Impact of equatorial and continental airflow on primary greenhouse gases in the northern South China Sea

摘要: Four-year ground-level measurements of the two primary greenhouse gases (carbon dioxide (CO2) and methane (CH4)) were conducted at Dongsha Island (DSI), situated in northern South China Sea (SCS), from March 2010 to February 2014. Their mean mixing ratios are calculated be 396.3 ± 5.4 ppm 1863.6 50.5 ppb, with an annual growth rate +2.19 0.5 yr–1 +4.70 4.4 ppb for CO2 CH4, respectively, over study period. Our results suggest that Asian continental outflow driven by winter northeast monsoon could have brought air pollutants into SCS, as denoted significantly elevated levels 6.5 59.6 which greater than marine boundary layer references Cape Kumukahi (KUM) tropical Pacific January. By contrast, summertime CH4 DSI is shown lower KUM 19.7 whereas no differences (<0.42 July) during same Positive biases Greenhouse Gases Observing Satellite (GOSAT) L4B data against surface estimated 2.4 3.4 43.2 36.8 CH4. The satellite products retrieved GOSAT showed effects anthropogenic emissions vegetative sinks on land a vertical profiling basis. prevailing southeasterly winds originating far south equator or Southern Hemisphere pass through troposphere forming tunnel relatively clean masses indicated low observed summer.