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Estimation of Rainfall Values by using Soil Moisture as a Natural Measurment with SM2RAIN Algorithm (Case study: Orumia lake Catchment)

Fereydooni, Mehdi | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49631 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Tajrishy, Masoud
  7. Abstract:
  8. The direct impact of rainfall in human life and its fundamental role in water resources management cause the development of methods and algorithms to estimate the rainfall among the researchers. In the past decades the traditional methods were used to measure the amount of rainfall until the advent of Meteorological Satellites has sparked a revolution in this field. Significant temporal and spatial changes of rainfall and the small number of the synoptic stations caused negative impact on the actual distribution of the amount of rainfall in a vast area. The rainfall satellite data were somewhat overcome by existing deficiencies in Synoptic methods by providing a better rainfall distribution map. All of the above approaches and most of the models and softwares for rainfall estimation are “up to down”. In this study, the new approach “down to up” was used and by considering changes in soil moisture the amount of rainfall in the study area was simulated. The SM2RAIN algoritm was used with this approach and based on the water balance equation at the soil surface. In this algoritm all the components of water balance equation except rainfall were simulated. This algoritm has been used to simulate rainfall on a global scale and for a vast area. In this study, the algoritm was used to simulate rainfall in a small scale (sub-basin) that cause more attention to factors such as: vegetation, snow cover and amount of glacial in the region. In this study, AMSR2 and ASCAT satellites were used with 10, 25 km resolution and amount of rainfall was simulated for the following regions: Shabestar, Sahand, Khoy, Miandoab, Maragheh, Boukan. By surveying the various factors that caused errors in algoritm it was found that the factors such as: vegetations, glacial and snow cover , can significantly affect the performance of the model. By examining these factors in various regions and creating proper conditions, amount of rainfall with 0.8, 0.9 correlation coefficient in callibration and 0.75 correlation coefficient in algoritm validation was simulated. Applications of this research include the following: production and modification of rainfall data for the areas where data are not collected or the number of synoptic stations are low, completion of statistical gaps in data of synoptic stations, rainfall data production with higher accuracy and resolution according to the progress in the technology of soil moisture satellite data and continuous improvement of their resolution, spatial analysis of rainfall in various sub-basin and surveying the amount of runoff in a basin and etc
  9. Keywords:
  10. Urumieh Lake ; Water Balance ; Remote Sensing ; Rainfall Simulation ; Satellite Data ; Soil Moisture ; Soil Moisture to Rain (SM2RAIN)

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