Gutenberg Open Science: Processes governing the amplification of ensemble spread in a medium-range forecast with large forecast uncertainty

Please use this identifier to cite or link to this item: http://doi.org/10.25358/openscience-7037

Full metadata record

DC Field	Value	Language
dc.contributor.author	Baumgart, Marlene	-
dc.contributor.author	Riemer, Michael	-
dc.date.accessioned	2022-05-25T09:21:49Z	-
dc.date.available	2022-05-25T09:21:49Z	-
dc.date.issued	2019	-
dc.identifier.uri	https://openscience.ub.uni-mainz.de/handle/20.500.12030/7051	-
dc.description.abstract	This study provides a process-based perspective on the amplification of forecast uncertainty and forecast errors in ensemble forecasts. A case from the North Atlantic Waveguide and Downstream Impact Experiment that exhibits large forecast uncertainty is analysed. Two aspects of the ensemble behaviour are considered: (a) the mean divergence of the ensemble members, indicating the general amplification of forecast uncertainty, and (b) the divergence of the best and worst members, indicating extremes in possible error-growth scenarios. To analyse the amplification of forecast uncertainty, a tendency equation for the ensemble variance of potential vorticity (PV) is derived and partitioned into the contributions from individual processes. The amplification of PV variance is, on average for the midlatitudes of the Northern Hemisphere, dominated by near-tropopause dynamics. Locally, however, other processes can dominate the variance amplification, for example, in the region where tropical storm Karl interacts with the Rossby-wave pattern during extratropical transition. In this region, the variance amplification is dominated by upper-tropospheric divergence and tropospheric–deep interaction and is thereby mostly related to (moist baroclinic) cyclone development. The differences between the error growth in the best and worst ensemble members can, to a large part, be attributed to differences in the representation of cut-off evolution around 3 days, which subsequently amplifies substantially in the highly nonlinear region of the Rossby-wave pattern until 5 days. In terms of the processes, the differences in error growth are dominated by differences in the error growth by near-tropopause dynamics. The approach presented provides flow-dependent insight into the dynamics of forecast uncertainty and forecast errors and helps to understand better the different contributions of specific weather systems to the medium-range amplification of ensemble spread.	en_GB
dc.language.iso	eng	de
dc.rights	CC BY	*
dc.rights.uri	https://creativecommons.org/licenses/by/4.0/	*
dc.subject.ddc	530 Physik	de_DE
dc.subject.ddc	530 Physics	en_GB
dc.title	Processes governing the amplification of ensemble spread in a medium-range forecast with large forecast uncertainty	en_GB
dc.type	Zeitschriftenaufsatz	de
dc.identifier.doi	http://doi.org/10.25358/openscience-7037	-
jgu.type.dinitype	article	en_GB
jgu.type.version	Published version	de
jgu.type.resource	Text	de
jgu.organisation.department	FB 08 Physik, Mathematik u. Informatik	de
jgu.organisation.number	7940	-
jgu.organisation.name	Johannes Gutenberg-Universität Mainz	-
jgu.rights.accessrights	openAccess	-
jgu.journal.title	Quarterly Journal of the Royal Meteorological Society	de
jgu.journal.volume	145	de
jgu.journal.issue	724	de
jgu.pages.start	3252	de
jgu.pages.end	3270	de
jgu.publisher.year	2019	-
jgu.publisher.name	Wiley	de
jgu.publisher.place	Weinheim	de
jgu.publisher.issn	1477-870X	de
jgu.organisation.place	Mainz	-
jgu.subject.ddccode	530	de
jgu.publisher.doi	10.1002/qj.3617	de
jgu.organisation.ror	https://ror.org/023b0x485
Appears in collections:	JGU-Publikationen

Files in This Item:

	File	Description	Size	Format
	processes_governing_the_ampli-20220525102510852.pdf		9.74 MB	Adobe PDF	View/Open

Show simple item record