The effect of dew on L- Band emissions from a vegetation canopy

Abstract

The effect of dew in a vegetation canopy on the L-Band thermal emissions is studied. An approximate electromagnetic model for dew on a leaf is used in conjunction with a Radiative Transfer to compute the thermal emissions. The dew is modeled as a thin uniform layer covering the entire surface of the leaf. From this model, the scattering amplitudes and phase functions are computed. These are then used in both the τ-ω model and a first-order Radiative Transfer model to compute the emissivity from the vegetation canopy in the presence of various amounts of dew. The τ-ω model predicts a decrease in emissivity as the dew amount increases. However, the inclusion of first-order scattering predicts the opposite relationship, where an increase in dew results in an increase in emissivity.