objective verification of cpc outlooks
DESCRIPTION
Objective Verification of CPC Outlooks. Michael Halpert Climate Prediction Center. Outline. Motivation Data Procedure Results Future Plans. Verification at CPC. Historically, CPC has verified ERF and LRF at first order stations. Forecasts made at 77 (out of 117) stations, 45 correct. - PowerPoint PPT PresentationTRANSCRIPT
Objective Verification of CPC Outlooks
Michael Halpert
Climate Prediction Center
Outline
• Motivation
• Data
• Procedure
• Results
• Future Plans
Verification at CPC
Historically, CPC has verified ERF and LRF at first order stations
Forecasts made at 77 (out of 117) stations, 45 correct.Heidke Skill Score = 37.7%
Monitoring Data Sets
Temperature• ~5000 stations/day: RFC,
HADS, CADB• 0.5 x 0.5 degree resolution• 20°- 60°N, 140° - 60°W,
Conus only• Mid – Midnight window• Daily Max + Min/2• SD Quality Control check Temperature Station Locations
Monitoring Temperature
90 Day Mean/Anomaly
Precipitation Station Locations
Monitoring Data Sets
Precipitation• ~8000 stations/day: RFC,
HADS, CADB, SNOTEL, Mexican data
• 0.25 x 0.25 deg resolution• 10°- 60°N, 140° - 60°W,
Conus/Mexico• 12Z – 12Z window• QC: SD, buddy, Duplicate,
Nexrad checks
Monitoring Precipitation
2° x 2° Grid
20° - 56°N, 130° - 60°W, 232 valid points
Temperature Analysis
Procedure
Calculate means and tercile limits for all 232 grid boxes based on 1971-2000 base period
Tercile limits calculated as 0.43 SD for temperature; 33rd and 67th percentile (based on gamma) for precipitation
January – March Temperature Difference (Upper – Lower)
Procedure
• Characterize seasonal mean temperature and total precipitation as above, near, or below average.
Procedure
• Compare verification field to forecast
DJF Verification Grid DJF Forecast Grid
Seasonal OutlookDec 2005 – Feb 2006
Seasonal OutlookDec 2005 – Feb 2006
Heidke = 77, Coverage = 73%
Heidke = 82, Coverage = 64%
All Non-EC % Cov 37.6 71.0 53.0
April – June 2006 Temperature
All Non-EC % Cov 27.6 48.1 57.3
April – June 2006 Temperature
Temperature Skill ScoresGridded vs. Stations ( non-EC)
Gridded Score – 23.7 Station Score – 24.2
All Non-EC % Cov 2.6 5.9 43.6
April – June 2006 Precipitation
All Non-EC % Cov 14.9 39.7 37.5
April – June 2006 Precipitation
June 2006 TOfficial, Update, Observations OBS
UPD0.5 Lead
Off. Up. ChangeAll Stations 18.4 33.3 +14.9 Non-EC: 56.6 65.0 +8.4 % Cov: 32.5 51.3 +18.8
Off. Up. ChangeAll Stations 18.8 25.4 +6.6 Non-EC: 48.3 43.1 -5.2% Cov: 38.8 59.1 +20.3
June 2006 TOfficial, Update, Observations
OBS
UPD
0.5 Lead
Gridded verification makes tool verification simple
JJA 2006 Temperature
JJA 2006 Temperature
Official – 60
Consolidation – 58.2
January – March 1998 Temperature
Official – 37.3
Consolidation – 51.5
Temperature Heidke Skill ScoresOfficial vs. Consolidation (non-EC)
Official – 23.7
Consolidation – 27.6
Temperature Heidke Skill ScoresOfficial vs. Consolidation (all)
Official – 11.4
Consolidation – 18.4
Precipitation Heidke Skill ScoresOfficial vs. Consolidation (non-EC)
Official – 5.3
Consolidation – 12.4
Precipitation Heidke Skill ScoresOfficial vs. Consolidation (all)
Official – 1.4
Consolidation – 3.1
Future Plans
Seasonal/monthly
• Verification of tools
• Ranked Probability Skill Score
• Conversion of tools to 2x2 grid
Future Plans
Extended Range
• Verification of forecasts
• Development of 5 and 7 day data sets
• Precipitation Complications
• Verification of tools
• RPSS
• Development of tercile limits