An estimate of the interhemispheric transfer of carbon monoxide from tropical general circulation data

Mean meridional wind data at the equator and carbon monoxide concentration data are used to estimate a mean annual flux of carbon monoxide into the Southern Hemisphere of 5 ×10⁶ g sec^–1. Transfer to the stratosphere is found to be very small and not significant in the global CO cycle. Essentially all of the CO observed in the Southern Hemisphere may originate in the Northern Hemisphere. With similar loss rates in both hemispheres the total production in the Northern Hemisphere is estimated to be about 580 million tons per year which compares with about 330 million tons produced from anthropogenic sources. Mean CO residence times are estimated as 0.8 yr and 0.6 yr in the Southern and Northern Hemispheres respectively. It is suggested that more concentration measurements of CO (and other trace substances) be made in the equatorial plane, particularly in the upper troposphere in the Indian monsoon period. The general approach can be applied to other substances once concentration data are available in extenso.