CENTRE FOR ATMOSPHERIC & OCEANIC SCIENCES
Indian Institute of Science
Bangalore, INDIA

 

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SCIENTIFIC ACHIEVEMENTS

 

For the first time, the observed northward propagating intraseasonal oscillations of the monsoon cloud band with 30-50 day time scale was simulated by a zonally symmetric general circulation model and a physical mechanism for the basic oscillation was provided (J. Atmos. Sci., 1984)

A physical mechanism for the observed north-northwest movement of the Monsoon Depressions provided (Nature, 1987) 

First quantitative estimates of the predictability of the tropical coupled ocean-atmosphere system made (J.Climate, 1991). 

A set of intraseasonal unstable modes due to coupled moist processes have been discovered in the tropical coupled ocean atmosphere system and linked to a periodicity of the coupled system (Geophys. Res. Lett., 1991; Proc. Indi. Acad. Sci. (EPS), 1993). 

The physical mechanism behind the "Spring predictability barrier" in the coupled ocean atmosphere system has been identified. This has laid the foundation for developing initialization scheme for coupled forecasts (Mon. Wea. Rev., 1997). 

An improved linear model for simulating both the annual cycle and interannual variability of surface wind in the tropics has been developed (Q. J. Roy. Met. Soc., 1996)

A quasi-biennial oscillation (QBO) of the tropical atmosphere that can be sustained purely due to internal dynamics has been discovered based on a series of multiyear integrations with a GCM (J. Climate, 1998). 

A physical mechanism for the internal QBO of the tropical atmosphere has been proposed (Pramana, 1997). 

Physical mechanism through which El Nino and Southern Oscillation (ENSO) influence Indian summer monsoon rainfall is elucidated based on analysis of 15 year observations and a 15 year GCM simulations  (Ind. J. Mar. Sci., 1998). 

A new broad scale index for the Indian summer monsoon has been proposed based on precipitation and a corresponding circulation index has been discovered which relates strongly with the proposed Indian monsoon precipitation (Q. J. Roy. Met. Soc., 1999). 

Analyses of daily surface winds for ten years reveal the seminal role played by the intraseasonal oscillations in modulating both synoptic and interannual variability of the Indian summer monsoon (Proc. Ind. Aca. Sci., 1998). 

A new mode of variability discovered in the Indian ocean ( Nature, 1999).