150年来大气甲烷浓度的长期变化

ATMOSPHERE METHANE TRENDS OVER THE LAST 150 YEARS

摘要: 应用作者建立的全球二维大气化学模式,采用2种CH4排放源的长期增长方案,同时考虑了CH4排放源以及对OH自由基浓度有重要影响的CO和NOx排放源的长期变化,模拟了CH4和OH从1840～2020年的长期变化趋势。考虑了世界人口增长的排放源方案可以更好地模拟CH4的长期变化,模拟结果表明,工业革命前的大气CH4浓度和年排放总量分别为760×10-9(V/V)和280×109kg,1991年大气CH4的浓度和年排放总量分别为1611.9×10-9(V/V)和533.9×109kg,对流层OH自由基数浓度从1840年的7.17×105分子数/cm3下降到1991年的5.79×105分子数/cm3,降低了19%。工业革命以来大气CH4的增长一方面是由于CH4排放源的增长,另一方面是由于大气OH浓度的下降。

Abstract: With two long-term emission scenarios of CH4, long-term trends of CH4 are simulated by using a global two-dimensional chemistry model. The modeled CH4 concentrations have a good agreement with observation. The results show that the concentration and emissions of CH4 are 760×10-9V/V and 280×109 kg before industrial revolution, 1611.9×10-9V/V and 533.9×109 kg in 1991, Simulated number concentrations of OH radicals are 7.17×105/cm3 in 1840,5.79×105/cm3 in 1991, and will be 5.47×105/cm3 in 2020. The increase trend of atmospheric CH4 is caused by the increase of emission of CH4 and decrease of OH radicals.