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This project evaluates the accuracy of quantitative precipitation forecasts using various data sources and verification indices. Monthly and daily data are analyzed for a two-year period.
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COSMO Priority Project ”Quantitative Precipitation Forecasts” Work in Task 1, Langen 8 March 2006 Katarzyna Starosta, Institute of Meteorology and Water Management, Poland
Used data and materials: 1. Bulletin of the national hydrological and meteorological service. (monthly) 2.Every day meteorological bulletin. 3.Every day LM model results (numerical data and maps with every 3 hour forecast, and cumulated precipitation forecast from 3h to 78h) 4.Every day precipitation data from 308 rain gauges stations. 5.Interpolated (bilinear interpolation) data from the model to rain gauges stations. 6.Results of monthly precipitation verification. 7.Difference between 24-precipitation sum in the rain gauges stations and model results.
LOCATION OF RAIN GAUGESTATIONS 50 45 40 35 30 25 20 15 10 5 0 0 10 20 30 40 50 The results of verification of24-h accumulated precipitation from January 2004 to December 2005are presented below. For precipitation we calculated indices from the contingency table for 24-h accumulated forecast data and data from 308 rain gauge stations for 3 day forecast range (1-day, 2-day, 3-day). For verification of precipitation thresholds 0.5, 1, 2.5, 5, 10, 20, 25, 30 mm were used. For each threshold the following scores were calculated: FBI (Frequency bias index), POD (Probability of detection of event), PON (Probability of detection of non-event) FAR (False alarm rate), TSS (True skill statistics), HSS (Heidke skill score), ETS (Equitable skill score).
THRESHOLD 0.5 [mm] 3 2.5 2 FBI 1.5 1 0.5 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 8 7 6 5 4 3 2 1 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC FREQUENCY BIAS INDEX, JANUARY - DECEMBER 2004 I day II day III day THRESHOLD 10[mm] FBI MONTHS
THRESHOLD 0.5 [ mm] 100 80 60 % 40 20 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 100 POD 80 PON 60 % FAR 40 HSS 20 ETS 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 100 80 60 40 20 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC INDICES FOR 24h ACCUMULATED PRECIPITATION, JANUARY - DECEMBER 2004 % MONTHS
THRESHOLD 10.0 [ mm] 100 80 60 % 40 20 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 100 POD 80 PON 60 % FAR 40 HSS 20 ETS 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 100 80 60 40 20 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC INDICES FOR 24h ACCUMULATED PRECIPITATION, JANUARY - DECEMBER 2004 I day II day % III day MONTHS
2004 • April 3 (for 6), 6,7,8 • May 7,8 • June 7(for 10), 19,20 • July 6-9, 27-29 • August 12 ,13,14, 17,18(Szczecin) , 19-22 • September 14,15,16 • October • November 4,5, 18 • December
2005 • January • February 12,15 • March 6,18 • April 8,9,10, 20 • May 3,4, 18,19, (23) • June (8),9,10,15,16 • July 7(Plock),9,10,26, 31 • August 3,4,7,8 15,16,23,24 • September 11,13,16,17 • October • November • December 6,7,15,16,20,30
Three forecast for the same day 23.08.05 Start of forecast: 21.08.05 00h 22.08.05 00h 23.08. 05 00h 3 h 6 h 9 h 12 h
Three forecast for the same day 23.08.05 Start of forecast: 21.08.05 00h 22.08.05 00h 23.08. 05 00h 15 h 18 h 21 h 24 h
Three forecast for the same day 24.08.05 Start of forecast: 21.08.05 00h 22.08.05 00h 23.08. 05 00h 03 h 06 h