Indian Monsoon Paths and Blocking Effects on Pakistan Extreme Rainfall Events

Abstract

 Pakistan experienced an extreme rainfall event in July to August 2010. Two of the major contributing factors behind this extreme event were upper level stagnant blocking over western Russia and meandering pattern of Indian monsoon. In this study, monsoon patterns were identified. The kind of monsoon pattern that affected 2010 Pakistan flood consists of 64% of total flooding events in Pakistan. We focus on sea level pressure anomaly on 3 identified patterns of monsoon meandering. In 2010 Pakistan flooding case, the sea level pressure anomaly over the Middle East was lower, whereas, the anomaly over Northwestern Russia was higher. Moreover, 2010 Pakistan flooding case was affected by stagnant upper level (500hPa) blocking to descend cold air from Siberia to Pakistan. The number of monsoon meandering pattern which affects Pakistan flood tended to increase from June to August. On the other hand, the number of simultaneous occurrence of upper level blocking tended to decrease from June to August.