1. 1 First results and methodological approach to parameter perturbations in GEM-LAM simulations PART II Leo Separovic, Ramon de Elia and Rene Laprise

2. 2 Reduction of domain size 140x140 70x92 100x100 ~5500km 30x52 Integral Core only 5515 58 Core of the small domain and the common region used to compute grid statistics in the following

3. 3 GZ850 DJF MMAJJASON DJFMMAJJASON P - P + LargeSmall Statistical significance: RMS (t) over the small-domain core area (-) wklcl=0.020, (+) wklcl=0.048

4. 4 GZ850 Error P - P + DJFMMAJJASON DJFMMAJJASON LargeSmall Error magnitude: 2xRMS standard deviation of the ensemble average Signal magnitude: RMSD between reference and perturbed-parameter ensemble averages; (-) wklcl=0.020, (+) wklcl=0.048

5. 5 90.0 95.0 97.5 99.0 99.5 99.9 99.5 99.0 97.5 95.0 90.0 GZ850: WKLCL(-), JJA Internal variability signal S L S L SL Rejection level for H0 %

6. 6 PCP DJF MMAJJASON DJFMMAJJASON P - P + LargeSmall Statistical significance: RMS (t) over the small-domain core area (-) wklcl=0.020, (+) wklcl=0.048

7. 7 PCP DJF MMAJJASON DJFMMAJJASON Error P - P + LargeSmall Error magnitude: 2 x RMS standard deviation of the ensemble average Signal magnitude: RMSD between reference and perturbed-parameter ensemble averages; (-) wklcl=0.020, (+) wklcl=0.048

8. 8 90.0 95.0 97.5 99.0 99.5 99.9 99.5 99.0 97.5 95.0 90.0 PCP: WKLCL(+), JJA Internal variability signal S L S L SL Rejection level for H0 %

9. 9 TTscn DJF MMAJJASON DJFMMAJJASON P - P + LargeSmall Statistical significance: RMS (t) over the small-domain core area (-) wklcl=0.020, (+) wklcl=0.048

10. 10 TTscn DJF MMAJJASON DJFMMAJJASON Error P - P + K LargeSmall Error magnitude: 2 x RMS standard deviation of the ensemble average Signal magnitude: RMSD between reference and perturbed-parameter ensemble averages; (-) wklcl=0.020, (+) wklcl=0.048

11. 11 90.0 95.0 97.5 99.0 99.5 99.9 99.5 99.0 97.5 95.0 90.0 TTscn: WKLCL(-), JJA Internal variability signal L S L S L SL Rejection level for H0 %

12. 12 Future work Add an intermediate domain; Repeat the study for singleton perturbations of the threshold relative humidity for the onset of precipitation; Study synchronous perturbations of the two parameters; (Non)linearity of the model response to multiple perturbations and domain size. Alexandru et al. (2007)