Comprehensive evaluation of seasonal forecasts from NMME and statistical models over the Blue Nile Basin and the Grand Ethiopian Renaissance Dam (GERD) watershed

Study region: The Blue Nile basin, including the Grand Ethiopian Renaissance Dam (GERD) Study focus: This study evaluates the performance of seasonal precipitation forecasts from the North American Multi-Model Ensemble (NMME) over the Blue Nile Basin and compares them to newly developed statistical...

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Main Authors: Mekonnen Gebremichael, Yu-Chuan Tien, Vahid Nourani
Format: Article
Language:English
Published: Elsevier 2025-02-01
Series:Journal of Hydrology: Regional Studies
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2214581824005111
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author Mekonnen Gebremichael
Yu-Chuan Tien
Vahid Nourani
author_facet Mekonnen Gebremichael
Yu-Chuan Tien
Vahid Nourani
author_sort Mekonnen Gebremichael
collection DOAJ
description Study region: The Blue Nile basin, including the Grand Ethiopian Renaissance Dam (GERD) Study focus: This study evaluates the performance of seasonal precipitation forecasts from the North American Multi-Model Ensemble (NMME) over the Blue Nile Basin and compares them to newly developed statistical forecasting models, using the satellite-based Integrated Multi-satellitE Retrievals for GPM (IMERG) as the reference product. New hydrological insights for the region: The NMME models exhibit considerable variability in bias. Some models significantly overestimate precipitation across the years, others show substantial underestimation, some indicate minimal bias across most years, and a few demonstrate generally low bias with large outlier biases in specific years. Depending on the model, NMME can explain only from 2 % to 24 % of the summer precipitation variability. A simple statistical model, which uses June-July-August forecasts and Indian Dipole Mode Index (DMI) observations from the prior September-October-November as predictors, outperforms the dynamic NMME models in many performance metrics. Both the NMME models and the statistical model possess some skill in forecasting dry or wet summers, explaining up to 40 % of the temporal precipitation variability. This study underscores the need for further enhancing the accuracy of seasonal precipitation forecasting models to make the forecasts useful for applications
format Article
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institution Kabale University
issn 2214-5818
language English
publishDate 2025-02-01
publisher Elsevier
record_format Article
series Journal of Hydrology: Regional Studies
spelling doaj-art-14ed199675604842b3702f75f860bd302025-01-22T05:42:16ZengElsevierJournal of Hydrology: Regional Studies2214-58182025-02-0157102162Comprehensive evaluation of seasonal forecasts from NMME and statistical models over the Blue Nile Basin and the Grand Ethiopian Renaissance Dam (GERD) watershedMekonnen Gebremichael0Yu-Chuan Tien1Vahid Nourani2University of California, Los Angeles, USA; Correspondence to: UCLA Civil and Environmental Engineering, 420 Westwood Plaza, 5731 Boelter Hall, Los Angeles, CA 900951, USA.University of California, Los Angeles, USAUniversity of Tabriz, East Azerbayjan, Iran; Faculty of Civil and Environmental Eng., Near East University, TurkeyStudy region: The Blue Nile basin, including the Grand Ethiopian Renaissance Dam (GERD) Study focus: This study evaluates the performance of seasonal precipitation forecasts from the North American Multi-Model Ensemble (NMME) over the Blue Nile Basin and compares them to newly developed statistical forecasting models, using the satellite-based Integrated Multi-satellitE Retrievals for GPM (IMERG) as the reference product. New hydrological insights for the region: The NMME models exhibit considerable variability in bias. Some models significantly overestimate precipitation across the years, others show substantial underestimation, some indicate minimal bias across most years, and a few demonstrate generally low bias with large outlier biases in specific years. Depending on the model, NMME can explain only from 2 % to 24 % of the summer precipitation variability. A simple statistical model, which uses June-July-August forecasts and Indian Dipole Mode Index (DMI) observations from the prior September-October-November as predictors, outperforms the dynamic NMME models in many performance metrics. Both the NMME models and the statistical model possess some skill in forecasting dry or wet summers, explaining up to 40 % of the temporal precipitation variability. This study underscores the need for further enhancing the accuracy of seasonal precipitation forecasting models to make the forecasts useful for applicationshttp://www.sciencedirect.com/science/article/pii/S2214581824005111Seasonal precipitation forecastNMMEStatistical modelForecast evaluationGERDBlue Nile
spellingShingle Mekonnen Gebremichael
Yu-Chuan Tien
Vahid Nourani
Comprehensive evaluation of seasonal forecasts from NMME and statistical models over the Blue Nile Basin and the Grand Ethiopian Renaissance Dam (GERD) watershed
Journal of Hydrology: Regional Studies
Seasonal precipitation forecast
NMME
Statistical model
Forecast evaluation
GERD
Blue Nile
title Comprehensive evaluation of seasonal forecasts from NMME and statistical models over the Blue Nile Basin and the Grand Ethiopian Renaissance Dam (GERD) watershed
title_full Comprehensive evaluation of seasonal forecasts from NMME and statistical models over the Blue Nile Basin and the Grand Ethiopian Renaissance Dam (GERD) watershed
title_fullStr Comprehensive evaluation of seasonal forecasts from NMME and statistical models over the Blue Nile Basin and the Grand Ethiopian Renaissance Dam (GERD) watershed
title_full_unstemmed Comprehensive evaluation of seasonal forecasts from NMME and statistical models over the Blue Nile Basin and the Grand Ethiopian Renaissance Dam (GERD) watershed
title_short Comprehensive evaluation of seasonal forecasts from NMME and statistical models over the Blue Nile Basin and the Grand Ethiopian Renaissance Dam (GERD) watershed
title_sort comprehensive evaluation of seasonal forecasts from nmme and statistical models over the blue nile basin and the grand ethiopian renaissance dam gerd watershed
topic Seasonal precipitation forecast
NMME
Statistical model
Forecast evaluation
GERD
Blue Nile
url http://www.sciencedirect.com/science/article/pii/S2214581824005111
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AT yuchuantien comprehensiveevaluationofseasonalforecastsfromnmmeandstatisticalmodelsoverthebluenilebasinandthegrandethiopianrenaissancedamgerdwatershed
AT vahidnourani comprehensiveevaluationofseasonalforecastsfromnmmeandstatisticalmodelsoverthebluenilebasinandthegrandethiopianrenaissancedamgerdwatershed