Sara Liguori

Comparing quantitative precipitation forecast methods for prediction of sewer flows in a small urban area

Abstract Due to the relatively small spatial scale, as well as rapid response, of urban drainage systems, the use of quantitative rainfall forecasts for providing quantitative flow and depth predictions is a challenging task. Such predictions are important when consideration is given to urban pluvial flooding and receiving water quality, and it is worthwhile to investigate the potential for improved forecasting. In this study, three quantitative precipitation forecast methods of increasing complexity were compared and used to create quantitative forecasts of sewer flows 0–3 h ahead in the centre of a small town in the north of England. The HyRaTrac radar nowcast model was employed, as well as two different versions of the more complex STEPS model. The STEPS model was used as a deterministic nowcasting system, and was also blended with the Numerical Weather Prediction (NWP) model MM5 to investigate the potential of increasing forecast lead-times (LTs) using high-resolution NWP. Predictive LTs between 15 and 90 min gave acceptable results, but were a function of the event type. It was concluded that higher resolution rainfall estimation as well as nowcasts are needed for prediction of both local pluvial flooding and combined sewer overflow spill events. Editor D. Koutsoyiannis; Guest editor R.J. Moore Citation Schellart, A., Liguori, S., Krämer, S., Saul, A., and Rico-Ramirez, M.A., 2014. Comparing quantitative precipitation forecast methods for prediction of sewer flows in a small urban area. Hydrological Sciences Journal, 59 (7), 1418–1436. http://dx.doi.org/10.1080/02626667.2014.920505

A review of current approaches to radar-based quantitative precipitation forecasts

ABSTRACT Short-term radar-based forecasts of precipitation can be achieved through the implementation of nowcasting models, essentially based on the rainfall extrapolation from a series of consecutive radar scans. Recent advances in this field include the development of hybrid models, aimed at merging the benefits of radar nowcasting and numerical weather prediction models, and probabilistic systems, aimed at addressing the sources of uncertainty in radar rainfall forecasts by means of ensembles. This paper provides an overview of radar nowcasting methods and approaches, with an emphasis on recent developments in this field.