Monitoring the latent and sensible heat fluxes in vineyard by applying the energy balance model METRIC

Abstract

The monitoring of the energy fluxes over vineyard applying the one source energy balance model METRIC (Allen et al., 2007b) are shown in this work. This model is considered operaive because it uses an internalized calibration method derived from the selection of two extreme pixels in the scene, from the minimum ET values such as the bare soil to a maximum that corresponds to full cover active vegetation. The model provides the maps of net radiation (Rn), soil heat flux (G), sensible heat (H), latent heat (LE), evapotranspiration (ET) and crop coefficient (Kc). The flux values have been validated with a flux tower installed in the plot, providing a RMSE for instantaneous fluxes of 43 W m², 33 W m², 55 W m² y 40 W m² on Rn, G, H and LE. In relative terms are 8%, 29%, 21% and 20% respectively. The RMSE at daily scale for the ET is 0.58 mm day^-1, with a value in the crop coefficient for the mid stage of 0.42±0.08. These results allow considering the model adequate for crop monitoring and irrigation purposes in vineyard. The values obtained have been compared to other studies over vineyard and with alternative energy balance models showing similar results.