Draft Water Resources Management Plan 2019 Annex 3: Supply forecast Appendix B: calibration of the synthetic weather generator November 30, 2017 Version 1
Introduction This appendix contains calibration plots for the synthetic weather generator that compare the distribution of observed rainfall over various accumulation intervals to the range of the synthetic rainfall data. To demonstrate the calibration of the weather generator outputs against the historical climate a series of Quantile-Quantile (Q-Q) plots have been produced. A quantile-quantile plot compares ranked outputs from the model against the equivalent rank of the observed data sets. For example, the rainfall total for fifth driest simulated year would be plotted against the fifth driest observed year. The grey points show the range and variability of the synthetic weather simulations for 500 different realisations of equal length to the historic record. The solid red dots indicate the mean of that range. If the weather generator simulated the historic climate distribution exactly, then all of the data would plot on the 1:1 line. However, the point of this modelling is not to exactly reproduce the historic climate, but to stochastically simulate alternative, but plausible climate sequences. For a reasonable calibration the pattern of the scatter include the 1:1 line but with a reasonable degree of variability about this line. Generally a roughly even scatter about the 1:1 line across the whole data range would be desirable as this would demonstrate the model is not systematically drier or wetter than observations, especially at either tail of the dataset. To examine the model calibration, rainfall totals are compared over a number of different accumulation periods; 6, 12, 18, 24, 30, 48 and 60 Month rainfall accumulations for months ending in October, November and December. These plots are produced as a single set for each aggregation period across the whole of the rainfall dataset. 2 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 1 Calibration Plots (6-month ending December) 3 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 2 Calibration Plots (6-month ending November) 4 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 3 Calibration Plots (6-month ending October) 5 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 4 Calibration Plots (12-month ending December) 6 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 5 Calibration Plots (12-month ending November) 7 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 6 Calibration Plots (12-month ending October) 8 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 7 Calibration Plots (18-month ending December) 9 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 8 Calibration Plots (18-month ending November) 10 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 9 Calibration Plots (18-month ending October) 11 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 10 Calibration Plots (24-month ending December) 12 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 11 Calibration Plots (24-month ending November) 13 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 12 Calibration Plots (24-month ending October 14 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 13 Calibration Plots (30-month ending December) 15 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 14 Calibration Plots (30-month ending November) 16 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 15 Calibration Plots (30-month ending October) 17 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 16 Calibration Plots (36-month ending December) 18 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 17 Calibration Plots (36-month ending November) 19 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 18 Calibration Plots (36-months ending October) 20 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 19 Calibration Plots (48-month ending December) 21 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 20 Calibration Plots (48-month ending November) 22 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 21 Calibration Plots (48-month ending October) 23 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 22 Calibration Plots (60-month ending December) 24 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 23 Calibration Plots (60-month ending November) 25 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator
Figure 24 Calibration Plots (60-month ending October) 26 Draft Water Resources Management Plan 2019 Annex 3: Appendix B: Calibration of the synthetic weather generator