Algorithm for the disaggregation of crop area statistics in the MARS crop yield forecasting system

This report describes the algorithm to disaggregate regional crop area statistics in Europe, at all NUTS and GAUL administrative levels and onto a regular grid of 25 km. This algorithm is necessary to aggregate crop indicators in the MARS Crop Yield Forecasting System (MCYFS) from the original resolution of the BioMA-WOFOST crop model resolution at EMU and 25 km grid cells to national and sub-national scale when using these indicators operationally for crop yield forecasting (e.g. MARS Bulletins). The algorithm uses as input crop area statistics from Eurostat and national statistical services delivered from the Member States, and land cover. Rules and operations are set to construct, combining the mentioned sources, the full hierarchical system of regional weights per crop and year, expressing the proportion of crop area in every single spatial unit (region or grid) of the total national crop area. These regional weights provide, when multiplied by the national figures, the distribution of crop areas over Europe at grid and at administrative levels. Moreover, it can be used in the spatial aggregation or disaggregation of any crop indicator based on crop area. The current disaggregation is available up to 2022 and is based on weights derived from subnational statistics available till 2020. The introduction (Section 1) describes the spatial framework and the main principles of indicators aggregation in use in the MCYFS. In Section 2, the processing steps of the aggregation are explained in depth. Section 3 reports the outputs of this algorithm that can be downloaded from the Agri4cast Resources Portal.