Jahantab Khosrovanian; Majid Onagh; Masud Guderzi; Seyyedasadollah Hejazi
Volume 19, Issue 53 , September 2015, , Pages 93-115
Abstract
Abstract
A stochastic weather generator can serve as a computationally inexpensive tool to produce multiple-year climate change scenarios at the daily time scale which could incorporate changes both in mean climate and in climate variability as well. In this paper, LARS-WG model was used to downscale ...
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Abstract
A stochastic weather generator can serve as a computationally inexpensive tool to produce multiple-year climate change scenarios at the daily time scale which could incorporate changes both in mean climate and in climate variability as well. In this paper, LARS-WG model was used to downscale GCM outputs and then tp assess the performance for generated daily data of precipitation, minimum and maximum temperature and sunshine hours. Study area was Ghare-su basin in Gorgan and the station is called Gorgan synoptic station. The first step was running the model for the 1970-1999 periods. Then mean of observation and synthetic data were compared. T-test was used in the 99% significance level, and the difference between observation and synthetic data was not significant. Finally monthly mean of observation and synthetic data were compared using statistical parameters such as NA, RMSE & MAE. As a final result, it was found that performance of model was appropriate for generating daily above-listed data in Ghare-su basin. Thus, it was possible to predict the climatic parameters from GCM output using LARS-WG model. Also minimum and maximum temperatures had the highest and sunshine hours involved the lowest correlation. After ensuring performance of model to simulate above-mentioned parameters, this model used to predict future trends (in 2011-2030 and 2080-2099) with A2, A1B and B1 scenarios of the HadCM3 model was. Results showed that future temperature would increase 0.56-4.04 degrees centigrade while precipitation would increase 10.28-23.71%.
Majid Hosseini; Mohammad Ghafouri; Mahmoodreza Tabatabaee; Masood Godarzi; seyed asadollah Hejazi
Volume 17, Issue 45 , November 2013, , Pages 27-41
Abstract
One of the main concerns in recent years with regard to climate change and global warming is how to efficiently manage the water resources of the world. Insufficient or unavailable hydroclimatological data further aggravate the difficulty of good water management. Hence the use of hydrologic and hydraulic ...
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One of the main concerns in recent years with regard to climate change and global warming is how to efficiently manage the water resources of the world. Insufficient or unavailable hydroclimatological data further aggravate the difficulty of good water management. Hence the use of hydrologic and hydraulic models is a possible solution to ease the job of the water managers. In this research, Soil and Water Assessment Tools (SWAT) are used to predict and validate the discharge in Taleghan Watershed of Iran. The inputs required include soil, land use and DEM layers with hydroclimatological data. Statistical methods were used for calibration and validation of the SWAT model. The results indicate that the observed and predicted discharge have the least mean absolute relative error both in the annual and monthly periods. From the SPSS analysis, these values were found to be not significant at 95% probability for the annual and monthly discharges for the calibration and validation periods. The study illustrates the usefulness of the SWAT Model in predicting runoff components in a watershed. The annual results in Taleghan catchments during 1987 and 2007 indicate an increasing 7.3% surface runoff and decreasing 11.3% and 11% interflow and groundwater flow respectively.
Saeed Jahanbakhshasl; Majid Rezaeebanafsheh; Masood Godarzy; Abdolmohammad Ghaforyrozbehany; MohammadHossein Mahdiyan
Volume 16, Issue 41 , November 2012, , Pages 49-66
Abstract
One of the main objectives in hydrology is rainfall–runoff forecasting systems for determination of flood hydrograph in outlet of a watershed. Flood discharge could be estimated using rainfall-runoff models, which explain hydrological phenomena for un-gauged watersheds. The aim of this study was ...
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One of the main objectives in hydrology is rainfall–runoff forecasting systems for determination of flood hydrograph in outlet of a watershed. Flood discharge could be estimated using rainfall-runoff models, which explain hydrological phenomena for un-gauged watersheds. The aim of this study was to investigate the consistency, accuracy and reliability of time–area and Clark Instantaneous unit hydrograph models in estimating the shape, peak discharge, time to peak, time base and volume hydrograph of flood resulting from a rainfall with certain intensity and duration. For this purpose the topographic map of Bazoft watershed digitized by using R2V package, the digital elevation model (DEM) and isochronal prepared with the ILWIS software. Finally, the flood hydrographs were estimated by Clark and Time-Aria models for six selected storm events. The computed hydrographs then compared with those obtained by measured data. The results show that the Clark model gives a better estimation of outlet hydrograph in comparison with time-area model.
Masood Goodarzi; Saeed Jahanbakhsh Asl; Majid Rezaee Banafsheh
Volume 16, Issue 37 , November 2011, , Pages 133-149
Abstract
Flood risk estimation is one of the most important subjects for hydrologists and other scientists. The main objective of flood risk estimation is to study the past events in order to foresee the future flood risk. There are various methods for flood risk estimation. Rainfall- runoff and empirical equations ...
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Flood risk estimation is one of the most important subjects for hydrologists and other scientists. The main objective of flood risk estimation is to study the past events in order to foresee the future flood risk. There are various methods for flood risk estimation. Rainfall- runoff and empirical equations are among the most used methods. In these methods, rainfall is the main parameter influencing flood mechanism. In this research, spatial distribution of rainfall pattern in Esfahan province is studied. Esfahan province with 10.5 million hectars of area has located in the central part of Iran with different topography, climate and ecological condition. Over 203 rain-guages located in the study area and its neibourhood were studied. The duration base of data record was 33 years. A total of 1654 storm events with less than 1 hour to 72 hours duration were considered, in which three index events, i.e. widespread and maximum events were used. The common methods of geostatistics, Krigging, Co-Krigging, IDW and TPSS were applied to interpolate the recorded points to non-observed ones. Among the studied interpolating methods, Krigging shows the best results, from which the Gussian and spherical models best fits to the observed points. In order to gain the best results, it is recommended to add the number of rainfall guage sites according to the World Meteorological Organization (WMO) standards. Also, we propose grouping the study area into homogeneous regions and studying DAD in each homogeneous region is advised.
