تحلیل پیش بینی گروهی بارش مدل CFSv2 با رویکرد مدیریت منابع آب ( مطالعه موردی: حوضه آبریز سد دز)

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری/ مهندسی منابع آب، گروه هیدرولوژی و منابع آب، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز.

2 استاد/ گروه هیدرولوژی و منابع آب، دانشکده مهندسی منابع آب، دانشگاه شهید چمران اهواز

3 استادیار / گروه هیدرولوژی و منابع آب، دانشکده مهندسی منابع آب، دانشگاه شهید چمران اهواز.

چکیده

پیشرفت و بهبود پیش بینی های عددی ، موجب توجه بیش از پیش برنامه ریزان و بهره برداران سیستم های منابع آب به این اطلاعات شده است. اغلب ارزیابی ها در زمینه پیش بینی های فصلی ، بر مبنای داده های ایستگاهی زمینی و یا داده های شبکه بندی صورت می گیرد. در این تحقیق در راستای ارزیابی عملکرد پیش بینی مدل CFSv2 ،تحلیل‌ها در مقیاس حوضه آبریز انجام شده است و به منظور ایجاد یک سری زمانی با طول دوره مناسب جهت تحلیل ها، از ترکیب داده های مشاهداتی و پایگاه های داده بارش ماهواره مبنا PERSIANN-CDR استفاده گردید.
بر اساس معیار ضریب همبستگی و شاخص ROCscore، نتایج بیانگر این است که پیش دید 1 در بین پیش دیدهای پیش بینی ماهانه بهترین عملکرد را از لحاظ پیش بینی کمی بارش دارد هر چند برآوردهای آن نسبت به بقیه پیش دیدها کم برآوردتر می باشد. در تفکیک پیش بینی‌ها بر اساس چندک‌ها با سه طبقه به صورت زیرنرمال، نرمال و فرانرمال، نمایه های ROC-AUC و ROCscore نشاندهنده عملکرد مطلوب پیش بینی ها در چندکهای بارشی زیر 0/4 و بالای 0/6می باشد و در مقیاس ماهانه، ماه نوامبر با 0/88، دسامبر 0/66و ماه مارس 0/8، بیشترین نمایه ROC-AUC را به ترتیب در طبقه1، 2و 3 دارند. در بررسی طبقه بارش بر مبنای شاخص SPI نیز نتایج نشان می‌دهد که صحت پیش بینی صحیح طبقه خشکسالی 50 تا 60 درصد می باشد، در حالیکه با یک طبقه اختلاف در پیش بینی دقت نتایج تا 80 درصد افزایش می یابد.

کلیدواژه‌ها


عنوان مقاله [English]

Evaluation of CFSv2 Enssmble Precipitation Forecasts with Water Resources Management Application Perspective( Case Study: Dez Dam River Basin)

نویسندگان [English]

  • Seyyed majid Mousavi 1
  • Ali Mohammad AkhondAli 2
  • Ali Shahbazi 3
1 Ph.D Candidate of Water Recourses Engineering, Department of Water Resources, College of Water Sciences Engineering, Shahid Chamran University of Ahwaz, Ahwaz, Iran
2 Professor of Water Recourses Engineering Department of Water Resources, College of Water Sciences Engineering, Shahid Chamran University of Ahwaz, Ahwaz, Iran.
3 Assistant Professor of Water Recourses Engineering Department of Water Resources, College of Water Sciences Engineering, Shahid Chamran University of Ahwaz, Ahwaz, Iran.
چکیده [English]

Recent advances in numerical weather and seasonal forecasts ,make the water resources manager and operators very interested to involve the forecasts in real operation.Generally in the studies, the skill assessment of the forecasts would be done by comparing the forecasts with station gauge or gridded data which maight not reflect the real skill of the forecasts in basin scale. In this paper , the forecasts generated by the Noaa climate forecast system version 2( CFSv2) were evaluated in the Dez dam basin. A combination of rain gauge data with satelite base precipitation estimates( Persiann-CDR) were used as the basis of evaluation. Result showed monthly precipitation forecasts with lead 1 has the best performance based on R and ROCauc although the underestimation is higher than other leads. Evaluation of the forecasts in 3 different percentile including below normal, normal and above normal, showed well performance in percentiles above 0.6 and below 0.4, also best monthly forecast performance with lead1 was 0.88 for Nov, 0.66 for Dec and 0.8 for Mar respectively for percentile of category 1 to 3 based on ROCauc. Winter precipitation evaluation based on the SPI with 5 category, suggested that 50 to 60 percent of the times, the exact category was truly predicted while with on category difference the accuracy imrove up to 80 percent of the times.

کلیدواژه‌ها [English]

  • Persiann-CDR
  • CFSv2
  • Ensemble Forecast Verification
  • Seasonal Precipitation Forecast
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