Ataolah Kavian; 1 1; 1 1; 1 1; 1 1; 1 1; 1 1
Abstract
Small and portable rainfall simulators are essential tools in study of soil erosion and surface hydrology and it provide to repeat natural rainfall characteristics. In addition to the introduction of this device, calibration tests were performed including nozzles discharge evaluation, uniformity test ...
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Small and portable rainfall simulators are essential tools in study of soil erosion and surface hydrology and it provide to repeat natural rainfall characteristics. In addition to the introduction of this device, calibration tests were performed including nozzles discharge evaluation, uniformity test over the plots and raindrop size distribution. The results of nozzles discharge calibration showed that two nozzles discharge at 20, 40, 60 and 80 KPa pressure are similar and there isn't any significant difference between them. To achieve the optimum uniformity of simulated rainfall over the plot uniformity test was performed with changing nozzle distance (50, 60 and 70 cm) and oscillation of nozzles (30, 45 and 60 degrees) at constant operational pressure of 60 KPa. The results showed that the uniformity coefficient at 2m2 plot obtained from 57% to 61% and rainfall intensity changes from 48 to 101 mm/hr. The results of high velocity photography revealed median diameter of raindrop as 2.4 to 2.6 mm.
Abbas Gholami; Kaka Shahedi; Mahmud Habibneghad; Mahdi Vafakhah; Karim Solymani
Abstract
Present study is aimed at forecasting and comparison of future climate change by using GCM model (General circulation model) under different climate scenarios in Talar watershed of Mazandaran province. Regarding the data of existing stations, to study the climate change phenomenon in Talar watershed, ...
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Present study is aimed at forecasting and comparison of future climate change by using GCM model (General circulation model) under different climate scenarios in Talar watershed of Mazandaran province. Regarding the data of existing stations, to study the climate change phenomenon in Talar watershed, the LARS-WG5 model and 3 climate scenarios i.e. A1B, A2, B1, each in three emission series i.e. 2011-2026, 2046-2061, and 2080-2095, that were extracted from Gharakhayl regional synoptic stations in Quaemshahr, were used and the base year was considered 1992-2007( for a 15- year duration). Since this model is one of the most authentic statistical downscaling methods and its data is produced in three phases of calibration, evaluation and development of meteorological data, it was applied for research in present study. According to the findings, the most precipitaion changes occurred in May and October and the most severe reductive changes occurred in 2080-2095, the result of which warns about seasonal floods in rainy months and drought or water shortage in dry months in the relevant watershed study area. Besides, in future in June, July, August, and September temperature increase will be experienced but in January and February, the minimum simulated tempreture mean will be observed.