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.
- In-situ observations for EFAS are collected, quality checked, and interpolated by the CEMS-Meteorological Data Collection Centre. The quality checks are presented in, the interpolation algorithm is Spheremap. PAPER BY VERA
The meteorological variables are upsampled from their native resolution to 0.05 degrees resolution using bilinear interpolation: the interpolation algorithm is implemented in the open-source pre-processor pyg2p. It is here noted that nearest neighbor interpolation was used for 0.1 degrees GloFAS set up (v3 and preceding versions).
2-metre temperature, 2-metre dew temperature, 10-metre U wind component, 10-metre V wind component, surface solar radiation downwards, surface thermal radiation are used to compute reference values of evapotranspiration according to the Penmann-Monteith equation, which is implemented in the open source pre-processor LISVAP .
LISFLOOD OS then takes as input total precipitation, 2-metre temperature, and reference evapotranspiration. Similarly to all the previous GloFAS versions, the computations for GloFAS v4 are completed with daily time steps for all the hydrological processes, and sub-daily (4 hours) time steps for the river routing. All the output variables are available with daily time steps.