Rain intensity#
Weather radars provide snapshots of the precipitation field. From these snapshots, a short-term forecast is generated.
Short-term forecast (Nowcasting)#
Radar Nowcasting is based on the estimation of the precipitation displacement field from observations. Using cross-correlation techniques, the displacement between precipitation observations at different scales is estimated to obtain a multivector displacement field representing the precipitation displacement. This field is then used to advect (project into the future) the latest observations to obtain a precipitation forecast for the next few hours.
The quality of the short-term forecasts decays over time, but the rapid updating of the information allows a new forecast to be obtained each time new data becomes available.
The Nowcasting algorithm applied in the platform has been developed by the Centre de Recerca Aplicada en Hidrometeorologia (CRAHI) of the Universitat Politècnica de Catalunya (UPC). Find below the references:
Berenguer, M., C. Corral, R. Sánchez-Diezma and D. Sempere-Torres, 2005: Hydrological validation of a radar-based nowcasting technique. Journal of Hydrometeorology, 6, 532-549.
Berenguer, M., G. G. S. Pegram, and D. Sempere-Torres, 2011: SBMcast – An ensemble nowcasting technique to assess the uncertainty in rainfall forecasts by Lagrangian extrapolation. Journal of Hydrology, 404, 226-240.
Useful links#
SMC Radar - Rainfall intensity#
From the instantaneous images of the radar network of the Servei Meteorològic de Catalunya (SMC), the technique of Nowcasting is applied to generate a precipitation forecast for the next hours.
The frequency of the SMC radar-based rainfall intensity product is 6 minutes.
Units are mm / 6 minutes.
Temporal resolution#
The last 6 hours of observed data and 2 hours of forecasted data are available, with a time step of 6 minutes.
Update frequency#
Data is updated in real time. A new forecast is run each time a new radar image is acquired, approximately every 6 minutes.
Data sources#
The SMC radar network is used.
AEMET Radar - Rainfall intensity#
From the instantaneous images of the radar network of the Agencia Estatal de Meteorología (AEMET), a Nowcasting technique is applied to generate a precipitation forecast for the next hours.
The frequency of the AEMET radar-based rainfall intensity product is 10 minutes.
Units are mm / 10 minutes.
Temporal resolution#
The last 6 hours of observed data and 2 hours of forecasted data are available, with a time step of 10 minutes.
Update frequency#
Data is updated in real time. A new forecast is run each time a new radar image is acquired, approximately every 10 minutes.
Data sources#
The AEMET radar network is used.
Met Éireann Radar - Rainfall intensity#
From the instantaneous images of the radar network of Met Éireann, a Nowcasting technique is applied to generate a precipitation forecast for the next hours.
The frequency of the Met Éireann radar-based rainfall intensity product is 5 minutes.
Units are mm / 5 minutes.
Temporal resolution#
The last 6 hours of observed data and 2 hours of forecasted data are available, with a time step of 5 minutes.
Update frequency#
Data is updated in real time. A new forecast is run each time a new radar image is acquired, approximately every 5 minutes.
Data sources#
The Met Éireann radar network is used.