Time-slice experiments

Transcription

1 Time-slice experiments Ulrich Cubasch Model & Data at the Max-Planck- Institut für Meteorologie with contributions by L. Bengtsson, W. May, J. Perlwitz, E. Roeckner, B. Timbal, R. Voss, J. Waszkewitz, M. Wild sponsored by several EU-projects, BMBF-projects

2 Content What are time-slice experiments? What experiments have been carried out? What are the results?

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4 No. Resolution Model Control 2*CO 2 3*CO 2 based on 1 T21L19 ECHAM3 30 years 30 years 30 years ECHAM1+ LSG transient experiments 2 T42L19 ECHAM3 30 years 30 years 30 years ECHAM1+ LSG transient experiments 3* T106L19 ECHAM3 5 years 5 years ECHAM1+LSG transient experiment 4 T106L19 ECHAM4 10 years climatological SST 5 T106L19 ECHAM4 10 years AMIP SST 6 T106L19 ECHAM4 10 years years ECHAM4/OPYC (IS 92a experiment Trend removed 7 T106L19 ECHAM4 30 years years ECHAM4/OPYC (IS 92a experiment 8 T42L30 IFS-ARPEGE (LMD) 9 T42L30 IFS-ARPEGE (LMD) 5 years 5 years ECHAM1+ LSG transient experiments 5 years Hadcm2 transient experiments Time-Slice Experiments

5 The grid cells representing Southern Europe for three different resolutions

6 The performance of the models in Southern Europe

7 The changes due to a doubling of the greenhouse gases

8 T21 T42 T106 DJF Temperature JJA The performance of the models and the changes for doubling of the greenhouse gases obs change T21 T42 T106

9 DJF Precipitation JJA T21 T42 T42 T106 The performance of the models and the changes for a doubling of the greenhouse gases obs change T21 T42 T106

10 The performance of the models (1) and the changes for a doubling of the greenhouse gases (2) Southern Europe

11 The performance of the models (1) and the changes for a doubling (2) and tripling (3) of the greenhouse gases. LMD: T42 Arpege model

12 The Greenland model topography for three resolutions

13 Greenland JJA temperature change for 2 different model versionsfor a doubling of greenhouse gases

14 Greenland annual ice accumulation change for 2 different model versions for a doubling of greenhouse gases

15 Changes in mass balance and sea level

16 MPI ECHAM3 MPI ECHAM3 HADCM2 Input Output The Arpege model driven by the SST derived from the MPI and the Hadley centre model simuations at greenhouse gas doubling

17 Timbal et al.: Sea surfac temperatures and doubled CO 2 MPI Hadley The Arpege model driven by the SST derived from the MPI and the Hadley centre model simuations at greenhouse gas doubling

18 MPI s SST HC s SST Fig. 8. Zonal mean precipitation anomalies obtained in summer (JJA) in MPIe (solid line) and Hce (dash line) The Arpege model driven by the SST derived from the MPI and the Hadley centre model simuations at greenhouse gas doubling

19 Summary - pro s Time-slice experiments are an easy way to obtain high resolution climate change data, also for driving regional and statistical models the results look more realistic, particularly in heterogenous terrain no problems with lateral boundary conditions exist equilibrium type simulations provide a good basis for a statistical analysis

20 Summary - contras the resolution is limited to about km the results are very dependent on underlying base experiment the lack of interaction with the ocean might distort the results

21 Summary - open questions the models employed have not really been tested and tuned for the high resolution there is no unique strategy how to run timeslice experiments the evaluation of the results is still very patchy due to the limited number of the experiments so far and due to the high volume of model output data