Evidence of seasonal enhancement of CO in the upper troposphere over India

Abstract

The vertical profiles of carbon monoxide (CO) mixing ratios retrieved from the Earth Observing System (EOS), Microwave Limb Sounder (MLS) onboard the Aura satellite for the period 2005-2009 and the EOS Tropospheric Emission Spectrometer (TES) onboard Aura for the period 2006-2007 were used to examine the evolution of pollutant CO in the upper troposphere (UT) over India. The Model for OZone And Related chemical Tracers version 2 (MOZART-2) was used to examine the seasonal transport of CO in the UT. The satellite observations revealed vertical transport of CO (80-90 ppb) from the surface to the UT during the summer monsoon season. The regular feature of enhancement of CO in the UT over India is presented. The results obtained by the MOZART-2 simulations (for the years 2000-2005) agree with the observations and indicate transport of boundary layer CO to the tropopause during the monsoon season. The observed enhanced CO mixing ratios in the UT are explained by processes involving monsoon convection.