Future change in Southern Hemisphere atmospheric blocking simulated using a 20-km-mesh AGCM
In the present-day climate, 20-km-mesh AGCM is in good agreement with the Japanese reanalysis (JRA25) in terms of the AU and AN blocking frequencies. The higher the horizontal resolution of the AGCM, the more accurate the simulated blocking frequency. 20-km-mesh AGCM can simulate the wintertime long-lived AU blocking well.
In the near future climate, no significant decreases in the frequencies of the AU and AN blockings are predicted during both summer and winter. In the future climate, a significant decrease in the AU blocking frequency is predicted during both summer and winter, whereas no significant decreases in the AN blocking frequency is predicted. The decrease in the AU blocking frequency during winter is more remarkable than that during summer. In the future winter, it is possible that long-lived (13>days) AU blocking will disappear altogether.