Soil and vegetation canopy temperature gradients: Implications for SMOS

We present the diurnal variation of vertical temperature gradients measured in a maize canopy over the course of a growing season in the context of the SMOS mission. For the 6 AM and 6 PM overpass times, gradients were actually smallest in magnitude at 6 PM. The mean, standard deviation, and extreme values of the temperature differences between the top of the canopy and the soil surface and between the soil surface and a depth of 4.5 cm at SMOS overpass times are reported.