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- 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
Mr. Hamidreza Parastesh, Dr. Khosro Ashrafi, Dr. Mohammad Ali Zahed,
Volume 9, Issue 3 (12-2022)
Volume 9, Issue 3 (12-2022)
Abstract
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Cinq-Mars, TJ.; T. Kropotova, M. Morgunova, A. Tallipova, and S. Yunusov. 2020. Leak Detection and Repair in the Russian Federation and the United States: Possibilities for Convergence. Stanford US-Russia Forum Journal.
Weller, ZD.; DK. Yang, and JC. von Fischer. 2019. An open source algorithm to detect natural gas leaks from mobile methane survey data. PLoS One,14(2):e0212287.
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Estimation of methane gas leakage from Mashhad urban landfills and evaluation of economic and environmental effects
Abstract
This study, which was conducted in 8 urban gas areas of Mashhad; At first, descriptive statistics of the state of Mashhad urban gas regulators and different leakage modes were presented; In order to analyze the collected data and investigate the causes of leakage, the relationship between 5 variables and the amount of leakage from gas regulators was tested with the Statistical Package for the Social Sciences (SPSS) V.26 software; These 5 variables are: regulator equipment/connections, regulator operation age, regulator service type (domestic, industrial and commercial), urban area and different seasons of the year.
The results of the analysis showed that there was a significant difference between the type of equipment/connections and leakage. (P-Value = 0.0001). Also, a significant difference was observed among other variables of the research (the operation age of the regulator, the type of regulator service (domestic, industrial and commercial), the urban area and different seasons of the year) with the leakage rate (P-Value=0.0001); The pressure drop due to the greater demand of gas consumption in the winter season has reduced the amount of leakage compared to other seasons; The influence of the age of distribution network equipment/connections due to wear and tear and longer life will aggravate the amount of methane gas leakage; Also, the amount of leakage in commercial places had a significant difference with other types of uses; Being in an urban area has also increased the amount of methane gas leakage compared to other areas; The type and quality of equipment and connections as the main and influential factor in methane gas leakage should be considered by managers and officials in this field of work.
Keyword: Methane, Riser, Urban area, Environmental effects, Economy Effects, Gas, Emission
Dr Ghasem Azizi, Dr Samaneh Negah, Dr Nima Farid Mojtahedi, Mr Yossef Shojaie,
Volume 10, Issue 1 (5-2023)
Volume 10, Issue 1 (5-2023)
Abstract
Abstract
The continuous and expanding process of global warming, especially in the Asian region, has provided the conditions for increasing drought and the spread of desertification. Many deserts had ecologically balanced soil conservation conditions that until recently have become new sources of dust generation now. Numerous examples have occurred in Iran due to its special geographical location among some of the most important deserts in the world. Temperature anomaly (about 8º C) last winter in the Caspian Sea basin has created new dust sources for the southern coastal of the Caspian Sea. On 30-31 May 1400, dust emission was recorded in meteorological stations of Gilan province in terms of area and concentration. The implementation of HYSPLIT chemical backward models shows the emission of dust from the northwestern region of the Caspian Sea to the southern coastal of the Caspian Sea (Guilan province) for the first time with such intensity. The source and origin of this dust was identified in the Rhine desert in the northwest of the Caspian Sea. Continuous and unprecedented warming in the region and accompanied by strong north-south currents provided the conditions for the emission of this dust. Due to the origin of the emitted dust as well as the geographical and topographical conditions of the Caspian Sea basin, the level of this dust was assessed from the ground level to an altitude of less than 1500 meters. Analysis of synoptic conditions using NCEP / NCAR analysis data with 1 degree horizontal resolution indicates the establishment of high pressure air mass with a center of 1018 hPa on the northwestern parts of the Caspian Sea and the penetration of high pressure to the southern coastal areas of the Caspian Sea. Due to the appropriate pressure gradient and increasing wind speed, dust-producing springs are formed on the desert areas of the Rhine and with the dominance of the northern currents (south-south), the dust mass is sent to Gilan province.
Keywords: Global Warming, Dust emission, Russian Rhine Desert, Gilan.
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