How sensitive are probabilistic precipitation forecasts to the choice of ensemble generation method?

RUIZ, J.; SAULO, C.

Nanjing

Congreso; 3rd International Conference on QPE, QPF and Hydrology; 2010

Organización Meteorológica Mundial

In this work the sensitivity of summer Probabilistic Quantitative PrecipitationForecasts (PQPF) over South Eastern South America to alternative ensemblegeneration methods is examined. Three ensemble systems and combinationsbetween them were used to generate calibrated PQPF over the selected regionand the results were evaluated using the Brier Skill Score. Results show thatcalibrated PQPF quality exhibits sensitivity to the ensemble system used andthis sensitivity is mainly related with the resolution component of the Brier SkillScore. A multimodel approach shows the best results for 24 and 48- hour leadtimes. The use of a spatial shift technique to increase ensemble size has alsobeen evaluated. This technique improves the skill of PQPF when combined withmultimodel ensemble at all lead times.