quantitative mapping, Bias correction, ERA5, ECMWF
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