ﭘﻬﻨﻪﺑﻨﺪﻯ قدرتﻓﺮﺳﺎﻳﻨﺪﮔﻰ باران به روش فورنیهبا استفاده از برخی روﺵﻫﺎﻯ ﺩﺭﻭﻥﻳﺎﺑﻰ(مطالعه موردی: استان قزوین)
محورهای موضوعی : جنگلداری
حسن احمدی
1
(
-استاد، گروه مهندسی ﺁبخیزداری، دانشگاه ﺁزاد اسلامی، واحد علوم تحقیقات تهران، تهران، ایران
)
کلید واژه: کریجینگ, IDW, واژﻩﻫﺎﻱکلیدی: استان قزوین, فرسایندگی باران, مدل فورنیه, دروﻥﻳﺎﺑﻲ,
چکیده مقاله :
چکیده در تحقیق حاضر فرسایندگی باران در استان قزوین از طریق مدل فورنیه و بر اساس دوره ﺁماری 20 ساله(1368-1387) ایستگاﻩﻫﺎﻱ سازمان هواشناسی (سینوپتیک، کلیماتولوژی و بارانسنجی) و سازمان ﺁب منطﻘﻪﺍﻯ مدﻝﺳﺎﺯﻯ و برﺁورد شده است. جهت تعمیم دادﻩﻫﺎﻯ ﻧﻘﻄﻪﺍﻯ مقادیرقدرت فرسایندگی در مدل فورنیه به سطح، در استان قزوین از روش کریجینگ و IDWاستفاده شد و برای ارزیابی روﺵﻫﺎﻯ دروﻥﻳﺎﺑﻰ از روش ارزیابی متقابل و معیار RMSEبهره گرفته شد که بر اساس ﺁن روشIDW به دلیل کمتر بودن خطای مجذور مربع میانگین(59/6) مناﺳﺐﺗﺮ از روش کریجینگ (23/7) تشخیص داده شد. همچنین از واریوگرام با مدل نمایی به عنوان مدل مناسب جهت برازش استفاده گردید. مدﻝﺳﺎﺯﻯ و برﺁورد فرسایندگی باران در استان قزوین ازطریق توابع تحلیل مکانی سیستم اطلاعات جغرافیایی و نرﻡﺍﻓﺰﺍﺭ انجام گرفت.نتایج نشان داده که میزان قدرت فرسایندگی باران در نواحی شمال و ﺷﻤﺎﻝﺷﺮﻕ استان با میانگین حداقل و حداکثر بارش سالانه(1/216 و 9/776) و چند نقطه در جنوب غرب استان با میانگین حداقل و حداکثر بارش سالانه (2/205 و751) بیشﺗﺮﯾﻦ مقدار ضریب فرسایندگی باران را دارا هستند که چنین تغییراتی ﻣﻰﺗﻮﺍﻧﺪ متاثر از الگوی توزیع بارندگی، شدت ﺁن و خصوصیات توپوگرافی باشد. نهایتاً سطح استان به 4 پهنه فرسایشی ناچیز، کم، متوسط و زیاد تقسیم شد.
Abstract In this study rainfall erosivity in Ghazvin province has been modeled and estimated through the application of Fournier model and based on a 20-year statistical period (1368-1388) of meteorological bureaus (synoptic, climatology and rain gauge) and Regional water organization. To generalize point data of erosivity strength ratio in Fournier model to the surface, in Ghazvin province, Kriging and IDW methods have been used. In addition, to evaluate interpolation methods, cross validation and RMSE criterion have been employed. Accordingly, IDW method was identified to be more appropriate, due to the less error in mean chi-square (6/59) than Kriging method (7/23). Also, Variogram with exponential model was used as the proper model for fitting. Modeling and evaluation of rainfall erosivity in Ghazvin province were performed by location analysis function of Geographic Information System and GS+ software. The data indicate that north and northeastern regions and some parts in the southwest of the province, with minimum/maximum rainfall of (216.1- 776.9) and (205.2- 751) respectively, have the highest rainfall erosivity ratio. These changes could be influenced by rain distribution patterns, the amount of rainfall, and the topographical characteristics of the region. Ultimately, 4 different regions with insignificant, low, medium and high erosive ratios were distinguished in Ghazvin province.
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