Initiation and Eastward-moving Processes of an Madden-Julian Oscillation Event Suggested from a Global High-resolution Simulations by NICAM

Abstract:

The 60-day long hindcasts were performed using a global cloud-system-resolving model, NICAM, to simulate two consecutive Madden-Julian Oscillation events observed during the CINDY2011/DYNAMO campaign periods. The horizontal grid spacings used were about 7 km and 14 km. Only a single hindcast was done on the 7-km mesh, but an ensemble hindcast composed of 6 members, which were initialized at different dates with one day intervals, were achieved on the 14-km mesh. Several sensitivity tests were performed on the 14-km mesh to examine influences from time evolution of Sea Surface Temperature (SST). The main conclusion from those sensitivity tests will be discussed. In addition, an interesting mistake in the 7-km simulation about the initiation process of the MJO event in November 2011 will be introduced as an example that suggests an initiation mechanism of the event.