Global land surface phenology - Start of senescence

The satellite- derived phenology is computed on the long-term average of 10-day MODIS NDVI data produced by BOKU University starting from MOD13A2 and MYD13A2 V006 16-DAY Global data at 1 km resolution. Phenology was extracted using the SPIRITS software applied to the historical average of the smoothed NDVI over the period 2003-2016. For each pixel, start of senescence is retrieved, occuring at the time at which NDVI drops below 75% of the descending amplitude of the seasonal profile.