Nov 24, 2011

Change in the precipitation intensity of the East Asian summer monsoon projected by CMIP3 models

Shoji Kusunoki, Osamu Arakawa
Climate Dynamics
  • Investigates future change in precipitation intensity of East Asian summer monsoon using the present-day climate simulations (1991–2000) and the future climate simulations (2091–2100, A1B emission scenario) by the Couple Model Intercomparison Project 3 (CMIP3) models
  • States the target period is the month from June to July which is the main part of the rainy season over Japan and Korea
  • Quantitatively evaluates (in the present-day climate simulations) model’s reproducibility of precipitation climatology and Simple Daily precipitation Intensity Index (SDII), using skill S
  • Finds that models with higher reproducibility of precipitation climatology tend to show higher reproducibility of precipitation intensity
  • Finds that in the future climate simulations, simple Multi-Model Ensemble (MME) average using all models show the increase of precipitation intensity over almost all regions of East Asia
  • Introduces S as weighting factor and finds this does not make a large difference in the geographical distribution of precipitation intensity change
  • Finds that in case of MME using five best models, the geographical pattern of precipitation intensity change is qualitatively similar to that using all models, but the local magnitude of changes are much affected by the best model
  • Calculates change in vertically integrated horizontal transport of moisture in order to interpret future change in precipitation climatology and SDII
  • States that changes in precipitation climatology and SDII can be interpreted as the moisture convergence change associated with change in horizontal transport of moisture
  • Finds that large moisture convergence was due to either intensification or weakening of subtropical high depending on models