where Po = POD; Pn = PNE; B = BIAS.
The first two range between 0 and 1 and represent
respectively the probability that an occurred event
(wetness) and an occurred non-event (dryness) were
correctly simulated, while the BIAS shows the tendency of the model to under or over-estimate the
simulated phenomenon; if the BIAS is greater than 1 it
means that the simulated events are more than the
real ones.