Analysis On The Spatio-temporal Gradients Of Carbon Monoxide In China Using Remotely Sensed Data During 2003-2005

Carbon monoxide (CO) is the third most abundant carbon-containing component after CO2 and CH4 in atmosphere. CO is toxic to human health and plays a key role in determining the oxidizing capacity of atmosphere. It is the primary determinant of tropospheric hydroxyl radical (OH) concentration, therefore indirectly affects the atmospheric resident times of greenhouse gases such as methane and halocarbons, which are predominately removed by OH initiated oxidation. CO influences the atmospheric chemistry as well as climate. The atmospheric lifetime of CO is relatively long (3 months on average) and it can be transported at intercontinental scale. It has become an important environmental problem from fossil combustion, especially the regions with an increasing economic demand. Therefore, CO is an important atmospheric pollutant whose emissions and atmospheric concentrations need to be monitored.Consequently, Trace gases and aerosol emissions from China have been of particular concern, because of the country's fast economic growth in the last two decades. Therefore, it is urgent to better understand of the emissions and distributions of atmospheric CO. This study aims to understand the spatio-temporal gradients of CO in China and assess the influence of biomass burning and regional pollution on CO levels in China by using a consistent CO column dataset retrieved from SCIAMACHY/ENVISAT during 2003 to 2005. And then, the impact factors of carbon monoxide are analyzed using the satellite observations together with statistic dataset, population density, anthropogenic CO emissions and biomass burning emissions inventory, AASTR hotspots, ecoregions and soil layers.The yearly averaged CO has significant spatial variability. The high concentrations of CO are distributed on the Yangtze Delta, the Pearl Delta, Sichuan Basin, Beijing and its surrounding areas. The western China regions with lower CO vertical columns concentrations are in Qinghai-Tibetan Plateau. The list of annual average concentration of CO columns is as follows:the Bohai Rim region>the Yangtze Delta> the Pearl Delta, Their CO values are higher than that at the background concentration of WLG. The seasonal variation of CO vertical columns is obvious. The peak centers of monthly averaged carbon monoxide occurred in winter and spring, whereas the troughs in summer. Differences for the annual averaged CO over different soil and ecoregion layers are significant. The correlation between monthly carbon monoxide concentration with temperature over each ecoregion is different. The ecoregions with positive correlation coefficient are listed below:Southeast Tibet shrublands and meadows, Hengduan Mountains subalpine conifer forests, Yarlung Tsangpo arid steppe, Eastern Gobi desert steppe and Mongolian-Manchurian grassland. The negative correlation coefficient between CO and temperature existed in Jian Nan subtropical evergreen forests, Changjiang Plain evergreen forests, Huang He Plain mixed forests. Tarim Basin deciduous forests and steppe, South China-Vietnam subtropical evergreen forests and Taklimakan desert ecoregions.The CO concentration has a strong correlation with anthropogenic CO emissions inventory and statistical data on energy. Seasonal variations of CO in northeast and southern China have high correlations with burn areas. The regional pollution as well as biomass burning plays an important role for carbon monoxide levels over China and that SCIAMACHY is a promising tool for comprehensive understanding of carbon monoxide gradients and emissions.