抄録
Severe floods in Pakistan brought many casualties and economic losses in 2010. It is reported that global warming has potential to increase a risk of extreme climate event. Recently a new approach called Event Attribution was developed to quantify the contributions of global warming to specific climate events such as floods in Pakistan. In this approach, large ensemble simulations are generated by an atmospheric general circulation model (AGCM) both under realistic climatic conditions and ideal climatic conditions assuming global warming is not occurring. Those simulations indicated that a specific pressure pattern associated with a wave train from Russia, which is natural variability rather than global warming, enhanced rainfall in Indus River Basin in 2010. Taking advantage of the large ensemble, we investigated how the rainfall developed to the extreme heavy rainfall in 2010. Composite analysis showed that unusual moisture convergence from Arabian Sea due to the specific pressure pattern had played an important role to cause heavy rainfall in 2010.
