1. Analysis of Daily Rainfall from a Nested Modeling System for South America Anji Seth International Research Institute for Climate Prediction Maisa Rojas, University of Chile Brant Liebmann, NOAA CDC Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003

2. Outline Climatology of daily rainfall (V. Kousky, CPC) Spatial Characteristics Observed Daily Rainfall: FMAM 1983, 1985 Simulated Daily Rainfall: FMAM 1983, 1985 Temporal characteristics Observed Daily Rainfall: FMAM 1983, 1985 Simulated Daily Rainfall: FMAM 1983, 1985 Sensitivity: Local Forcing,Domain Effects Preliminary Conclusions

3. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 V. Kousky, CPC Climatology (1979-1995) Computed for Brazil Typical station coverage

4. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Annual Rainfall Frequency (>1mm) % days/year V. Kousky, CPC

5. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Frequency (>1mm) % days/month V. Kousky, CPC Central and Southeast: >85% (summer) <25% (winter) Northwest: >75% year round Northeast: >65% (jan-may) <15% (jun-dec)

6. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Frequency (>10 mm) % days/month Peak frequencies in The northwest drop to 50% V. Kousky, CPC

7. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Frequency (>25 mm) % days/month Peak frequencies in The northwest drop to 10% (summer months) Southern Brazil has Heavy rainfall events year round V. Kousky, CPC

8. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Station Coverage for Observed Daily Rainfall B. Liebmann, CDC 1983 1985

9. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Rainfall Frequency (>1 mm) % days/JFMAM 1983 1985

10. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Rainfall Frequency (>10 mm) % days/JFMAM 1983 1985

11. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Rainfall Frequency (>25 mm) % days/JFMAM 1983 1985

12. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 RegCM2 (Giorgi et al., 1993) 110x145x14 60 km resolution Remote: Reanalyses 83,85 CCM3(x3) 83,85 Local: deforestation

13. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Observed RegCM Frequency >1 mm 19851983

14. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Observed RegCM Frequency >10 mm 1985 1983

15. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Observed RegCM Frequency >25 mm 19851983

16. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Observed Daily Rainfall, 1983 1985

17. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Observed Rainfall Frequency 1983 1985

18. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Simulated, Observed Daily Rainfall 1983 1985

19. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Simulated, Observed Daily Rainfall 1983 1985

20. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Simulated*, Observed Daily Rainfall 1983 1985 *GCM>RegCM

21. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Simulated*, Observed Daily Rainfall 1983 1985 *GCM>RegCM

22. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 ST/RR/GR1/GR2/GR3 Observed, Simulated Rainfall Frequency 1983 1985

23. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 ST/RR/GR1/GR2/GR3 Observed, Simulated Rainfall Frequency 1983 1985

24. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 ST/RR/GR1/GR2/GR3 Observed, Simulated Rainfall Frequency 1983 1985

25. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003 Preliminary Conclusions Spatial Characteristics – using thresholds of 1,10,and 25 mm Observed Daily Rainfall frequencies were notable higher in 1985 than 1983 in Nordeste and the Amazon. Simulated Daily Rainfall reproduced the observed patterns in the two years remarkably well. Temporal characteristics – time series and frequency distributions showed Observed Daily Rainfall was deficient throughout the 1983 season in Nordeste and early in the season in the Amazon. Simulated Daily Rainfall captured the observed frequency distributions well in the reanalyses> RegCM

26. Workshop on Theory and Use of Regional Climate Models ICTP, Trieste June 2003