Jens Grieger

Jens Grieger
Freie Universität Berlin | FUB · Institute of Meteorology

PhD

About

25
Publications
3,553
Reads
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589
Citations
Citations since 2016
14 Research Items
469 Citations
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
Additional affiliations
February 2009 - present
Freie Universität Berlin
Position
  • Research Associate
May 2005 - September 2007
Humboldt-Universität zu Berlin
Position
  • Research Assistant

Publications

Publications (25)
Article
Full-text available
The Antarctic Oscillation (AAO) is the dominant mode of atmospheric variability in the southern hemisphere. It is obtained via a principal component analysis (PCA) for geopotential height anomalies. Being the southern hemisphere's dominant mode, an adequate representation in earth system models is desirable. This paper evaluates to what extent the...
Article
Full-text available
In the early 1980s, Germany started a new era of modern Antarctic research. The Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) was founded and important research platforms such as the German permanent station in Antarctica, today called Neumayer III, and the research icebreaker Polarstern were installed. The research...
Article
This paper investigates climate change signals of Southern Hemisphere (SH) moisture flux simulated by three members of one CMIP3 coupled atmosphere-ocean general circulation model (AOGCM) and a multimodel ensemble of CMIP5 simulations. Generally, flux changes are dominated by increased atmospheric moisture due to temperature increase in the future...
Article
This article investigates extratropical winter cyclone activity in the Southern Hemisphere (SH) in a multi-model ensemble (MME) of coupled atmosphere–ocean general circulation model (AOGCM) simulations of recent and potential future climate conditions. Most individual models and also the ensemble mean yield good reproductions of the typical cyclone...
Article
Full-text available
The variability of results from different automated methods of detection and tracking of extratropical cyclones is assessed in order to identify uncertainties related to the choice of method. Fifteen international teams applied their own algorithms to the same dataset—the period 1989–2009 of interim European Centre for Medium-Range Weather Forecast...
Preprint
Full-text available
Wind and windstorms cause severe damage to natural and human-made environments. Thus, wind-related risk assessment is vital for the preparation and mitigation of calamities. However, the cascade of events leading to damage depends on many factors that are environment-specific and the available methods to address wind-related damage often require so...
Article
Full-text available
Near-term climate predictions such as multi-year to decadal forecasts are increasingly being used to guide adaptation measures and building of resilience. To ensure the utility of multi-member probabilistic predictions, inherent systematic errors of the prediction system must be corrected or at least reduced. In this context, decadal climate predic...
Article
Full-text available
Freva – Free Evaluation System Framework for Earth system modeling is an efficient solution to handle evaluation systems of research projects, institutes or universities in the climate community. It is a scientific software framework for high performance computing that provides all its available features both in a shell and web environment. The mai...
Article
Dekadische Klimavorhersagen füllen die Lücke zwischen saisonalen Klimavorhersagen und langzeitigen Klimaprojektionen und ermöglichen damit der Wirtschaft und dem öffentlichen Sektor die Entwicklung zukunftsfähiger Handlungsstrategien. MiKlip (Mittelfristige Klimaprognosen) war ein nationales, vom Bundesministerium für Bildung und Forschung geförder...
Preprint
Dekadische Klimavorhersagen füllen die Lücke zwischen saisonalen Klimavorhersagen und langzeitigen Klimaprojektionen und ermöglichen damit der Wirtschaft und dem öffentlichen Sektor die Entwicklung zukunftsfähiger Handlungsstrategien. MiKlip (Mittelfristige Klimaprognosen) war ein nationales, vom Bundesministerium für Bildung und Forschung geförder...
Preprint
Near-term climate predictions such as decadal climate forecasts are increasingly being used to guide adaptation measures. To ensure the applicability of these probabilistic predictions, inherent systematic errors of the prediction system must be corrected. In this context, decadal climate predictions have further characteristic features, such as th...
Article
Full-text available
In this study the latest version of the MiKlip decadal hindcast system is analyzed, and the effect of an increased horizontal and vertical resolution on the prediction skill of the extratropical winter circulation is assessed. Four different metrics – the storm track, blocking, cyclone and windstorm frequencies – are analyzed in the North Atlantic...
Article
Full-text available
The North Atlantic is a crucial region for the prediction of weather and climate of North America and Europe and is the focus of this analysis. A skillful decadal prediction of the surface temperature was shown for several Earth system models, with the North Atlantic standing out as one region with higher predictive skill. This skill assessment con...
Article
Full-text available
In this study the latest version of the MiKlip decadal hindcast system is analyzed and the effect of different horizontal and vertical resolutions on the prediction skill of the northern hemisphere extra-tropical atmospheric circulation is assessed. Four metrics – the stormtrack, blocking frequencies, cyclone frequencies and windstorm frequencies –...
Article
Full-text available
One of the most prominent asymmetric features of the southern hemispheric (SH) circulation is the split jet over Australia and New Zealand in austral winter. Previous studies have developed indices to detect the degree to which the upper-level midlatitude westerlies are split and investigated the relationship between split events and the low-freque...
Article
Full-text available
Extra-tropical cyclones in the subantarctic play a central role in the poleward transport of heat and moisture into Antarctica, with the latter being a key component of the mass balance of the Antarctic ice sheet. As the climate in this region undergoes substantial changes, it is anticipated that the character of these synoptic features will change...
Thesis
Full-text available
The Antarctic Ice Sheet is the largest single ice mass on earth. Future change of Antarctic surface mass balance potentially impacts global sea level. Therefore, investigations of future surface mass balance is highly relevant and also discussed by the "Intergovernmental Panel on Climate Change". While the role of future increase of atmospheric moi...
Article
Full-text available
For Northern Hemisphere extra-tropical cyclone activity, the dependency of a potential anthropogenic climate change signal on the identification method applied is analysed. This study investigates the impact of the used algorithm on the changing signal, not the robustness of the climate change signal itself. Using one single transient AOGCM simulat...
Conference Paper
This study investigates mechanisms leading to changes of net precipitation (E-P) over Antarctica and the Southern Ocean in a multi-model ensemble of coupled AOGCMs for a 21st century time period according to the IPCC SRES A1B scenario. Meridional moisture flux is divided into time-averaged and transient parts. The latter constitutes the main contri...
Conference Paper
The evolution of Antarctic climate during the past four decades was characterized by enhanced tropospheric westerlies and a negative trend in near-surface temperature over the Antarctic plateau during the austral summer, while the Antarctic Peninsula showed a warming (Thompson and Solomon, 2002). Model simulations suggested that these trends are mo...
Conference Paper
In the context of the IMILAST intercomparison project (Intercomparison of mid latitude storm diagnostics; http://www.proclim.ch/IMILAST/index.html), an analysis of mid-latitude cyclone characteristics deduced from ERA40 and ERAinterim data is presented. The analysis is based on the Murray and Simmonds cyclone identification and tracking algorithm....
Conference Paper
Full-text available
This study investigates Southern Hemisphere (SH) cyclone development around Antarctica and the Southern Ocean, the variability and extremes under present climate conditions and the possible shift in an anthropogenic changed climate. Therefore reanalysis data and the data of a multi-model ensemble are analysed by applying an objective cyclone identi...
Thesis
Die vorliegende Arbeit untersucht zwei "Open Source" Projekte für die Gitter-Quanten-Chromo-Dynamik (Gitter-QCD), und zwar das "Chroma Software Projekt" und die "Domain-Decomposition-Hybrid-Monte-Carlo (DD-HMC) Software". Ziel war, Informationen für die Anwendung der Programme aus der Sicht eines neuen Benutzers zu erhalten. Chroma kann für untersc...

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Projects

Projects (2)
Archived project
The overarching goal for MiKlip II is to establish and improve the decadal climate prediction system that eventually can be transferred to the German meteorological service DWD for operational use. Read more on the project website: www.fona-miklip.de and find a comprehensive list of publications here: http://www.fona-miklip.de/service/publications/
Project
Mittelfristige Klimaprognose (MiKlip) Module E is evaluating hindcasts from the MiKlip decadal prediction system focusing the main pillars: i) generation of observational data sets and their use for an improved validation of hindcasts, ii) hindcast verification, i.e. the development and implementation of procedures for a quantitative estimation of forecast quality, and iii) process-oriented validation to enhance the understanding and thus the credibility of the prediction system and its products. Working towards an operational system in MiKlip II, an additional focus comes up: the transfer of predictions from the MiKlip system into probabilistic forecast products for users. This implies a) bias correction of predictions taking a model drift and a climate trend into account, b) calibration of probabilistic forecasts to increase reliability, and c) the construction of forecasts for user-relevant quantities and events, such as heat-waves, droughts, storm surges or other kinds of large-scale climate anomalies. These pillars define five Module E objectives paving the way towards a useroriented operational system: 1. Bias and Drift correction, Calibration 2. User-oriented post-processing 3. Process-oriented validation 4. Generation of data sets 5. Hindcast verification http://www.fona-miklip.de/research/miklip-ii-miklip-second-phase/module-e-evaluation/