The tenth IMSC, Beijing, China, 2007 - International Meetings on ...

separately (SOI) and it is concluded that they are highly correlated in the period range 2-2.5
years to 4-6 years and 5.5-6.0 years respectively. It has also been observed that the climatic
anomalies such as drought in India and El-Nino off the coast of Peru are linked with the
Southern Oscillation (Walker circulation)
Kew Words: Monsoon rainfall, Southern Oscillation Index, El-Nino, Climatic fluctuations
Parallel Sessions:Forecast
Verification of Climate Predictions
Speaker: Albert R. Boehm
Albert R. Boehm
retired
albertboehm@juno.com
WEATHER VERIFICATION: Verification of climate predictions is based on the
considerable methodology that has been developed to verify weather forecasts. Thus, first the
methodology for weather forecasts is reviewed.
PURPOSE: Forecasts are verified for two purposes (1) Diagnostic verification- to give
forecasters feedback to improve their forecasts by removing bias, etc. (2) Quantify utility to
build user edibility (the probability a user thinks that they are correct)
TYPES OF FORECASTS
QUANTITATIVE: a specific value from a continuous variable e.g. 50deg. C
PROBABILITY FORECAST: a forecast plus the uncertainty that it will occur expressed as a
probability.
A probability forecast can be used to optimize utilty of a forecast by minimizing expected loss
or allowing for an alternate action: e.g. go on picnic but take an umbrella.
CATEGORY FORECASTS: a well defined event e.g.rain or no rain or a temperature below
freezing.
RANKED CATEGORIES results from a continuous variable divided into categories by a set of
thresholds e.g. temperature 0>