An integrated methodology for post-processing ensemble prediction systems to produce more representative extreme water level forecasts: the case of the Río de la Plata estuary

Matías G. Dinápoli () and Claudia G. Simionato
Additional contact information
Matías G. Dinápoli: Universidad de Buenos Aires
Claudia G. Simionato: Universidad de Buenos Aires

Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards, 2022, vol. 114, issue 3, No 22, 2927-2940

Abstract: Abstract The effects of weather extreme events can pose a threat to life and property, which is why proper prediction systems take on superlative importance. Despite the significant scientific advances in the field during the last decades, due to the intrinsic imperfections of prediction systems there will always be unavoidable uncertainties. To deal with them, deterministic prediction systems have been extended to “ensemble prediction systems” (EPS), defined as a composition of several simulations under different forcings, boundary conditions, parameters, models, etc., designed to represent the uncertainties. The mean of the EPS is often used for deterministic guidance to report the prediction but, in the presence of large differences among ensemble members, the average generates skewness that might underestimate the magnitude of the forecasts. In this paper, two techniques are revisited and readapted to improve the EPS forecasts. Firstly, it is proposed to partition ensemble forecasts into sub-ensemble forecasts, using cluster analysis to produce more representative predictions; this technique seeks to eliminate from the ensemble members which occurrence is considered unlikely. Secondly, it is suggested to associate to the ensemble forecast a complementary phase-aware ensemble (PAE) forecast, which computes the ensemble mean and spread separating the signal into carrier and modulated waves using the Hilbert transform. This integrated post-processing methodology was assessed with extreme storm surges that took place at the Río de la Plata estuary (Argentina) during this century with amplitudes exceeding $$\pm 2$$ ± 2 m (being the tidal range of about 0.75 m), for which the EPS presents large dispersion. Results show that, in the analyzed cases, the post-processing filters out the unlikely dynamical states, adjusts the mean ensemble to the observations and significantly reduces the uncertainty; the spread is reduced from 3 m to less than 1 m. The probability was also improved; for the analyzed cases, calibrated forecasts could anticipate peak events 4 days in advance with a relatively small uncertainty in both time and amplitude (one standard deviation). Additionally, the technique does not harm the forecast in cases when the dispersion between members of the ensemble is low. These results, together with the low computational cost of applying the technique, support incorporating our post-processing methodology as part of the EPS for storm surges, in which uncertainty is paramount for issuing warnings to face the effects of extreme weather events.

Keywords: Ensemble forecast; Probabilistic forecast; Río de la Plata estuary; Extreme surge forecast; Ensemble post-processing (search for similar items in EconPapers)
Date: 2022
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
http://link.springer.com/10.1007/s11069-022-05499-1 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:spr:nathaz:v:114:y:2022:i:3:d:10.1007_s11069-022-05499-1

Ordering information: This journal article can be ordered from
http://www.springer.com/economics/journal/11069

DOI: 10.1007/s11069-022-05499-1

Access Statistics for this article

Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards is currently edited by Thomas Glade, Tad S. Murty and Vladimír Schenk

More articles in Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards from Springer, International Society for the Prevention and Mitigation of Natural Hazards
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().