Drought as a reversible climate phenomenon is an inevitable fact, especially in arid and semiarid... more Drought as a reversible climate phenomenon is an inevitable fact, especially in arid and semiarid areas. Therefore, predicting drought is important to deal with and mitigate its effects. Hydrological drought with its direct effect on water resources is the most important type of drought. It is caused by the lack of surface water flow and river discharge reduction. To measure its characteristics (magnitude and duration), Stream Flow Index (SDI) has been used. However, to predict hydrological drought, it is essential to understand its relationship with meteorological drought, which is described by the Standardized Precipitation Index (SPI). In this study, monthly rainfall and discharge data of Karoon and Maroon Basins in Iran from 1973 to 2014 were collected and used to calculate SDI and SPI indicators. Based on Run theory, drought characteristics, including drought duration and its magnitude, were obtained. In order to have a more reliable analysis of hydrological drought, which is a consequence of meteorological drought, the most suitable relationship between meteorological and hydrological drought characteristics was investigated. A significant relationship between meteorological and hydrological droughts was concluded by regression analysis; on average, the quadratic function showed the best performance. Based on the results, hydrological droughts occur on average at a 7-month interval from meteorological drought. Finally, spatial analysis of drought characteristics (duration and magnitude) was determined and performed by multivariate Copula functions.
AbstractThe focus of this paper is to investigate the flood vulnerability of a small but importa... more AbstractThe focus of this paper is to investigate the flood vulnerability of a small but important basin in Iran with emphasis on application of integrated flood management (IFM) concept to reduce negative effects of flooding. The study basin is a flood prone area where different ...
Drought as a reversible climate phenomenon is an inevitable fact, especially in arid and semiarid... more Drought as a reversible climate phenomenon is an inevitable fact, especially in arid and semiarid areas. Therefore, predicting drought is important to deal with and mitigate its effects. Hydrological drought with its direct effect on water resources is the most important type of drought. It is caused by the lack of surface water flow and river discharge reduction. To measure its characteristics (magnitude and duration), Stream Flow Index (SDI) has been used. However, to predict hydrological drought, it is essential to understand its relationship with meteorological drought, which is described by the Standardized Precipitation Index (SPI). In this study, monthly rainfall and discharge data of Karoon and Maroon Basins in Iran from 1973 to 2014 were collected and used to calculate SDI and SPI indicators. Based on Run theory, drought characteristics, including drought duration and its magnitude, were obtained. In order to have a more reliable analysis of hydrological drought, which is a consequence of meteorological drought, the most suitable relationship between meteorological and hydrological drought characteristics was investigated. A significant relationship between meteorological and hydrological droughts was concluded by regression analysis; on average, the quadratic function showed the best performance. Based on the results, hydrological droughts occur on average at a 7-month interval from meteorological drought. Finally, spatial analysis of drought characteristics (duration and magnitude) was determined and performed by multivariate Copula functions.
Abstract This study investigates the performance of multiple high-resolution remotely sensed prec... more Abstract This study investigates the performance of multiple high-resolution remotely sensed precipitation estimates at hourly and daily time scales over Canada for 2014–2018. Four products of the recently released Integrated Multi-satEllite Retrievals for Global precipitation measurement (IMERG-V06) and the Multi-Radar Multi-Sensor (MRMS) Precipitation Rate data are analyzed for different seasons. Evaluations are based on a suite of metrics to assess different characteristics of precipitation estimates using quality-controlled hourly gauge data considered as the truth. The results suggest that Calibrated precipitation (PrecipitationCal) outperforms the other IMERG products particularly over the Prairies and during fall and summer. Over the western and eastern coastal regions, IMERG tends to overestimate precipitation intensities by ~25%. The discrepancy between satellite and ground-based data is higher for more intense precipitation events. Further analyses indicate that while MRMS tends to overestimate the amount of precipitation, it outperforms the IMERG products based on several metrics, especially in detecting the occurrence of precipitation over the eastern coastal regions. Overall, the study of IMERG V06 and MRMS precipitation estimates at a relatively high temporal resolution indicates that both products have the potential to complement ground-based observations over Canada.
2010 International Conference on Chemistry and Chemical Engineering, 2010
AbstractThe focus of this paper is to investigate the flood vulnerability of a small but importa... more AbstractThe focus of this paper is to investigate the flood vulnerability of a small but important basin in Iran with emphasis on application of integrated flood management (IFM) concept to reduce negative effects of flooding. The study basin is a flood prone area where different ...
Sensitivity Analysis in Earth Observation Modelling, 2017
Abstract In this chapter, we discuss the use of copula model in uncertainty analysis of satellite... more Abstract In this chapter, we discuss the use of copula model in uncertainty analysis of satellite precipitation products, followed by a validation experiment of the generated ensembles. Daily events during 2003–05 of two widely used satellite rainfall estimates (SREs) named PERSIANN and TMPA-3B42V7 along with the rain gauge observations as true reference data have been employed. The emphasis is on how two elliptical copulas (Gaussian and t) can simulate multivariate ensembles of bias-adjusted SREs while preserving the dependency between input variables. To examine this feature of copulas and also analyze the sensitivity of randomly generated ensembles on the type of copula, two factors named P and R are computed and implemented. The obtained results indicate that the copula-based model is robust enough in uncertainty analysis and adjusts the bias of SREs, particularly for t-copula, which performs better than Gaussian type.
In this paper, the El-Hames empirical method was used to determine the peak runoff flow in Iransh... more In this paper, the El-Hames empirical method was used to determine the peak runoff flow in Iranshahr catchment. The El-Hames method is based on morphological parameters and SCS Curve Number of the studied area. The implementing was processed by collecting the required data including soil type and vegetation cover, land use maps, digital elevation model and satellite images from the associated institutions such as Iran Water Resources Management Company (IWRM) and Iran Weather Organization. Then the all data was integrated by using GIS in order to create different layers of required information. The generated layers were applied to determine the morphological parameters through SCS method and to develop the CN map of the study area. Afterward, daily rainfall statistics over the study catchment obtained from synoptic and rain-gauge stations were estimated for 2 to 200 year return periods. Finally, the developed curve number map and the rainfall statistics were imported in the El-Hames...
Due to the immense damage caused by dam failure, especially dams constructed near large cities, i... more Due to the immense damage caused by dam failure, especially dams constructed near large cities, it is necessary to consider the breaking phenomena as well as studying and designing different parts of the dam. For this purpose, the hydrograph of the outflow due to dam failure must be identified according to size of the fracture and then flood routing, and flood zone must be determined based on the downstream topography and morphology. The integration of hydraulic models and geographic information system is used to achieve this objective. In this research the effect of breaking Taleghan storage dam due to the slip of a pile of reservoir abutment and the creation of current wave toward the dam body as well as the vulnerability analysis due to the breaking of the dam on downstream lands was studied. At first, Taleghan dam failure for five different scenarios was modeled using the FLOW-3D numerical software and then the geometric data of the river was extracted using the ArcGIS software ...
Operation of multi-reservoir systems is known as complicated and often large-scale optimization p... more Operation of multi-reservoir systems is known as complicated and often large-scale optimization problems. The problems, because of broad search space, nonlinear relationships, correlation of several variables, as well as problem uncertainty, are difficult requiring powerful algorithms with specific capabilities to be solved. In the present study a Self-adaptive version of Melody Search algorithm is presented and applied to obtain Operating Rule Curves for multi-reservoir systems. The self-adaptive mechanism is implemented to satisfy problems constraints and perform algorithm parameters evolution going through different iterations. The research initially evaluates capability of extended algorithm using eight benchmark problems comparing other well-known metaheuristic algorithms, and verifies its effectiveness. Then, the algorithm is adopted for optimal operation of a four-reservoir system located in Karkheh river basin to properly meet agricultural requirements and to decrease the pr...
Due to uncertainty in the nature of indirect remotely sensed precipitation products, bias adjustm... more Due to uncertainty in the nature of indirect remotely sensed precipitation products, bias adjustment is a crucial step. In this research, bias adjustment of Integrated Multi-satellitE Retrievals for GPM (Global Precipitation Measurement) (IMERG) snowfall estimates with 0.1° spatial resolution and half-hour temporal resolution was performed over a basin located in the Western United States based on Snowpack Telemetry (SNOTEL) ground station snow accumulation (SA) observations using the Gridded based Bias Adjustment using Copula (GBAC) approach. After dividing the study area into several boxes, usual and unusual pairs of cumulative distribution functions (CDFs) were separated in station pixels. Then, simulated biases were obtained using multivariate copula functions in station boxes. Next, based on the T copula function, bias adjustment bands were generated during the calibration period in station pixels. This step was followed by the validation stage. Also, bias adjustment bands were generated in pixels with no station. Based on calibration results, in boxes located west of 120° W, the range between the lower bound and the 10th percentile of the band had the most impact on satellite SA adjustment. Conversely, in boxes located east of 120° W, the middle range of the band (between 10th and 90th percentiles) was more effective. Thus, longitude was an effective factor in satellite SA bias adjustment. The validation results showed that in station boxes with a longitude over 120° west, the adjustment band was narrower. This is while in station boxes with longitude less than 120° west, the bias adjustment band better encompassed the ground SA data.
Drought as a reversible climate phenomenon is an inevitable fact, especially in arid and semiarid... more Drought as a reversible climate phenomenon is an inevitable fact, especially in arid and semiarid areas. Therefore, predicting drought is important to deal with and mitigate its effects. Hydrological drought with its direct effect on water resources is the most important type of drought. It is caused by the lack of surface water flow and river discharge reduction. To measure its characteristics (magnitude and duration), Stream Flow Index (SDI) has been used. However, to predict hydrological drought, it is essential to understand its relationship with meteorological drought, which is described by the Standardized Precipitation Index (SPI). In this study, monthly rainfall and discharge data of Karoon and Maroon Basins in Iran from 1973 to 2014 were collected and used to calculate SDI and SPI indicators. Based on Run theory, drought characteristics, including drought duration and its magnitude, were obtained. In order to have a more reliable analysis of hydrological drought, which is a consequence of meteorological drought, the most suitable relationship between meteorological and hydrological drought characteristics was investigated. A significant relationship between meteorological and hydrological droughts was concluded by regression analysis; on average, the quadratic function showed the best performance. Based on the results, hydrological droughts occur on average at a 7-month interval from meteorological drought. Finally, spatial analysis of drought characteristics (duration and magnitude) was determined and performed by multivariate Copula functions.
AbstractThe focus of this paper is to investigate the flood vulnerability of a small but importa... more AbstractThe focus of this paper is to investigate the flood vulnerability of a small but important basin in Iran with emphasis on application of integrated flood management (IFM) concept to reduce negative effects of flooding. The study basin is a flood prone area where different ...
Drought as a reversible climate phenomenon is an inevitable fact, especially in arid and semiarid... more Drought as a reversible climate phenomenon is an inevitable fact, especially in arid and semiarid areas. Therefore, predicting drought is important to deal with and mitigate its effects. Hydrological drought with its direct effect on water resources is the most important type of drought. It is caused by the lack of surface water flow and river discharge reduction. To measure its characteristics (magnitude and duration), Stream Flow Index (SDI) has been used. However, to predict hydrological drought, it is essential to understand its relationship with meteorological drought, which is described by the Standardized Precipitation Index (SPI). In this study, monthly rainfall and discharge data of Karoon and Maroon Basins in Iran from 1973 to 2014 were collected and used to calculate SDI and SPI indicators. Based on Run theory, drought characteristics, including drought duration and its magnitude, were obtained. In order to have a more reliable analysis of hydrological drought, which is a consequence of meteorological drought, the most suitable relationship between meteorological and hydrological drought characteristics was investigated. A significant relationship between meteorological and hydrological droughts was concluded by regression analysis; on average, the quadratic function showed the best performance. Based on the results, hydrological droughts occur on average at a 7-month interval from meteorological drought. Finally, spatial analysis of drought characteristics (duration and magnitude) was determined and performed by multivariate Copula functions.
Abstract This study investigates the performance of multiple high-resolution remotely sensed prec... more Abstract This study investigates the performance of multiple high-resolution remotely sensed precipitation estimates at hourly and daily time scales over Canada for 2014–2018. Four products of the recently released Integrated Multi-satEllite Retrievals for Global precipitation measurement (IMERG-V06) and the Multi-Radar Multi-Sensor (MRMS) Precipitation Rate data are analyzed for different seasons. Evaluations are based on a suite of metrics to assess different characteristics of precipitation estimates using quality-controlled hourly gauge data considered as the truth. The results suggest that Calibrated precipitation (PrecipitationCal) outperforms the other IMERG products particularly over the Prairies and during fall and summer. Over the western and eastern coastal regions, IMERG tends to overestimate precipitation intensities by ~25%. The discrepancy between satellite and ground-based data is higher for more intense precipitation events. Further analyses indicate that while MRMS tends to overestimate the amount of precipitation, it outperforms the IMERG products based on several metrics, especially in detecting the occurrence of precipitation over the eastern coastal regions. Overall, the study of IMERG V06 and MRMS precipitation estimates at a relatively high temporal resolution indicates that both products have the potential to complement ground-based observations over Canada.
2010 International Conference on Chemistry and Chemical Engineering, 2010
AbstractThe focus of this paper is to investigate the flood vulnerability of a small but importa... more AbstractThe focus of this paper is to investigate the flood vulnerability of a small but important basin in Iran with emphasis on application of integrated flood management (IFM) concept to reduce negative effects of flooding. The study basin is a flood prone area where different ...
Sensitivity Analysis in Earth Observation Modelling, 2017
Abstract In this chapter, we discuss the use of copula model in uncertainty analysis of satellite... more Abstract In this chapter, we discuss the use of copula model in uncertainty analysis of satellite precipitation products, followed by a validation experiment of the generated ensembles. Daily events during 2003–05 of two widely used satellite rainfall estimates (SREs) named PERSIANN and TMPA-3B42V7 along with the rain gauge observations as true reference data have been employed. The emphasis is on how two elliptical copulas (Gaussian and t) can simulate multivariate ensembles of bias-adjusted SREs while preserving the dependency between input variables. To examine this feature of copulas and also analyze the sensitivity of randomly generated ensembles on the type of copula, two factors named P and R are computed and implemented. The obtained results indicate that the copula-based model is robust enough in uncertainty analysis and adjusts the bias of SREs, particularly for t-copula, which performs better than Gaussian type.
In this paper, the El-Hames empirical method was used to determine the peak runoff flow in Iransh... more In this paper, the El-Hames empirical method was used to determine the peak runoff flow in Iranshahr catchment. The El-Hames method is based on morphological parameters and SCS Curve Number of the studied area. The implementing was processed by collecting the required data including soil type and vegetation cover, land use maps, digital elevation model and satellite images from the associated institutions such as Iran Water Resources Management Company (IWRM) and Iran Weather Organization. Then the all data was integrated by using GIS in order to create different layers of required information. The generated layers were applied to determine the morphological parameters through SCS method and to develop the CN map of the study area. Afterward, daily rainfall statistics over the study catchment obtained from synoptic and rain-gauge stations were estimated for 2 to 200 year return periods. Finally, the developed curve number map and the rainfall statistics were imported in the El-Hames...
Due to the immense damage caused by dam failure, especially dams constructed near large cities, i... more Due to the immense damage caused by dam failure, especially dams constructed near large cities, it is necessary to consider the breaking phenomena as well as studying and designing different parts of the dam. For this purpose, the hydrograph of the outflow due to dam failure must be identified according to size of the fracture and then flood routing, and flood zone must be determined based on the downstream topography and morphology. The integration of hydraulic models and geographic information system is used to achieve this objective. In this research the effect of breaking Taleghan storage dam due to the slip of a pile of reservoir abutment and the creation of current wave toward the dam body as well as the vulnerability analysis due to the breaking of the dam on downstream lands was studied. At first, Taleghan dam failure for five different scenarios was modeled using the FLOW-3D numerical software and then the geometric data of the river was extracted using the ArcGIS software ...
Operation of multi-reservoir systems is known as complicated and often large-scale optimization p... more Operation of multi-reservoir systems is known as complicated and often large-scale optimization problems. The problems, because of broad search space, nonlinear relationships, correlation of several variables, as well as problem uncertainty, are difficult requiring powerful algorithms with specific capabilities to be solved. In the present study a Self-adaptive version of Melody Search algorithm is presented and applied to obtain Operating Rule Curves for multi-reservoir systems. The self-adaptive mechanism is implemented to satisfy problems constraints and perform algorithm parameters evolution going through different iterations. The research initially evaluates capability of extended algorithm using eight benchmark problems comparing other well-known metaheuristic algorithms, and verifies its effectiveness. Then, the algorithm is adopted for optimal operation of a four-reservoir system located in Karkheh river basin to properly meet agricultural requirements and to decrease the pr...
Due to uncertainty in the nature of indirect remotely sensed precipitation products, bias adjustm... more Due to uncertainty in the nature of indirect remotely sensed precipitation products, bias adjustment is a crucial step. In this research, bias adjustment of Integrated Multi-satellitE Retrievals for GPM (Global Precipitation Measurement) (IMERG) snowfall estimates with 0.1° spatial resolution and half-hour temporal resolution was performed over a basin located in the Western United States based on Snowpack Telemetry (SNOTEL) ground station snow accumulation (SA) observations using the Gridded based Bias Adjustment using Copula (GBAC) approach. After dividing the study area into several boxes, usual and unusual pairs of cumulative distribution functions (CDFs) were separated in station pixels. Then, simulated biases were obtained using multivariate copula functions in station boxes. Next, based on the T copula function, bias adjustment bands were generated during the calibration period in station pixels. This step was followed by the validation stage. Also, bias adjustment bands were generated in pixels with no station. Based on calibration results, in boxes located west of 120° W, the range between the lower bound and the 10th percentile of the band had the most impact on satellite SA adjustment. Conversely, in boxes located east of 120° W, the middle range of the band (between 10th and 90th percentiles) was more effective. Thus, longitude was an effective factor in satellite SA bias adjustment. The validation results showed that in station boxes with a longitude over 120° west, the adjustment band was narrower. This is while in station boxes with longitude less than 120° west, the bias adjustment band better encompassed the ground SA data.
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