The surface wetness energy balance (SWEB)
model was developed at Cornell University, USA
and is based on the ‘‘big leaf’’ concept (Magarey,
1999; Magarey et al., 2005). SWEB is a physical
model based on the energy balance. The model was
developed at the organ scale and it simulates the
surface wetness duration on a leaf. The agrometeorological
inputs of the model are air temperature (8C),
relative humidity (%), precipitation (mm), wind speed
(m s1) and net radiation above and below the canopy
(W m2); the output is the percentage of wet leaf
surface