1:45 PM - 3:15 PM
[AAS08-P07] Global scale large ensemble simulations using NICAM/NICOCO on Fugaku for week to seasonal predictions of high impact weather events
Keywords:Tropical cyclone, MJO, Air-sea coupling, Large ensemble, global cloud resolving model
Here we provide an overview of Theme 2 in the “Large Ensemble Atmospheric and Environmental Prediction for Disaster Prevention and Mitigation” program, which targeted extended-range (from over a week to several months) predictions of high-impact weather events, using the global cloud/cloud-system resolving model NICAM and its ocean-coupled version NICOCO. These targets require good model performance in producing not only the high-impact weather events themselves, but also largescale, longer-lived fluctuations of MJO/BSISO, ENSO, etc., by which the events are influenced.
Large ensemble member experiments (over 1000 members for 14 km mesh and 30-100 members for 3.5-7 km meshes, initial conditions provided from NEXRA and ALERA systems) were carried out for a typhoon landfall event (Faxai) and for MJOs. TC and MJO predictabilities of the model were investigated, and several key phenomena were identified that separate successful ensemble members from others. Meanwhile, there were progress in model development, especially in terms of cloud microphysics modification and coupling with ocean. Cloud properties and radiation balance were improved, and techniques to prevent model drift at seasonal time scales were installed. NICAM results were submitted to an intercomparison project for global storm resolving models (DYAMOND2) and is now being investigated by researchers over the world. The model was also run in an ideal aqua-planet mode to understand the climatological general circulation and its sensitivity to Earth orientation parameters. The obtained information and upgrades of the model are integrated to carry out upgraded seasonal Typhoon prediction attempts with NICOCO.
Acknowledgements: This work is part of “Program for Promoting Researches on the Supercomputer Fugaku” (JPMXP1020200305 by MEXT). (Project ID: hp200128/hp210166/hp220167). Tomoki Miyakawa is supported by JSPS KAKENHI Grant Number JP19H05703, 22H01297, and 19K03966.
Large ensemble member experiments (over 1000 members for 14 km mesh and 30-100 members for 3.5-7 km meshes, initial conditions provided from NEXRA and ALERA systems) were carried out for a typhoon landfall event (Faxai) and for MJOs. TC and MJO predictabilities of the model were investigated, and several key phenomena were identified that separate successful ensemble members from others. Meanwhile, there were progress in model development, especially in terms of cloud microphysics modification and coupling with ocean. Cloud properties and radiation balance were improved, and techniques to prevent model drift at seasonal time scales were installed. NICAM results were submitted to an intercomparison project for global storm resolving models (DYAMOND2) and is now being investigated by researchers over the world. The model was also run in an ideal aqua-planet mode to understand the climatological general circulation and its sensitivity to Earth orientation parameters. The obtained information and upgrades of the model are integrated to carry out upgraded seasonal Typhoon prediction attempts with NICOCO.
Acknowledgements: This work is part of “Program for Promoting Researches on the Supercomputer Fugaku” (JPMXP1020200305 by MEXT). (Project ID: hp200128/hp210166/hp220167). Tomoki Miyakawa is supported by JSPS KAKENHI Grant Number JP19H05703, 22H01297, and 19K03966.