Table 3: Root mean square errors (RMSE) of the frequency distributions of irradiance gradients of modelled data versus measurement in W/m². The new model is able to produce significantly smaller values of RMSE than the models of Aguiar and Skartveit for both locations, Lindenberg, 2005, and Carpentras, 2001.

ModelLindenbergCarpentras

Aguiar81318541
Skartveit47585112
New27873218