Benchmarking seasonal forecasting skill using river flow persistence in Irish catchments. Issue 4 (12th March 2021)

• Record Type: Journal Article
• Authors: Foran Quinn, Dáire; Murphy, Conor; Wilby, Robert L.; Matthews, Tom; Broderick, Ciaran; Golian, Saeed; Donegan, Seán; Harrigan, Shaun
• Is Part Of: Hydrological sciences journal. Volume 66:Issue 4(2021)
• Page Start: 672
• Page End: 688
• Publication Date: 2021-03-12
• Subjects: seasonal hydrological forecasting -- prediction -- persistence -- river flow -- Ireland; Hydrology -- Periodicals; 551.4805
• DOI: 10.1080/02626667.2021.1874612
• Languages: English
• ISSNs: 0262-6667

Abstract

ABSTRACT: This study assesses the seasonal forecast skill of river flow persistence in 46 catchments representing a range of hydrogeological conditions across Ireland. Skill is evaluated against a climatology benchmark forecast and by examining correlations between predicted and observed flow anomalies. Forecasts perform best when initialized in drier summer months, 87% of which show greater skill relative to the benchmark at a 1-month horizon. Such skill declines as forecast horizon increases due to the longer time a catchment has to "forget" initial anomalous flow conditions and/or to be impacted by "new" events. Skill is related to physical catchment descriptors such as the baseflow index (correlation ρ = 0.86) and is greatest in permeable high-storage catchments. The distinct seasonal and spatial variations in persistence skill allow us to pinpoint when and where this method can provide a useful benchmark in the future development of more complex seasonal hydrological forecasting approaches in Ireland.