Last updated: March 2018
COSMO-LEPS is the Limited Area Ensemble Prediciton System developed within COSMO consortium in order to improve the short-to-medium range forecast of extreme and localised weather events. It is made up of 20 integrations of COSMO model, which is nested on selected members of ECMWF ENS.
COSMO-LEPS started to run on an experimental-operatonal basis on November 2002 and, in November 2005, it became an ECMWF member-state time-critical application, managed remotely by Arpae-SIMC.
COSMO-LEPS runs twice a day, starting at 00 and 12UTC, using a 7 km grid spacing and 40 vertical layers, with a forecast range of 132 hours. The computer time to run the system at ECMWF is provided by a joint account, with the contributions of the COSMO countries which are also ECMWF member state (namely, Greece, Germany, Italy and Switzerland).
The rotated lat-lon coordinates of the lower left and upper right corner of the integration domain are lon=-15.75, lat=-16.125 and lon=16.125, lat=9.75, respectively. The coordinates of the Southern pole of rotation are: latitude=-40N, longitude=10E.
The orography (height in m) of the COSMO-LEPS integration domain.
COSMO-LEPS increases the ensemble size from 16 to 20 members run in Single Precision; no SPPT by now for stability problems.
COSMO-EU fields are no more used: ICON-EU data are used instead.
No more use of IFS-Bechtold convection scheme; all members use Tiedtke scheme.
No more use of Kain-Fritsch scheme (which is no more maintained); members 1-8 use Tiedtke convection scheme, members 9-16 use IFS-Bechtold convection scheme.
COSMO-LEPS doubles; it is run at both 00 and 12UTC.
introduction of (randomly chosen) perturbed parameters in COSMO-LEPS runs
COSMO-LEPS products are archived every 3 hours
the LM-det run is also produced; it is a further run of COSMO nested on the high-resolution deterministic forecast of ECMWF in the same configuration as COSMO-LEPS integrations (10 km, 32 ml, 120h range).
As for the 00UTC (12UTC) run, COSMO-LEPS application starts at about 07.30UTC (19.30UTC), once the ECMWF ENS has passed fc+144h forecast range. Products are disseminated to Met Ops rooms of COSMO weather offices starting from about 08.30UTC (20.30UTC).