The north-west (NW) and central India summer rainfall is anti-correlated with east-equatorial Atlantic SST (EEASST). The negative EEASST anomaly weakens the inter-tropical convergence zone over Atlantic and west equatorial Africa which generates stationary wave meridionally with anomalous positive GPH over NW Europe. The anomalous positive GPH over NW Europe acts as center of action for the propagation of a Rossby wave train to NW India via Europe consisting of anomalous high over NW of India. This intensifies the Tibetan High westward which reinforces the outbreak of monsoon activity. Read more... (Yadav R.K., Climate Dynamics, Online, March 2016)

Isotopic analysis of rainfall at Port Blair, Andaman Island reveals that rain water isotopes undergo systematic depletions in response to the organized convection occurring over a large area and are modulated by the integrated effect of convective activities. Precipitation isotopes appear to be linked with the monsoon intraseasonal variability in addition to synoptic scale fluctuations. Very high depletion was observed in rain water isotopic values during the events of intense cyclonic activities in the Bay of Bengal. This anomaly is likely to leave its imprint in the isotopic composition of stalagtites/stalagmites growing in the coastal regions of Bay of Bengal, which may be used as a tool to study the past cyclonic activities when no instrumental data is available. Read more... (S. Chakraborty, N. Sinha, R. Chattopadhyay, S. Sengupta, P. M. Mohan & A. Datye, Scientific Reports, Jan 2016)

The study addresses the triggering mechanism for different flavours of El Nino in the recent decades. The results show that stronger boreal spring (Mar-May) through summer (June-September) westerly wind anomalies (WWA), with relatively stronger ocean pre-conditioning result in canonical El Nino, weaker ocean pre-conditioning and weaker WWA generate El Nino Modoki or central Pacific El Nino, stronger ocean preconditioning and weaker WWA lead to a basin wide warming pattern. The strength of the WWA is crucial in determining the strength of the ocean dynamic response and the thermocline displacements in the Pacific. The study has important implications for understanding the nature of El Nino in advance. Read more... (Jyoti J, Swapna P, Shamal M. and K. Ashok, Scientific Reports , Nov. 2015)