DESCRIPTION: PR-ASS-1
Instantaneous and accumulated precipitation at ground computed by a NWP model

Fields of precipitation rate and accumulated precipitation generated by NWP model to provide spatial-temporal continuity to the observed fields otherwise affected by temporal and spatial gaps due to insufficient and inhomogeneous satellite cover. The product will be provided at several forecast steps (typical: 3, 6, 12 and 24 h forecast).

  • Coverage: Mid of Development Phase: COSMO-ME [approx. 30-55°N lat., 5°W-35°E lon.] Domain; Last part of Development Phase: H-SAF area [25-75°N lat, 25°W-45°E long]
  • Cycle: Development Phase (Version-1): 12 h - Last part of Development Phase (Version-2): 6 h
  • Resolution: Grid mesh: 7 km
  • Accuracy: For 3-h forecast: precipitation rate 50 %, accumulated: 100 %.
  • Timeliness: At fixed times of the day, 4 h after nominal time of analysis (00, 12)and, in Version-2, 06, 18 UTC)
  • Dissemination: By dedicated lines to centres connected by GTS - By EUMETCast to most other users, especially scientific
  • Formats: Binary output (GRIB) in rotated regular lat-lon grid. - Also standard graphic format for quick-look

Short description of the basic principles for product generation

Assimilation - Synoptic and satellite data from geostationary and sun-synchronous satellites are collected over the NWP model integration domain. Through the assimilation process this information is blended in a statistically "optimal" way with the current model representation of the atmosphere, thus obtaining an analysed state which gives the best possible estimate of the current atmospheric state on the regular grid.

Forecast - The result of the assimilation process is not a deliverable per-sé, but is only used to initialise the NWP model which is the only source of precipitation rain rates and accumulations The product time T0 will be at the two main nominal forecast times (00, 12) (six hourly products will be available later on, at the last development stage). Precipitation forecast fields will be provided up to T0+ 24 h.

Models - A mesoscale non-hydrostatic model (COSMO-ME) with a resolution of 7 km and full physics parametrizations will be used (with 5 category prognostic water condensate).