Implications of interpreting tropical dry forest succession after radiometric correction of Chris/ Proba images

In the present paper, we evaluate the effect of cast shadows in the classification of three successional stages of tropical forest in Mexico using hyperspectral and multiangular Chris/Proba images. A simple algorithm based on the cosine of the angle of solar incidence on the terrain is applied to correct the effect of topography on Chris/Proba´s reflectances. Previous to the correction of topographic effects, Chris/Proba images were atmospherically corrected in BEAM software. Vegetation maps of the study site were generated using non-parametric decision trees, defining four mam classes: late, intermediate and early stages of succession within a tropical dry forest, and riparian forests. By the comparison of resultant vegetation maps before and after the correction of topography in Chris/Proba´s spectral data, we found that late stage of succession and riparian forests are overestimated in non-corrected images while intermediate and early stages of succession are underestimated. Errors in classification are more important in extreme Chris/Proba´s angles of observation. Thus, the radiometric correction of topography is necessary for an accurate classification of succession in tropical dry forests.