Determining the effects of ENSO phenomena on Andean areas by applying radiometric indices on long time series

This paper presents the results obtained after applying different radiometric indices over sugarcane crops located in a Colombian Andean area, analyzing their possible correlation with ENSO phenomena. The study was performed over Landsat images acquired during a 28-year period. Given the change of sensor on-board Landsat satellites during the above mentioned period, preliminary radiometric transformations were applied to homogenize the data. Moreover, in order to reduce possible seasonal effects, only images acquired over the same period of the year were considered. Vegetation indices such as NDVI and PRI were applied, and the results were compared with the ONI index, allowing the identification of ENSO events, as well as the identification of patterns corresponding to damage caused by ENSO events. Detailed analysis over the decreased quality of vegetation, and therefore the soil, allowed us to confirm the validity of the proposed methodology.