MiKlip first phase: LACEPS

A Limited-Area Climate Ensemble Prediction System

To support politicians drawing decisions on national or regional level with respect to climatological issues the downscaling of global climate predictions to the regional scale is essential. This downscaling is important for forecasts on all time scales and, thus, also on the decadal time scale. The assessment of the reliability of the forecasts and the probability of the occurrence of the calculated future climatic states are further important issues for the decision makers.
The main goal of the project LACEPS (within Module C of the MiKlip programme) is the development of a limited-area ensemble prediction system for medium-range climate on the regional scale using the COSMO-CLM regional climate model. This ensemble prediction system aims to span the complete space of all potential climate states responding to the incomplete knowledge and uncertainties of the model’s input data and the model’s inherent uncertainties. From the resulting ensemble probability density functions for each climate variable may be derived. For an optimum use of computing resources the number of ensemble members needs to be reduced to a robust subset of those approximating the probability density function of all forecasts best.
For the diagnostics of the LACEPS forecast quality it is planned to envisage the air temperature in 2 m height above ground and the total precipitation at the surface. These parameters are selected because they both have a high impact on economy, agriculture, policy, and society as well as on the daily life of the citizens.

Goals

  • Development of an Climate Ensemble Prediction System (CEPS) for decadal forecasts on the regional scale employing the regional climate model COSMO-CLM
  • Reduction of CEPS to those members representing the probability density function of all potential climate states best
  • COSMO-CLM simulations on a European model domain with horizontal grid width of 0.22° (approx. 25 km; project phase DS1) and 0.11° (approx. 12 km; project phases DS2 and DS3)
  • Target variables: air temperature in 2 m above ground, surface precipitation, humidity related parameters in the atmosphere

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Contact

Deutscher Wetterdienst
Dr. Barbara Früh
Dr. Claus-Jürgen Lenz