Carbon Monoxide Emissions from the Southern Ocean Estimated by Underway Measurements

Atmospheric carbon monoxide (CO) plays an important role in ozone-related chemistry in the troposphere, especially under low-NOx conditions like the open ocean. While the ocean has been known as a source of atmospheric CO, previous studies reveal large discrepancies among their source strength estimates. Thus, clarifying the contribution of the ocean to atmospheric CO budget is essential to understand atmospheric chemistry. During austral seasons of 2009 through 2012, we performed continuous shipboard measurement of atmospheric and dissolved CO in the Southern Ocean and along the trans-pacific passage from Incheon, Korea to Christchurch, New Zealand. Based on our observation, we will present source strength estimate of CO in the Southern Ocean. Furthermore, global ocean emission of CO will be optimized using inversion analysis of our measurements and the result of 3-D global chemical transport model.