大气甲烷浓度的控制因子及对大气氧化剂的影响

项目名称： 大气甲烷浓度的控制因子及对大气氧化剂的影响

项目编号： No.41475112

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 张霖

作者单位： 北京大学

项目金额： 70万元

中文摘要： 大气甲烷对于气候变化和空气污染都有着重要的研究意义。它是仅次于二氧化碳的最主要的人为温室气体，同时也影响对流层的氧化剂气体，如OH自由基和臭氧，从而影响大气对污染的清除能力。我们对控制甲烷浓度的因子及它对大气氧化剂的影响尚未清楚。本项目将应用地面网络和多个卫星仪器的观测资料分析大气甲烷在1985-2012年间的年际变化。本项目将应用污染物历史排放清单和再分析气象场进行近30年的全球大气化学模拟，分析对流层OH浓度的年际变化及对甲烷浓度年际变化的影响。本项目将结合地面甲烷碳-13 (C-13) 同位素观测和卫星观测资料（SCIAMACHY和GOSAT），应用大气化学模型模拟甲烷C-13同位素，并应用伴随模式反演估计甲烷的排放源，从而分析不同种类源的全球分布、相对贡献和变化。本项目将进一步分析近30年来大气甲烷浓度的年际变化引起的对流层OH和臭氧的变化，认识甲烷对气候变化和大气污染的影响程度。

中文关键词： 大气污染；气候变化；甲烷；伴随模式；碳同位素

英文摘要： Atmospheric methane (CH4) is of importance for both climate change and air quality. Methane is the second most important anthropogenic greenhouse gas after carbon dioxide. It is also significantly affects the tropospheric oxidants (such as OH and ozone) and then affects the cleansing capability of the atmosphere. Factors controlling the methane concentration and its impacts on tropospheric oxidants are still poorly understood. The project proposes to use observations from the surface network and multiple satellite instruments to examine inter-annual variability of atmospheric methane during 1985-2012. We will conduct a nearly 30-year simulation of tropospheric chemistry using historical emission estimates and meteorological reanalysis, and examine the inter-annual variability of OH and its impact on methane concentration and lifetime. We will use surface measurements of methane carbon-13 (C-13) isotope and satellite measurements (SCIAMACHY and GOSAT) to better constrain the methane emissions from different sectors, anthropogenic vs. natural, and their inter-annual variability using the adjoint method and a model simulation of methane C-13 isotope. The project will further investigate impacts of changes in the methane concentration on the inter-annual variability of OH and ozone concentrations in the past 30 years, and quantify the role of methane on climate change and air quality.

英文关键词： air pollution;climate change;methane;adjoint model;carbon isotope