Scatterplots of predictions and observations - Scatterplots

depict the extent of bias and error in the ensemble of hourly

prediction-observation pairs. Bias is indicated by the systematic

positioning of data points above or below the perfect correlation

line. The dispersion of points is a measure of the error in the

simulation. The scatterplot also reveals outlier predictionobservation

pairs.

Quantile-quantile plots - Quantile-quantile plots compare the

frequency distributions of rank-ordered observed and rank-ordered

predicted concentrations. The observed and predicted concentrations

are sorted from highest to lowest then plotted on an x-y

plot. This graphically depicts any model bias over the frequency

distribution.

"Paired" predictions of daily maxima - In attainment

demonstrations, particular interest is focused on daily maximum

ozone concentrations. One test that may provide insight into model

performance is to consider model predictions occurring within

±1 hour of the observed daily maxima at each monitoring site in the

nine grid squares surrounding and including the monitor. The

"prediction," for purposes of this pairing, would be the one that

agrees most closely with the observed daily maximum for each site.

This method may be useful for sparse meteorological and air quality

networks, because it recognizes that both the inputs and air

quality observations have some attendant uncertainty. Resulting

comparisons can be superimposed on a map depicting emissions and

monitors to help assess model performance.

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castellano: DISPER CUSTIC DESCAR RADIA italiano:

castellano: DIS CUS DES RAD english: DIS CUS DES RAD

português: DIS CUS DES RAD italiano: DIS CUS DES RAD