ارزيابي عملكرد مدل هاي هيدرولوژيكي توزيعي و يكپارچه در شبيه سازي متوسط روزانه دبي جريان درحوضه آبريز رودخانه قره سو ـ اردبيل

Evaluation of the Application Distributed and Lumped Hydrologic Models in Simulation of Mean Daily Flow Discharge in Gharasoo river basin in Ardebil (Iran)

- در اين مطالعه، عملكرد مدل هاي هيدرولوژيكي توزيعي MIKE SHE و يكپارچه MIKE NAM براي شبيه سازي متوسط روزانه دبي در حوضه آبريز رودخانه قره سو با مساحت حدود 4100 كيلومتر مربع واقع در استان اردبيل ارزيابي و مقايسه شده است. به منظور اطمينان از شبيه سازي صحيح فرآيندهاي هيدرولوژيكي به وسيله‌ي هر دو مدل، دبي شبيه سازي شده با دبي مشاهداتي مربوط به ايستگاه هيدرومتري ساميان واقع در خروجي حوضه آبريز براي سال 2003 كاليبره و براي سال 2004 صحت‌ سنجي و با بهره گيري از معيارهاي ارزيابي دقت، مقايسه شده اند. براي ارزيابي كارايي مدل در دوران واسنجي و صحت سنجي از معيارهاي ريشه ميانگين مربعات خطا (RMSE)، انحراف استاندارد باقي مانده ها (STDres)، ضريب همبستگي (r) ،ضريب بازده همبستگي نش- ساتكليف (E)، خطاي برآورد دبي بيشينه و خطاي برآورد زمان اوج بهره گرفته شده است. بر اساس معيار بازده كارايي مدل در دوران واسنجي و صحت سنجي كه به ترتيب مقادير 71 و 63 درصد را به خود اختصاص داده اند؛ نتايج به دست آمده از شبيه سازي حوضه با استفاده از مدل توزيعي MIKE SHE نشان مي دهد كه اين مدل قابليت مناسبي در شبيه سازي دبي متوسط روزانه جريان در مقياس حوضه آبريز دارد. همچنين مقدار ضريب بازده 83 و 60 درصد به ترتيب براي دوران واسنجي و صحت سنجي نشان مي دهد كه مدل يكپارچه MIKE NAM در شبيه سازي دبي متوسط روزانه جريان در مقياس حوضه آبريز قابليت مناسبي دارد. البته با توجه به ضريب بازده محاسبه شده در دوره صحت سنجي، مدل توزيعي MIKE SHE نسبت به مدل يكپارچه MIKE NAM، عملكرد بهتري را داشت.

In this research, MIKE SHE distributed hydrologic model and MIKE NAM lumped hydrologic model has been used for simulation of mean daily flow discharge in Gharasoo river basin in Ardebil province (Iran). Generally in the distributed models, the whole watershed is divided to small elements and the amount of each effective parameter on watershed for each element is considered separately. While in lumped models, watershed is considered as an integrative unit and effective parameters on watershed are considered with their intermediate quantity. Progressed and comprehensive hydrological models for more accurate calculation of flow discharge in watershed have been highly applied in recent years and progresses performed in the development of distributed and physically based models, oriented the research towards the evaluation and comparative studies with other models including lumped models.Because of the lack of the correct knowledge of complex hydrologic cycle in consequence of incorrect planning of water resources in watersheds, it is necessary to take an effective act for calculating flow discharge by using progressed and comprehensive models in direction of stable development of watersheds in our country. As mentioned above, the application of distributed and lumped models has been evaluated in simulation of mean daily flow discharge in Gharasoo river basin.The watershed area is about 4100 Km2 and its elevation ranges from 1200 to 4788 m above the mean sea level. the study area lies between 470 45ʹ and 480 40ʹE longitude and 370 49ʹ and 380 30ʹ N latitude. The average annual precipitation of this study area is about 284 mm. The most part of the study area has been covered by grass lands and crop lands. For confidence of correct simulation of hydrological processes by both models, the simulated discharge has been compared with observed discharge related to Samiyan hydrometry station that situated in out of the watershed for calibration and validation periods by using of evaluation criteria. The evaluation criteria including Root Mean Squre Error (RMSE), Standard Deviation of the Residuals (STDres), Correlation Coefficient (r) and Nash Sutcliffe Correlation Efficiency(E) have been used for evaluation of the application of the modeles along calibration and validation periods.The MIKE SHE model simulated daily discharge well as corroborated by correlation coefficients of 0.85 and o.80, root mean square errors of 4.0571 and 1.598 m3/s, standard deviation of the residuals of 4.0523 and 1.6m3/s and nash sutcliffe correlation efficiencyof 0.71 and 0.63 respectively for calibration and validation periods. The MIKE NAM model simulated daily discharge well as corroborated by correlation coefficients of 0.87 and o.78, root mean square errors of 3.13 and 1.6651 m3/s, standard deviation of the residuals of 3.122 and 1.6650m3/s and nash sutcliffe correlation efficiencyof 0.83 and 0.60 respectively for calibration and validation periods. The results of comparision between two models show that both of the models have appropriate application in simulation of mean daily flow discharge in the watershed. Also according to the calculated coefficient of efficiency in validation period, MIKE SHE distributed model had more appropriate application than the MIKE NAM lumped model