[AAS01-08] 100-member ensemble forecast by NICAM to examine forecast bust case Typhoon Krosa (2019)
Keywords:ensemble forecast, NICAM, NEXRA, typhoon
To examine why such diversity in predicted tracks occurred, 100-member ensemble forecast experiments were performed using 28-km mesh nonhydrostatic icosahedral atmospheric model (NICAM). The model was initialized with NICAM-LETKF JAXA Research Analysis (NEXRA).
In the experiments initialized at 1200 UTC on 6 August showed large uncertainty of Krosa’s track as predicted in multicenter operational models and the west most simulated tracks captured Krosa’s analyzed track by RSMC Tokyo. An ensemble-based sensitivity analysis revealed that westward extension of subtropical Pacific high led to northwest/north-northwest trajectory. Dependency of initial data and mechanism which caused westward extension of the subtropical high will be discussed at the presentation.