The South-Flood North-Drought Pattern Over Eastern China and the Drying of the Gangetic Plain


Sumant Nigam

14:50:00 - 15:40:00

101 , Mathematics Research Center Building (ori. New Math. Bldg.)

The Indo-Gangetic Plain and the lowlands/plains eastward of the Tibetan Plateau exhibit substantial – at times, precarious – trends in summer precipitation since the mid-twentieth century. These include declining rainfall over the northern Gangetic Plain, and a meridional dipole over eastern China that is commonly referred as the South-Flood North-Drought (SFND) pattern in the region. The trends have been attributed to increased aerosol/dust loadings, significant land-use land-cover change, and increased greenhouse gas emissions, among others. Interestingly, multidecadal natural variability is not a commonly cited cause. The presence of oppositely-signed (i.e., increasing) rainfall trends in the first-half of the 20th century in some of the same regions prompted this reassessment of the role of multidecadal SST variability in generating summer rainfall trends over large parts of monsoon Asia.