Operational OpenRoad verification
Presented by Robert Coulson
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Operational OpenRoad verification
• Introduction
• Verification Methodology
• Temporal Verification
• Economic skill in forecasts
• Questions and Answers
© Crown copyright Met Office
Operational OpenRoad Verification
•
•
•
Site specific verification.
> 300 sites are verified.
Observations from roadside sensors are used as TRUTH
against
thebasis
forecasts
are verified.
Road travel
onwhich
a timely
is essential
for economies globally in the
• A large
modern
world.sample size of matching forecast/observation pairs are
collected over individual months and for the whole winter
Cold winter
climates
impact
safetyvalidation
with dangerous
travelling conditions
season
for each
site toonensure
is reliable
causing delays if not acted upon.
Therefore, the prediction and prevention of ice formation is imperative to
mitigate against these.
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Verification Methodology
• Categorical verification of road surface frosts
ss
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Communication to end users
2x2 table
Observed Frost
No Observed
Frost
No Forecast
Frost
Miss (c)
Correct Rejection
(d)
Forecast Frost
Hit (a)
False Alarm (b)
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Temporal Verification
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N by M contingency table
The road surface sensors enable the actual state of the road
surface to be deduced, and this enables a time-series profile
to be verified against the forecast road state.
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Economic skill values for forecasts
•Relative
economic
valueratio
Relative
value(V) ~ Cost-loss
Road Surface Temperature Oct-April 2011/12 (UK)
1
Value Added Forecast
0.8
Forecast
0.6
V
0.4
0.2
0
0.0
0.1
0.3
0.4
0.5
Cost-loss ratio
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0.6
0.8
0.9
Economic skill values for forecasts
Marginal Night analysis
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Questions and answers
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