Correlazione tra la dimensione del footprint e le variabili esogene misurate da stazioni eddy covariance in Pianura Padana

This article aims to compare the footprint size, estimated by a hybrid model, with the main exogenous variables measured by eddy covariance station. The empirical equations that have been obtained in this article comes from the analysis of the data measured by Livraga (LO) station, and then validated using the data by Landriano (PV) station. The eddy stations are located in a maize field in Po Valley. Furthermore, we want to define some universal relations between the footprint size and these variables and, if necessary, to use the dimensionless variables. The hybrid model is based on a combination of Lagrangian stochastic models and dimensional analysis. The advantage that this study can bring is to have an estimation about the dimension of the representative area that affects the measure of detectors, starting with the knowledge of simple parameters that can be measured easily. The practical purpose is to give, during the time of the project, the correct position of the eddy covariance station in the field, without using expensive instrumentations such as sonic anemometer and gas analyzer. Although, the results of direct comparisons between the footprint and exogenous variables are not very satisfactory, while the comparison between exogenous variables and stability parameter of the atmosphere is particularly interesting. From this comparison we obtained some empirical relations that can be applied to different sites.