نوع مقاله : مقاله پژوهشی
نویسندگان
1 کارشناس ارشد منابع آب، دانشگاه شهرکرد
2 استادیار گروه مهندسی آب، دانشگاه شهرکرد
3 دانشیار گروه مهندسی آب، دانشگاه شهرکرد
چکیده
از جمله مهمترین چالشی که محققان در مدل سازی بارش- رواناب با آن رو به رو هستند به کارگیری نوع روش تلفات و جداسازی بارش موثر است که به طبع بر روی دقت مدل در تمام جزییات هیدروگراف تاثیر می‌گذارد. در این مطالعه، ابتدا شاخص نفوذ بر اساس ارتفاع رواناب، بارش و زمان موثر بارش مشخص شد. سپس هیدروگراف واحد لحظه ای از طریق روش روسو محاسبه و ابعاد هیدروگراف رواناب مستقیم برای 20 رویداد حوضه برآورد شد. سپس به جهت افزایش دقت در ابعاد هیدروگراف رواناب بدست آمده، مقدار شاخص نفوذ بر اساس توزیع دومتغیره حاصل از شاخص نفوذ و یکی از خصوصیات بارش یا رواناب با استفاده از توابع مفصل تخمین زده شد. بدین منظور، ابتدا همبستگی بین شاخص نفوذ و هر یک از خصوصیات بارش و رواناب مشخص و نوع توزیع‌های حاشیه‌ای مناسب هر متغیر مشخص شد. در نهایت تابع مفصل گالامبوس به عنوان بهترین تابع مفصل برای ایجاد توزیع های دومتغیره از شاخص نفوذ و ارتفاع بارش؛ شاخص نفوذ و حداکثر شدت جریان؛ شاخص نفوذ و متوسط شدت جریان و همچنین شاخص نفوذ و سرعت جریان انتخاب شد تا هیتوگراف بارش برای هر رویداد بدست آید. با مقایسه بین اجزای مختلف هیدروگراف محاسباتی و مشاهداتی از روش تابع مفصل با روش روسو مشخص شد که با استفاده از تابع مفصل می‌توان با دقت بیشتری مقدار شاخص نفوذ را تخمین زد.
کلیدواژه‌ها
عنوان مقاله [English]
Performance assessment of Copula functions in estimation of rainfall losses and rainfall-runoff modelling (Case study: Kasilian Watershed)
نویسندگان [English]
- fatemeh bayati 1
- rasoul mirabbasi 2
- Roohollah Fatahi Nafchi 3
- mahdi radfar 2
1 MS.c. of Water Resource Engineering
2 nullAssociate Professor, Department of Water Engineering, Shahrekord University
3 Associate Professor, Department of Water Engineering, Shahrekord University
چکیده [English]
One of the most important challenges of researchers in rainfall-runoff modelling is the estimation losses and extracting excess rainfall, which can affect on accuracy of the model and hydrograph characteristics. In the present study, at first the infiltration index of was estimated based on the depth of runoff and rainfall and also effective rainfall time. Then, instantaneous unit hydrograph was computed through Russo Method and the dimensions of direct runoff hydrograph were determined for 20 rainfall- runoff events. Then in order to increase the precision in estimating the dimensions of obtained hydrograph, the value of penetration index was estimated based on bivariate distribution resulted from infiltration index and one of rainfall characteristics which obtained from Copula function. For this purpose, at first the correlation between infiltration index of , characteristics of rainfall hyetograph and runoff hydrograph was calculated, then the best- fitted marginal distribution on each variable was specified. Finally, Galambos function was chosen as the best copula function for creating bivariate distribution for pairs of infiltration index of and rainfall height, infiltration index of and maximum velocity, infiltration index of and average flow and also infiltration index of and velocity. Therefore, the hydrograph dimensions were obtained for each event. Comparing the various dimensions of computed and observed hydrograph by copula function in Russo method showed that the infiltration index of can be estimated more accurately by using the copula function.
کلیدواژه‌ها [English]
- Rainfall-runoff
- Copula function
- Losses
- Infiltration index of
- Russo instantaneous unit hydrograph
- Abbasian,, S. Jalali and S. Mousavi. 2014. Multivariate analysis of flood frequency and distribution marginal joint function using parametric and nonparametric. Modares Civil Engineering Journal, 14(4): 81-92 (in Persian).
- Agha Kouchak, A., A. Bardossy and E. Habib. 2010. Conditional simulation of remotely sensed rainfall data using a non-Gaussian v-transformed copula. Advances in Water Resources, 33: 624-634 (in Persian).
- Ahmadi, A. and A. Fakhiri Fred. 2011. Comparison of hybrid and Nash models for extraction of unit hydrograph, case study of Lighvan Watershed. Journal of Water and Soil Science, 21(1): 29-41 (in Persian).
- Bahremand, R. and R. Mostafazadeh. 2010. Comparison of the efficiency of methods for estimating the parameters of the nitrogen hydrograph model in the simulation of flow hydrograph in Jafar Abad Basin. Journal of Watershed Research, 86: 42-51 (in Persian).
- Bahremand, A., A. Alvandi, M. Bahrami, M. Dashti Marvili, H. Haravi and Gh. KHosravi. 2014. Coppola functions and their application in stochastic hydrology. Journal of Conservation and Exploitation of Natural Resources, 4(2): 1- 20 (in Persian).
- De Michele, C. and G. Salvadori. 2003. A Generalized Pareto intensity-duration model of storm rainfall exploiting 2-Copulas. Journal of Geophysical Research, 108(2): 1-15 (in Persian).
- Gargouri-Ellouze, E. and Z. Bargaoui. 2012. Runoff estimation an ungauged catchment using Geomorphological Instantaneous Unit Hydrograph (GIUH) and Copulas. Water Recourse Management, 26: 1615-1638.
- Golkarian, A., A. Nagibi and D. Davoodi Moghaddam. 2014. Evaluation of the efficiency of geomorphology method in estimating the dimensions of a unit's hydrograph and comparing it with Snyder, SCS and triangular methods, case study: Kardeh Watershed. Journal of Soil and Water (Agricultural Sciences and Technology), 28(2): 440-450.
- Karami, F. and M. Ismail Pour. 2014. Estimation of runoff using geomorphologic moment unit hydrograph model, case study of Daryan Chay Basin. Journal of Hydrogeomorphology, 145 -157 (in Persian).
- Khaleghi, M. and J. Ghodoosi. 2010. Evaluation of the efficiency of geomorphologic unit hydrograph methods in estimating peak flood discharge. Quarterly Journal of Natural Resources Science and Technology, 5(2): 100-89 (in Persian).
- Mirabbasi, R., A. Fakheri-Fard and Y. Dinpashoh. 2012. Bivariate drought frequency analysis using the Copula method. Theoretical and Applied Climatology, 108: 191–206.
- Nelsen, R.B. 2006. An introduction to Copulas. Springer, New York, 269 pages.
- Rahimi, L., A. Dehghani, M. Abdolhosseini and KH. Ghorbani. 2014. Flood frequency analysis using the Archimedean copulas functions based on the series of annual maximum. Journal of Irrigation and Drainage, 8(2): 353- 365 (in Persian).
- Rodriguez-Iturbe, I., M. Gonzalez-Sanabria and R.L. Bras. 1982. A geomorphoclimatic theory on the instantaneous unit hydrograph. Water Resources Research, 18(4): 877–886.
- Saravanan, S. and R. Manjulia. 2015. Geomorphology based semi-distributed approach for modeling rainfall-runoff modeling using GIS. Aquatic Procedia, 4: 908-16.
- Rosso, R. 1984. Nash model relation to Horton order ratios. Water Resources Research, 20: 914- 920.
- Saeedi, P., M. Nick Sakhnam and Kh. Norouzi. 2015. Estimation of Geomorphologic Instantaneous Unit Hydrograph (GIUH) and Width-Function based Instantaneous Unit Hydrograph (WFIUH) in non-statistical basins, case study of Ghorveh Basin. Journal of Ecohydrology, 2(1): 51-62 (in Persian).
- Sahoo, B. and P.G. Saritha. 2015. Estimating floods from an ungauged river basin using GIUH-based Nash Model. International Symposium on Flood Research and Management, at: Kota Kinanbalu, Sabah, Malaysia, ISBN: 978-981-287-364-4 (Springer).
- Sayed Kabuli, H. and A. Akhund Ali. 2009. Evaluation of rainfall methods in flood hydrograph simulation. Water and Soil Journal (Agriculture Sciences and Technology), 6: 109-98 (in Persian).
- Rostamizade, Gh., Sh. Khaligi Sigaroodi and M. Mahdavi. 2013. Calibration of different methods for estimating rainfall losses in HEC-HMS model in order to simulate surface runoff, case study of Catchment. Rangeland and Watersheds of Iran, 66(3): 373-359 (in Persian).
- Shiau, J.T., S. Feng and S. Nadarajah. 2007. Assessment of hydrological droughts for the Yellow River China using copulas. Hydrological Processes, 21: 2157–2163.
)