Abstract
This study examines the role of Asian monsoons on transport and spatial variability of atmospheric CO2 over the Indian subcontinent, using transport modeling tools and available surface observations from two atmospheric CO2 monitoring sites Sinhagad (SNG) and Cape Rama (CRI) in the western part of peninsular India. The regional source contributions to these sites arise fromthe horizontal flowin conduitswithin the planetary boundary layer. Greater CO2 variability, greater than 15 ppm, is observed during winter, while it is reduced nearly by half during summer. The SNG air sampling site is more susceptible to narrowregional terrestrial fluxes transported fromthe Indo-Gangetic Plains in January, and to wider upwind marine source regions from the Arabian Sea in July. The Western Ghats mountains appear to play a role in the seasonal variability at SNG by trapping polluted air masses associated withweak monsoonalwinds. A Lagrangian back-trajectory analysis further suggests that the horizontal extent of regional sensitivity increases from north to south over the Indian subcontinent in January (Boreal winter). (C) 2014 Elsevier B.V. All rights reserved.