Drought indicator time series for European NUTS regions based on remote sensing data (2000-2015)

Time series for three drought indicators based on remote sensing have been extracted for European NUTS regions (level 0, 1, 2 and 3). The Nomenclature of Territorial Units for Statistics, (NUTS, for the French Nomenclature des unités territoriales statistiques), developed by the European Union, is a geocode standard for referencing the administrative divisions of countries for statistical purposes. A land use mask was applied to extract the time series, to differentiate the contribution of crops, grass, forest and shrubs. There is also one time series for each NUTS region which includes all classes. The land cover product used to produce the mask was remote sensing MODIS product MCD12C1 (year 2012) which has a 0.05 degree resolution. The three drought indicators extracted are (i) the Vegetation Condition Index (VCI) based on satellite product NDVI (Normalised Difference Vegetation Index) (ii) the Temperature Condition Index based on remotely sensed LST (Land Surface Temperature) and (iii) the Vegetation Health Index (VHI) which is a combination of VCI and TCI. These indicators were first calculated as a gridded product for Europe with a 0.05 degree resolution and monthly time step (2000-2015), using MODIS product MOD13C2 for NDVI, and MODIS product MOD11C3 for LST, following methodology described by Kogan (1995; https://doi.org/10.1016/0273-1177(95)00079-T). The time series were then extracted applying the simplified land use classification mask (crops, forest, grass, shrubs) to each NUTS region, and an additional time series for all classes. For each time step, a value was produced only if at least 50% of the pixels within the non-masked area had valid values. NOTE: there are two types of "No Data" value. Value '--' means there were no pixels with valid values within the non-masked area. Value 'nan' means there were some pixels with valid values within the non-masked area, but these covered less than 50% of the area. These time steps were discarded as less than 50% was considered not representative enough of the whole area.