Two contrasting summer monsoon seasons in the recent past decade: An observational study

India experienced two extreme summer monsoons, 2007 (active monsoon) and 2009 (weak in the recent past decade. The characteristic features of these contrasting Indian monsoons have been presented. country received 11.8% excess 17.1% deficit rainfall during monsoon seasons, respectively. These large deviations encourage us to study influence meteorological factors on activity. distributions over India, latent heat flux, wind, Vertically Integrated Moisture Transport (VIMT), Divergence (VIMD) values layer 1000–300 hPa for domain, 0°–40°N, 40°–120°E seasons are evaluated. In active monsoon, (i) predominant low level southwesterly flow Arabian sea deflection winds Bay Bengal, strengthening tropical easterly jet stream, wide area extent easterlies upper troposphere, maximum strength troposphere (150 hPa) is observed around 10°–15°N 70°–75°E; (ii) position subtropical ridge more northward, i.e., 32°N; (iii) a moisture transport from Southern Hemisphere, Sea Bengal mainland, westward/northward coverage larger quantum flux seen; (iv) number mesoscale systems. reverse true weak monsoon. Positive (neutral) Ocean Dipole (IOD) La-Nina (El-Nino) conditions lead (poor) (2009) year.