Centre for Atmospheric and Oceanic Sciences (CAOS)
Recent Submissions
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Predictability of tropical coupled ocean-atmosphere model and its dependence on initial conditions
El Niño and Southern Oscillation (ENSO) is the dominant interannual signal in the tropics. This aperiodic phenomenon arises out of strong interactions between the tropical ocean and the atmosphere. Investigations with ... -
Bay of Bengal freshwater in the tropical Indian Ocean
The annual total continental runoff into the Bay of Bengal (BoB) is more than half the runoff into the entire tropical Indian Ocean. The net freshwater (FW) content in the Bay of Bengal mixed layer increases from a minimum ... -
Andaman sea circulation in a high-resolution OGCM
The objective of this study is to understand the circulation of the Andaman Sea, which is unique by geography and oceanography, using a high-resolution Ocean General Circulation Model (ROMS) in tandem with altimeter and ... -
Investigation on the linkage between mystery of excess atmospheric absorption and state of mixing of aerosols
In order to understand the response of the Earth–atmosphere system to anthropogenic aerosol forcing, it’s essential to know the relative impact of the various aerosol species on the radiation budget. Most of the models ... -
Spatio-temporal characteristics of precipitating clouds and rainfall over the Western Ghats of India
One of the heaviest rainfall receiving regions during the Indian summer monsoon season is anchored around the orographic barriers of the Western Ghats (WG) in peninsular India. The high rainfall is attributed to the forced ... -
The Seasonal ENSO Transition Mode of the Southern Hemisphere: Definition, Characteristics and Impact
Decadal climate variability (DCV) exerts a profound influence on the global climate system by shaping background oceanic and atmospheric conditions. It drives long-term changes in sea surface temperatures (SSTs), monsoon ... -
Role of buoyancy in driving upper ocean mixing across timescales
This thesis explores the response of the upper ocean to surface buoyancy fluxes on different timescales using theory, numerical simulations and observation-based datasets. First, we investigate the role of evaporation in ... -
An investigation of the sensitivity of climate feedbacks to the latitudinal distribution of radiative forcing using the radiative kernel approach
It is well known that climate sensitivity, defined as the global mean surface temperature change per unit radiative forcing, depends on the forcing agents (such as CO2, CH4, O3, aerosols, solar radiation, land cover change, ... -
Investigating controls on intraseasonal convection and the abrupt seasonal transition in the boundary layer during monsoons
As solar insolation increases in the northern hemisphere during boreal summer, it is accompanied by an abrupt change in the circulation associated with the monsoons as well as heightened intraseasonal convective activity ... -
Poleward propagating Tropical Intraseasonal Oscillations over the Indian Ocean
The mechanisms of poleward propagation of tropical intraseasonal oscillations (ISOs) are not well-understood. In this thesis, we investigate this issue for two such tropical ISOs over the Indian Ocean, namely, the Boreal ... -
Role of equatorial convection and moisture in the structure and propagation of Boreal Summer Intraseasonal Oscillations
Boreal Summer Intraseasonal Oscillation (BSISO) is the dominant mode of tropical variability during Boreal summers. BSISO is manifested by northward propagation of the Maximum Cloud Zone (MCZ) from the warm equatorial ... -
A model-based investigation of the long-term climate and carbon cycle consequences of fossil fuel emissions, land use changes and negative emissions
In this thesis, we investigate the effects of anthropogenic perturbations such as fossil fuel emissions, deforestation, afforestation and negative emissions on the long-term climate and carbon cycle using simulations from ... -
Revisiting the General Circulation of the Tropics
This thesis examines some aspects of the tropical general circulation. First, we consider the zonal momentum budget of the tropical upper troposphere. Our motivation is the zonal inhomogeneity of the Earth that presents ... -
Arabian Sea High Salinity Core in the Bay of Bengal
The Summer Monsoon Current (SMC) advects high salinity water from the Arabian Sea into the Bay of Bengal (BoB) during the summer monsoon. This high salinity water subducts and enters the BoB as a subsurface high salinity ... -
Extratropical Influence on the Sub-seasonal Rainfall Deficit in Indian Summer Monsoon
The variability of Indian monsoon on a range of timescales - seasonal to interannual to decadal - has been studied and characterised extensively over the past several decades. On the mechanistic front, the role ... -
Intense Rainfall Events over the West Coast of India
West coast of the Indian peninsula is one of the regions which receive very heavy rainfall during the summer monsoon season. Average June-September rainfall over the parts of coastal Karnataka, Konkan and Goa exceed 250 ... -
An Energetics Perspective for the Response of the Indian Summer Monsoon to Land Processes in a Coupled General Circulation Model
The Indian summer monsoon is a coupled land-ocean-atmosphere phenomenon that supplies about 80% of the annual rainfall that the region receives. The monsoon season typically begins on June 1 st with a steep rise in rainfall ... -
Impact of 3D distribution of Black Carbon aerosols in the atmosphere on aerosol radiative forcing over the Indian region
Black Carbon (BC) aerosols are produced by the incomplete combustion of carbonaceous materials. While they constitute an insignificant mass-fraction of the composite atmospheric aerosols, their measurement is essential in ... -
Tropical Teleconnections to the Indian Summer Monsoon in Observations and in a Coupled Model
An accurate seasonal prediction of Indian summer monsoon rainfall (ISMR) holds immense importance for the socio-economic well-being of South-Asian countries, as it directly impacts agricultural output and overall economies. ... -
A Tropical Survey of Mid-Tropospheric Cyclones, their Classification and Genesis over the Arabian Sea
Middle Tropospheric Cyclones (MTCs) are moist synoptic tropical systems with vorticity maxima in the middle troposphere and weak signature in the lower troposphere. We begin with a tropical survey of MTCs; in South Asia, ...
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