egows 2008 the beijing 2008 nowcasting forecast demonstration project
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EGOWS 2008 The Beijing 2008 Nowcasting Forecast Demonstration Project. John Bally CAWCR. Beijing ‘08. WMO >> WWRP >> FDP Implement nowcasting science and systems for the Olympics Provide an enhanced weather service Technology transfer and training Quantify the benefits. Olympics. - PowerPoint PPT PresentationTRANSCRIPT
EGOWS 2008
The Beijing 2008 Nowcasting Forecast Demonstration Project
John BallyCAWCR
Beijing ‘08
• WMO >> WWRP >> FDP
• Implement nowcasting science and systems for the Olympics
• Provide an enhanced weather service
• Technology transfer and training
• Quantify the benefits
Beijing ‘08 Daily probability of rainfall in Beijing from August 1 to September 30
Olympics Paralympics
Beijing ‘08 Vulnerabilities
Beijing ‘08 Enhanced data collection.....
Beijing ‘08 Many systems will be in Beijing...
BJANC (BMB&NCAR)
CARDS (MSC)
GRAPES-SWIFT (CMA)
MAPLE (McGill & WDT),
NIWOT (NCAR)
STEPS (CAWCR)
SWIRLS (HKO)
TIFS (CAWCR)
Real Time Verification (CAWCR)
Socio Economic Impacts Assessment
(BMB)
Beijing ‘08 Many Systems will be in Beijing.....
Beijing ‘08 How will we use so many systems?
Beijing ‘08Which system is best ?
Real Time Forecast Verification
every 6 minutes
Beijing ‘08 Web Page display for forecasters
Beijing ‘08 Concentrate on some big risks….
High Impact Weather
Observed Frequency
Precipitation 35 %
Thunderstorm 25 %
Heavy Rain 6.5 %
Beijing ‘08To make probability of flash floods
start with the rain already on the ground...
Beijing ‘08 Look at the STEPS forecast...
Beijing ‘08 And any other good forecasts you can get ... this one’s from the Hong Kong “SWIRLS” system
Beijing ‘08 And do the stats on the ensemble to get the probability of hitting a threshold, given the obs rain..
..... Export the threat polygons to VIPS..
Beijing ‘08 Rainstorm Warning Products issued by Chinese forecasters using realtime FDP information
Beijing ‘08 Start with the TIFS interface…. single radar, single track-set TS Warning generation.....
Thunderstorm strike probability
Histogram of storm detections wrt forecast (normalizedspeed and direction). after Dance, Ebert, Scurrah
Mathematics
where (x, θ is a point in polar coordinates, t is forecast time, V is speed, σv is speed standard deviation, σ θ direction standard deviation. after Dance, Ebert, Scurrah
=
PDF that thunderstorm centre is over a point, based on Gaussian distribution in polar coordinates.
Strike probability field (with contours) for storm over 1 hour (black = 1, white = 0)
Beijing ‘08 Ensemble strike probability calculated in TIFS... Automated and Manual versions.....
..... Export the threat polygons to VIPS..
Beijing ‘08 But not before the expert forecaster adjusts the nowcast....
Beijing ‘08 During the adjustment ....
Beijing ‘08 After adjustment ....
Beijing ‘08 Thunderstorm and lightning threat products issued by Chinese forecasters using realtime FDP information