Miklip first phase: STRATO

The role of the stratosphere for decadal climate prediction

The project STRATO aims to study and evaluate the importance of the stratosphere for mid-term predictions of climate change. The focus is laid on the quantification of reactions of the coupled atmosphere-ocean system to decadal stratospheric variability. Recent analyses of observations and data from numerical model simulations show a clear impact of decadal stratospheric fluctuations on the troposphere. Therefore one can proceed from the assumption that a consideration of stratospheric processes will lead to improved decadal climate predictions. STRATO concentrates on investigations of the role of the decadal solar activity (i.e. the 11-year solar cycle, cf. Figure 1) and internal stratospheric variability on decadal time-scales and the subsequent tropospheric reactions (cf. Figures 2 and 3). 

STRATO - Fig. 1
Figure 1: Schematic diagram of solar influence on climate based on Kodera and Kuroda (2002). Shown are the direct and indirect effects through solar irradiance changes (TSI and UV) with respect to Smax as well as corpuscular radiation effects (energetic particles and GCRs). The two dashed ar-rows denote the coupling between the stratosphere and the troposphere and the coupling between the ocean and the atmosphere. (Figure from Gray et al., 2010)

STRATO provides quantitative statements for improvements of a numerical prediction model for mid-term climate change due to the consideration of stratospheric processes (module B). The expertise of STRATO is used for the evaluation of the reliability of mid-term climate forecasts, in particular regarding the role of the stratosphere and its variability on decadal time scales (module D). STRATO provides necessary data for the initialisation of stratospheric conditions needed in the new MiKlip-model system (module A). Data derived from numerical studies performed in STRATO are analysed; these data are provided to other MiKlip-groups, e.g. they can be used to test methods and techniques which are needed for downscaling smaller spatial structures in the upper troposphere and lower stratosphere (module C). Furthermore, STRATO provides quantitative information regarding uncertainties of recently used model systems of the upper troposphere and stratosphere (module E).

STRATO - Fig. 2
Figure 2: Schematic diagram indicating the role of different dynamical processes in the troposphere and stratosphere and the dynamical interactions between both layers. (Copyright 2000, Natl. Acad. Sci, U.S.A. Reproduced with permission.)

It is expected that results of the STRATO project will establish enhanced knowledge of the in-teractions between the stratosphere and the troposphere-ocean system, improving mid-term climate prediction. In particular, STRATO will improve the basic understanding of the impacts of decadal solar variability and internal stratospheric fluctuations on the atmosphere-ocean system on decadal time-scales. Based on investigations carried out in STRATO, recommendations to further develop the MiKlip-forecast system will be transfered to the respective team; appropriate software will be provided to improve the quality of climate prediction on decadal time-scales. STRATO aims to contribute to a better understanding of the Earth’s climate system, leading to a generally improved climate modelling.


  • Quantification of the influence of stratospheric solar forcing on decadal climate prediction.
  • Determination of the importance of stratospheric internal variability for decadal climate prediction.
  • Analysis and evaluation of the relevance of stratospheric decadal variability for the coupled atmosphere-ocean system.
STRATO - Fig. 3
Figure 3: Composites of time-height development of the northern annular mode for (A) 18 weak vor-tex events and (B) 30 strong vortex events. The events are determined by the dates on which the 10-hPa annular mode values cross -3.0 and 11.5, respectively. The indices are non dimensional; the con-tour interval for the color shading is 0.25, and 0.5 for the white contours. Values between 20.25 and 0.25 are unshaded. The thin horizontal lines indicate the approximate boundary between the tropo-sphere and the stratosphere. (Figure from Baldwin und Dunkerton, 2001)

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Freie Universität Berlin, Institut für Meteorologie
Prof. Dr. Ulrike Langematz

Institut für Physik der Atmosphäre, Deutsches Zentrum für Luft- und Raumfahrt
Prof. Dr. Martin Dameris