Soil water content is directly connected with soil evaporation and plant transpiration processes; in particular, soil water
content within the root zone, is readily available to evapotranspiration. Thus, in agricultural sciences, the assessment of
the spatial distribution of soil water content could be of utmost importance in evaluating crop water requirement.
In spite of limitations to applicability due to contingent cloud cover, water content of the upper part of the soil can be
determined by applying the thermal inertia approach by coupling optical and thermal infrared images. The thermal
inertia formulation, rigorously retrieved on bare soil, has been also verified on soils partially covered by vegetation. In
each case, one of the crucial steps is the assessment of the phase difference between surface temperature and solar
irradiation. Different approaches allow determining this latter parameter.
To this aim, three formulations to retrieve the phase difference were tested: i) the first, assuming a spatially constant
value based on the knowledge of the time when maximum surface temperature occurs; ii) other two methods, allowing
determining its spatial distribution through three or four thermographies.
In this framework, this research is focused to establish the simplest operational approach providing reliable results over
time using low-resolution MODIS images collected over an agricultural area of South Italy (Campania). Temporal
evolution of the remote sensing estimates have been compared to data collected by the micro-meteorological station
installed in a vineyard within the area.