Variations of Indian summer monsoon rainfall induce the weakening of easterly jet stream in the warming environment?

An observational evidence of decrease in Indian summer monsoon rainfall in the recent three decades of global warming era

“…The moisture transport to the Indian mainland due to these southwesterlies dictates the rainfall activity over India. The moisture generated by the trade winds over the south Indian Ocean and the evaporative flux from the Arabian Sea have been brought by the strong cross equatorial low level jet stream towards India and its adjoining south Asia neighbors (Findlater, 1969;Naidu et al, 2011a). Joseph and Raman (1966) found that the low level jet stream exists over Peninsular India on a large number of days during July with a core speed of 40 to 60 knots near 1.5 km.…”

“…This decrease in summer monsoon rainfall is associated with a weakening of the southern oscillation and relaxation of the meridional temperature gradient over the Indian Ocean. Further, Naidu et al (2011a) reported that India experienced a weak summer monsoon epoch [1995][1996][1997][1998][1999][2000][2001][2002][2003][2004][2005] which is closely associated with weak tropical easterly jet stream and coincides with the warmest decade. The weakened tropical easterly jet stream is ultimately due to the reduced moisture advection as associated with weaker surface westerlies, and thus rainfall.…”

An observational evidence of climate change during global warming era

“…They attributed this decease to relaxation of SOI and north-south temperature gradient over Indian Ocean. Further, Naidu et al (2011) pointed that the variations in the summer monsoon rainfall induce the weakening of the tropical easterly jet stream in the warming environment i.e., global warming. The decrease of SM rainfall over India, the decrease in the frequency of cyclonic systems over the Bay of Bengal in monsoon season, the decrease of vertical shear in the zonal wind over the monsoon depression prone area, the negative values of SOI, the weakening of tropical easterly jet in the upper troposphere and weakening of westerly belt in the lower troposphere are observed in GW era.…”

Indian summer monsoon simulations with CFSv2: a microphysics perspective

“…8a-e; Table 3). Strength of TEJ is related with the monsoon activity over the Indian subcontinent (Naidu et al 2011;Chaudhari et al 2013). ZC90-simulated TEJ strength is 15.4 m/s which is underestimated as compared to observation (which has TEJ strength as 19.2 m/s).…”