Ensemble-Based Forecast Indices for Area Forecast Using the Mesoscale Ensemble Prediction System in JMA

Japan Meteorological Agency (JMA) has responsibility for the issuance of SIGMET for Fukuoka FIR and domestic area forecast for flight, which include turbulence, icing, and CB-cloud forecast. To support forecasters in preparing that information, indices of turbulence, icing, and CB-cloud amount and height are calculated based on the JMA's mesoscale model (MSM) output. Although those indices have high accuracy over that observed the indices formerly used in JMA, more improvements are necessary for safety flight.

 JMA has experimentally operated the mesoscale ensemble prediction system (MEPS) with 11 members and the same configurations as the MSM to support in preparing warnings and information for disaster prevention and to provide information for the next generation air traffic control system in Japan. To achieve the purpose, we developed ensemble-based forecast indices of turbulence, icing, and CB-cloud amount and height using the MEPS. Basically those indices are calculated simply from each ensemble member. The results of verification showed that the ensemble-based indices improve forecast accuracy significantly over that observed with the original indices based on the MSM. This presentation will include the outline of the ensemble-based indices, the results of verification, and some case studies.