laurence wilson associate scientist emeritus environment canada monica bailey, marcel vallee and...
TRANSCRIPT
Laurence WilsonAssociate Scientist Emeritus
Environment Canada
Monica Bailey, Marcel Vallee and Ivan Heckmann
Verification of forecasts from the 2010 Verification of forecasts from the 2010 Vancouver Olympic GamesVancouver Olympic Games
Outline
Data Available Observations Forecasts
Verification plan Preliminary Results Future
Observing sites in the vicinity of Whistler
-supplementary obs sites (VOA, VOL etc)
-extra in situ instrumentation
-radars
-profilers
“Standard” stations for verification
Forecasts• GEM-15 km regional model• 2.5 km LAM using bc from regional model• 1 km LAM nested in 2.5 km model• No data assimilation for LAMs• Several nowcast and post-processing systems:
– Adaptive blending of observations and models (ABOM), INTW– CMA, ZAMG-INCA, NCAR-WSDDM
• Limited UMOS for Olympic sites• Operational forecasts for Olympic venues
15 km
1 km
2.5 km
WhistlerWhistler
VancouverVancouver
Snowboard Men’s Parallel Giant Slalom Final February 27, 2010
Gold Medal to Jassey Jay Anderson of Canada
Snowboard spectators stand in the fog during the men's Parallel Giant Slalom snowboarding competition at the Vancouver 2010 Olympics in Vancouver, British Columbia, Saturday, Feb. 27, 2010. (AP Photo/Bela Szandelszky)
Visibility forecasts and obs before mens giant snowboard slalom finals
Snow- V 10 Verification plan
At least two classes of users: Olympics forecasting team – VANOC
“How accurate are forecasts of weather events significant to VANOC?” “Should the forecasters have used the nowcast products?”
Modelers “Are forecasts from the 2.5 km LAM an improvement on the 15km
regional forecasts?” “Are there any advantages to the 1 km grid?”
Two Parts: user-oriented verification for Olympic period of all forecasts,
tuned to decision points of VANOC Verification of parallel model forecasts for Jan to August 2010
Rich dataset for user-oriented verification and research: multiple observations at some sites, allows for estimates of observation error
Verification strategy User-specified thresholds –
categorical/contingency tables Only surface-defined variables
For user-oriented verification: Wind, precipitation amount and type, visibility, wind gusts,
cloud base height, temperature, humidity High temporal resolution – 15 minutes 0-2h, hourly after that During Olympics period only « representative » point selected in advance by forecasters
For Model verification: Temperature, precipitation, wind, cloud amount, and possibly
ceiling and visibility From all stations in model domain 6 months period At stations, categorical and continuous verification
Variable Category 1 Category 2 Category 3 Category 4 Category 5 Category 6 Category 7 Category 8 Category 9Temperature -25 C < -25≤ T<-20C -20≤ T<-4C -4≤ T<-2C -2≤ T< 0C 0≤ T< +2C +2 ≤ T< +4C ≥ +4C
RH < 30% 30≤ RH< 65% 65≤ RH< 90% 90≤ RH< 94% 94≤ RH< 98% ≥ 98% Winds < 3 m/s 3 ≤ w < 4
m/s4 ≤ w < 5
m/s5 ≤ w < 7
m/s7 ≤ w < 11
m/s11 ≤ w < 13
m/s13 ≤ w < 15
m/s15 ≤ w < 17
m/s≥ 17m/s
Wind Gust < 3 m/s 3 ≤ w < 4 m/s
4 ≤ w < 5 m/s
5 ≤ w < 7 m/s
7 ≤ w < 11 m/s
11 ≤ w < 13 m/s
13 ≤ w < 15 m/s
15 ≤ w < 17 m/s
≥ 17m/s
Wind Direction
d ≥ 339 & d < 24º (N)
24 ≤ d < 69º (NE)
69 ≤ d < 114º (E)
114 ≤ d < 159º (SE)
159 ≤ d < 204º (S)
204 ≤ d < 249º (SW)
249 ≤ d < 294º (W)
294 ≤ d < 339º (NW)
Visibility v < 30m 30 ≤ v < 50m
50 ≤ v < 200m
200 ≤ v < 300m
300 ≤ v < 500m
≥ 500m - -
Ceiling c < 50m 50 ≤ c< 120 m
120 ≤ c< 300 m
300 ≤ c< 750 m
750 ≤ c< 3000 m
c ≥ 3000 m - - -
Precip Rate r = 0 mm/hr (None)
0 < r ≤ 0.2 mm/hr (Trace)
0.2 < r ≤ 2.5 mm/hr (Light)
2.5 < r ≤ 7.5 mm/hr
(Moderate)
r > 7.5 mm/hr
(Heavy)
- - - -
Precip Type No Precip Liquid Freezing Frozen Mixed (w/Liquid)
Unknown - - -
Table 5 (2nd Revised Suggestion for SNOW-V10 Verification)
Suggested Categories for SNOW-V10 Analysis
Standardized forecast table for Vancouver Olympics
Preliminary Comparison of Sport Forecast with Canadian Models for Top of Downhill (VOA), Mid-Station (VOL) and Timing Flats (VOT)
Wind Direction
Bias for temperature forecasts
RMSE, T2m, 6 mo, all stns in model domain
Future
Finish verification according to plan based on “standard” data
Special journal issue planned Comparison with operational forecasts Verification using “special” data
Higher temporal resolution Research studies:
Estimating observation error Model diagnostic studies