Gross primary production (GPP) changes of natural vegetation in the Comunidad Valenciana

This work analyzes the vegetation changes in the Comunidad Valenciana observed during the period 2001-2018, using the daily GPP (Gross Primary Production) time series at 1-km spatial resolution derived from Earth observation-based (EO) data. The GPP time series have been obtained from EO-based data (e.g., MODIS/ Terra-Aqua and SEVIRI/MSG) and meteorological (e.g., precipitation and temperature) data using the light use efficiency model proposed by Monteith. The carbon fluxes detection has been performed by means of a multi -resolution analysis (MRA) based on the wavelet transform (WT). This analysis allows to decomposing the signal into different temporal resolution components. The interanual trend determines the vegetation change, positive (greening) or negative (browning) of vegetation photosynthetic activity over long-term scales. The negative long-term changes observed in natural vegetation reveal the presence of areas characterized by high degradated conditions. This is the case of Natural Pack of 'Serra d' Espada' in Castellon province, which is also controlled by a local ecosystem conservation program. To identify more precisely these areas, the areas affected by abrupt changes (associated to forest fires) in which vegetation has not been yet recovered have been removed. In this case, the results show a good agreement with the official burnt areas from the local government.