Ecology of Chaetognaths in the Indian EEZ

This thesis entitled ecology of chaetognaths in the indian EEZ.The present study, in general, deals with the distribution pattern of mesozooplankton biomass and abundance with special reference to the detailed ecology of the important carnivorous planktonic group, the chaetognath, in the two major ocean basins of the Indian EEZ, the Arabian Sea (AS) and the Bay of Bengal (BoB). Prior to the International Indian Ocean expedition (IIOE, 1960 – 1965), cmprehensive studies on chaetognath in the Indian waters were very limited and was confined mostly to some coastal and oceanic regions. The study revealed a profound influence of different physical process on the abundance of chaetognath community. The significant influence exerted by different physico-chemical factors on the vertical distribution of chaetognath species was also evident. Prior to this study, only very little information was available on the ecology and distribution pattern chaetognaths in both the Arabian sea and the Bay of Bengal in relation to various mesoscale processes and physicochemical .variables. This study, emphasizing the short term and long term influences of different meso-scale and basin scale physical events on the ecology of this important plankton group provides the baseline data for extensive ecological research on any major mesozooplankton group in this tropical low latitude region.

Tropical Mesoscale Convective Systems and Associated Energetics : Observational and Modeling Studies

The main purpose of the thesis is to improve the state of knowledge and understanding of the physical structure of the TMCS and its short range prediction. The present study principally addresses the fine structure, dynamics and microphysics of severe convective storms.The structure and dynamics of the Tropical cloud clusters over Indian region is not well understood. The observational cases discussed in the thesis are limited to the temperature and humidity observations. We propose a mesoscale observational network along with all the available Doppler radars and other conventional and non—conventional observations. Simultaneous observations with DWR, VHF and UHF radars of the same cloud system will provide new insight into the dynamics and microphysics of the clouds. More cases have to be studied in detail to obtain climatology of the storm type passing over tropical Indian region. These observational data sets provide wide variety of information to be assimilated to the mesoscale data assimilation system and can be used to force CSRM.The gravity wave generation and stratosphere troposphere exchange (STE) processes associated with convection gained a great deal of attention to modem science and meteorologist. Round the clock observations using VHF and UHF radars along with supplementary data sets like DWR, satellite, GPS/Radiosondes, meteorological rockets and aircrafl observations is needed to explore the role of convection and associated energetics in detail.