CEMS-Flood meteorological forcing are derived from observations or from NWPs: the list and usage of data sources is provided by CEMS-Flood meterological forcing and land surface data - Copernicus Emergency Management Service - CEMS - ECMWF Confluence Wiki.
This page briefly explains the pre-processing of the observations or NWPs to prepare the gridded dataset required as input to the hydrological model LISFLOOD OS. Specifically, the required inputs are total precipitation, 2-metre temperature, and reference evapotranspiration.
- Observations for EFAS are collected, quality checked, and interpolated by the CEMS-Meteorological Data Collection Centre (more details in this page). The interpolation algorithm is Spheremap: more details can be found in Thiemig et al. 2022.
NWPs are upsampled from their native resolution to the desired resolution of EFAS and GloFAS using the interpolation algorithms implemented in the open-source pre-processor pyg2p. Nearest neighbor interpolation was used up to EFAS v4 and GloFAS v3 (5km European and 0.1 degrees global set-ups, respectively). Bilinear interpolation is used for EFAS v5 and GloFAS v4 (1 arcmin European and 0.05 degrees global set-ups, respectively).
Reference values of evapotranspiration are computed using either observations or NWPs and following the Penmann-Monteith method, which is implemented in the open source pre-processor LISVAP.