长江三角洲地区城市、郊区和乡村下垫面的CO_(2)通量观测  

Measurements of CO_(2) flux over urban,suburban and rural surfaces in Yangtze River Delta region of China

作　　者：邹钧[1,2,3,4] 孙鉴泞 郭维栋[1,2,3] 董新奕 陈辉林[1,2,3] 王海鲲 汪名怀 丁爱军 ZOU Jun;SUN Jianning;GUO Weidong;DONG Xinyi;CHEN Huiin;WANG Haikun;WANG Minghuai;DING Aijun(School of Atmospheric Sciences,Nanjing University,Nanjing 210023;Joint International Research Laboratory of Atmospheric and Earth System Sciences,Nanjing 210023;Jiangsu Provincial Collaborative Innovation Center of Climate Change,Nanjing 210023;Frontiers Science Center for Critical Earth Material Cycling,Nanjing University,Nanjing 210023)

机构地区：[1]南京大学大气科学学院,南京210023 [2]教育部大气与地球系统国际联合实验室,南京210023 [3]江苏省气候变化协同创新中心,南京210023 [4]关键地球物质循环前沿科学中心,南京210023

出　　处：《环境科学学报》2023年第3期281-292,共12页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金重大研究计划项目(No.92044301);国家自然科学基金面上项目(No.42074131);国家自然科学基金青年项目(No.41805007);南京大学关键地球物质循环前沿科学中心“科技人才团队”项目;中央高校基本科研业务费专项资金(No.14380191)。

摘　　要：利用长江三角洲地区南京和苏州两个典型城市的中心城区观测点、南京郊区观测点以及南京市溧水区乡村草地和农田观测点为期一年的CO_(2)通量观测数据,分析不同下垫面之上CO_(2)通量观测值的差异以及城市和郊区不同观测高度的CO_(2)通量观测值的差异.结果表明,城市在CO_(2)地气交换过程中的作用是碳源,而植被下垫面为碳汇;城市粗糙子层中CO_(2)通量观测值随高度增大,上层观测值具有较好的局地代表性;郊区站两个观测高度处于惯性子层之中,CO_(2)通量观测值比较接近,而它们之间的差异则反映了各自高度所对应的不同源区域范围内排放和吸收的不同.依据观测数据估算了不同下垫面的单位面积CO_(2)全年净排放/吸收量,南京和苏州市区全年净排放量分别是18.2 kg·m^(-2)和15.5 kg·m^(-2);农田和草地的全年净吸收量分别是2.9 kg·m^(-2)和0.6 kg·m^(-2);郊区观测点25 m高度所对应的源区域内CO_(2)全年净吸收量为0.5 kg·m^(-2),而50 m高度所对应的源区域内CO_(2)全年净排放量为0.13 kg·m^(-2).This study applied observations collected from five sites to understand CO_(2) fluxes with different underlying surfaces at different heights.CO_(2) fluxes were measured with the eddy-covariance method at two urban sites in Nanjing and Suzhou,one suburban site in Nanjing,and two sites over grassland and cropland of Nanjing,in the Yangtze River Delta of China over 2012—2014.Our results show that barren urban land surface serves as a carbon source while vegetated land surface serves as a carbon sink in the land-atmosphere exchange of CO_(2).We find that the CO_(2) fluxes increase with measurement height in the roughness sublayer,suggesting that measurements at the upper height are more representative than the lower height in land-atmosphere exchange at the local scale.The two suburban sites were both in the inertial sublayer,and their differences in CO_(2) fluxes implied the variations in emissions and sinks of the surroundings.The annual emission and absorption rates of CO_(2) are estimated for different types of underlying surfaces based on these measurements.The emission rates at the two urban sites of Nanjing and Suzhou are 18.2 kg·m^(-2)·a^(-1) and 15.5 kg·m^(-2)·a^(-1),respectively.The absorption rates over the cropland and grassland in rural Nanjing are 2.9 kg·m^(-2)·a^(-1) and 0.6 kg·m^(-2)·a^(-1),respectively.At the suburban site of Nanjing, the measurements at 25 m height suggest an absorption rate of 0.5 kg· m^(-2) · a^(-1), while the measurements at 50m height suggest anemission rate of 0.13 kg·m^(-2)·a^(-1).

关 键 词：长三角 城市 郊区 农田 草地 涡动相关 CO_(2)通量 

分 类 号：X171[环境科学与工程—环境科学] X831