Comparison between Singular Vectors and Breeding Vectors as Initial Perturbations for the ECMWF Ensemble Prediction System
2008 (English)In: Monthly Weather Review, ISSN 0027-0644, Vol. 136, no 11, 4092-4104 p.Article in journal (Refereed) Published
In this paper a study aimed at comparing the perturbation methodologies based on the singular vector ensemble prediction system (SV-EPS) and the breeding vector ensemble prediction system (BV-EPS) in the same model environment is presented. A simple breeding system (simple BV-EPS) as well as one with regional rescaling dependent on an estimate of the analysis error variance (masked BV-EPS) were used. The ECMWF Integrated Forecast System has been used and the three experiments are compared for 46 forecast cases between 1 December 2005 and 15 January 2006. By studying the distribution of the perturbation energy it was possible to see large differences between the experiments initially, but after 48 h the distributions have converged. Using probabilistic scores, these results show that SV-EPS has a somewhat better performance for the Northern Hemisphere compared to BV-EPS. For the Southern Hemisphere masked BV-EPS and SV-EPS yield almost equal results. For the tropics the masked breeding ensemble shows the best performance during the first 6 days. One reason for this is the current setup of the singular vector ensemble at ECMWF yielding in general very low initial perturbation amplitudes in the tropics.
Place, publisher, year, edition, pages
2008. Vol. 136, no 11, 4092-4104 p.
Meteorology and Atmospheric Sciences
IdentifiersURN: urn:nbn:se:su:diva-14998DOI: 10.1175/2008MWR2498.1ISI: 000260861900005OAI: oai:DiVA.org:su-14998DiVA: diva2:181518