EVALUATION OF SATELLITE-DERIVED HIGH RESOLUTION RAINFALL ESTIMATES OVER EASTERN SÃO PAULO AND PARANÁ,, BRAZIL

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1 EVALUATION OF SATELLITE-DERIVED HIGH RESOLUTION RAINFALL ESTIMATES OVER EASTERN SÃO PAULO AND PARANÁ,, BRAZIL Augusto J. Pereira Filho 1 Phillip Arkin 2 Joe Turk 3 John E. Janowiak 4 Cesar Beneti 5 Leonardo Calvetti 5 Ricardo Hallak 1 Felipe Vemado 1 1 DAC/IAG, University of São Paulo, Brazil 2 ESSIC, University of Maryland, College Park, USA 3 NRL, Marine Meteorology Division, USA 4 Climate Prediction Center/NOAA, USA 5 SIMEPAR, Paraná, Brazil PEHRPP Wokshop, Geneve,, Switzerland December, 2007

2 Paraná São Paulo

3 Background PEHRPP Wokshop, Geneve, Switzerland December, 2007

4 HOURLY ACCUMULATION 2003 and 2004 (Pereira Filho et al., 2006) (mm) PEHRPP Wokshop, Geneve, Switzerland December, 2007

5 TIME OF MAXIMUM RAINFALL 2003 and 2004 (UTC) (Pereira Filho et al., 2006) (mm) PEHRPP Wokshop, Geneve, Switzerland December, 2007

6 RADAR X SATELLITE Total Rainfall (Pereira Filho et al., 2002) 1 = Ground Clutter Filtering (2 and 3) 4 = Grind Clutter Contamination 5 = Range Effect 7 = Signal Processing 3 rd INTERNATIONAL PRECIPITATION WORKING GROUP WORKSHOP October 2006, Melbourne, Australia

7 Program for the Evaluation of High Resolution Precipitation Products (PEHRPP) coordinated by ESSIC and NRL. Goal is to compare and to validate these high resolution datasets. PEHRPP Wokshop, Geneve, Switzerland December, 2007

8 False alarms Estimated Hits Misses Observed Estimated Contingency Table yes no yes hits misses Observed no false alarms correct negatives (Elbert, 2003)

9 Probability of detection POD = hits hits + misses False alarm ratio FAR = false alarms hits + false alarms Bias score BIAS = hits + false alarms hits + misses Critical success index CSI = hits hits + misses + false alarms Root mean square error N 1 RMSE= ( E i Oi ) N i = 1 2 Correlation coefficient ρ = ( E ( E E) ( O O) E) 2 ( O O) 2

10 SPWR RAINFALL ESTIMATES (m) X CMORPH, TRMM, PERSIANN and NRL- BLENDED São Paulo, Brazil. Workshop on the EHRPP Geneve, Switzerland, December, 2007

11 SPWR DATASETS: 10/2005 TO 03/2006; SATELLITE PRECIPITATION DATA: 0.25 DEGREE X 3-HOUR; SYSTEM TYPES: COLD FRONT, RAIN BANDS, ORDINARY CONVECTION, SQUALL LINES PEHRPP Wokshop, Geneve, Switzerland December, 2007

12 EXAMPLES PEHRPP Wokshop, Geneve, Switzerland December, 2007

13 COLD FRONT Workshop on the EHRPP Geneve, Switzerland, December, 2007

14 RAIN BANDS PEHRPP Wokshop, Geneve, Switzerland December, 2007

15 ORDINARY CONVECTION 3 rd INTERNATIONAL PRECIPITATION WORKING GROUP WORKSHOP October 2006, Melbourne, Australia

16 0,2 OVERALL RESULTS All data sets available 10/05 to 03/06 0,1 mm 0,15 Mean CSI 0,1 0,2 mm 1,0 mm 4,0 mm 0,05 TRMM CMORPH PERSIANN NRL-B PEHRPP Wokshop, Geneve, Switzerland December, 2007

17 DISCUSSION (SP) Coordinate discrepancies; Phase and amplitude errors; All four methods yielded poor results; Radar rainfall accumulation higher than satellite ones; Radar data with range effect and other problems; Best performance for low rainfall accumulation: CMORPH; Best performance for higher accumulation: PERSIANN; Fewer data for PERSIANN; All methods are limited; Need for rain gauges and stream gauges verification. PEHRPP Wokshop, Geneve, Switzerland December, 2007

18 PARANA STATE Satellite techniques: CMORPH (Joyce et. al., 2004), PERSIANN (Sorooshian et al., 2000), TRMM (Huffman et. al., 1997), NRLB (Turk et. al., 2003) and CST (Adler e Negri, 1998). Data Methodology 141 weather stations over Parana State 1) Observed and estimated 0.25 spatial resolution over 56 W W and 27 S S for 1 day to a month accumulation. 2)Period: January 2003 December )Rain/non-rain threshold: 0.3mm/day and 20mm/month; 4)Statistics: average, variance, bias, POD FAR, ETS, MSE, correlation coefficient; 5)Hovmoller diagrams. PEHRPP Wokshop, Geneve, Switzerland December, 2007

19 Hovmöller Diagrams GAUGE CMORPH TRMM mm/month mm/month mm/month PERSIANN NRLB CST mm/month mm/month mm/month

20 Monthly Accumulation GAUGE October 2005 NRLB CST mm/month NRLB CST BIAS POD FAR COR RMSE GAUGE AVE SAT AVE GAUGE VAR SAT VAR Observed mm/month NRLB rain non-rain rain non-rain 1 0 Observed CST rain non-rain rain non-rain 0 0 Estimated Estimated mm/month Observed TRMM rain non-rain rain non-rain 28 0 Estimated GAUGE May 2005 TRMM TRMM BIAS 0.95 POD 0.95 FAR 0.00 COR 0.79 RMSE GAUGE AVE SAT AVE GAUGE VAR SAT VAR mm/month mm/month

21 Monthly Accumulations - Spatial BIAS (Jan/ Dec/2005)

22 Daily Accumulation November 17th, 2003 CMORPH BIAS 1.05 POD 0.99 FAR 0.05 COR 0.64 RMSE GAUGE AVE SAT AVE GAUGE VAR SAT VAR 8.59 Observed CMORPH rain non-rain rain non-rain 3 0 Estimated May 12th, 2004 TRMM BIAS 0.99 POD 0.96 FAR 0.03 COR 0.75 RMSE GAUGE AVE SAT AVE GAUGE VAR SAT VAR Observed TRMM rain non-rain rain non-rain Estimated

23 Discussion (PR) Hovmöller diagrams indicate good agreement between satellite-derived estimates and gauges, though amplitude differences are significant. Monthly satellite-derived accumulations better for January, May and October. Daily values highly variable. PEHRPP Wokshop, Geneve, Switzerland December, 2007

24 Polarimetric Data Sets 3 rd INTERNATIONAL PRECIPITATION WORKING GROUP WORKSHOP October 2006, Melbourne, Australia

25 Mobile Weather Radar Doppler Dual X-band (MXPOL) Hydrometeorology Lab (LabHidro) Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG), University of São Paulo.

26 Z h V r W ρo hv K dp MXPOL 4,5 o PPI at 2119 UTC on 26 April 2007.

27 São Paulo City sounding (83779) at 1200 UTC on 22 May SPWR 3-km CAPPI 1-km x 1-km resolution at 1616 UTC on 22 May MXPOL at (23 o 33.4 S; 46 o 44.1 W).

28 Vertical profile - Z h Vertical profile - V r Vertical profile - W MXPOL vertical profiles at 1616 UTC on 22 May Full clockwise antenna scan (6.0 o s o, pulse width = 0.2 μs, PRF=1000 Hz and 256 samples, Δz=35m.

29 Vertical profile - Z dr Vertical profile - φ dp Vertical profile - K dp Vertical profile - ρo hv MXPOL vertical profiles at 1616 UTC on 22 May Full clockwise antenna scan (6.0 o s o, pulse width = 0.2 μs, PRF=1000 Hz and 256 samples, Δz=35m.

30 Work supported by: FAPESP and CNPq (BRAZIL) NCAR and ESSIC (USA) WMO THE END PEHRPP Wokshop, Geneve,, Switzerland December, 2007