研究报告
庞宇婷,徐宏辉,单萌,浦静姣,董一雷.长江三角洲地区CO2浓度本底特征及来源分析[J].环境科学学报,2023,43(2):340-353
长江三角洲地区CO2浓度本底特征及来源分析
- Background characteristics and source analysis of CO2 concentration in the Yangtze River Delta
- 基金项目：国家重点研发计划（No.2020YFA0607502）；浙江省科技厅公益项目（No.LGF22D050004）
- 作者
- 单位
- 庞宇婷
- 浙江省气象科学研究所，杭州 310008;浙江临安大气成分本底国家野外科学观测研究站，杭州 311300
- 徐宏辉
- 浙江省气象科学研究所，杭州 310008
- 单萌
- 浙江省气象科学研究所，杭州 310008;浙江临安大气成分本底国家野外科学观测研究站，杭州 311300
- 浦静姣
- 浙江省气象科学研究所，杭州 310008
- 董一雷
- 浙江省气象科学研究所，杭州 310008;浙江临安大气成分本底国家野外科学观测研究站，杭州 311300
- 摘要：二氧化碳（CO2）是引起全球变暖的最主要的温室气体（GHGs），直接观测大气CO2浓度对于研究人类活动和自然活动对大气温室气体的贡献至关重要，而在多个高度上观测大气CO2浓度则有助于明晰CO2浓度的时空变化规律，确定其影响机制.本文利用临安区域大气本底站2018-12—2020-11不同高度（距地面21 m、53 m）处的CO2在线观测数据，结合日变化及地面风的影响，对观测数据进行筛分，采用 HYSPLIT后向轨迹模型和潜在源贡献因子法，初步探讨气象因素以及大气远距离传输对长江三角洲地区大气CO2浓度的影响.结果表明，临安站高低层大气CO2日变化呈夜间高于白天的特点；低层CO2浓度大于高层，冬季高低层浓度差小于其他三季；日较差呈夏季>春季>秋季>冬季的特点；大气CO2本底季节变化由于受到风向和气团传输的影响呈现出冬季>春季>秋季>夏季的特点；潜在源贡献分析得到浙江省东部的污染源是导致临安站CO2浓度高的重要来源.此外，新冠疫情期间的CO2浓度与往年同期相比有所下降，低层为5.86×10-6（摩尔比，下同），高层为5.67×10-6，新冠疫情使得长三角地区的电力、运输业以及水泥生产部门排放的CO2减少.减少浙江省北部和东部人为排放CO2是降低长三角地区CO2浓度的关键.
- Abstract：Carbon dioxide （CO2） is the most important greenhouse gas that induces the global warming. Direct observation of atmospheric CO2 concentration is vital to assess the contribution of both anthropogenic and natural emissions to the GHGs abundance. The measurement of the atmospheric CO2 concentrations at different heights can help strengthen our understanding of its temporospatial patterns and influencing mechanisms. The two-year （Dec. 2018—Nov. 2020） CO2 online observation data recorded at two heights （21 m and 53 m above the ground） at an atmospheric background station in Lin'an were comprehensively analyzed and discussed. Using the observed diurnal cycles and local meteorological conditions， the background concentrations of CO2 were obtained using the filtering method. Besides， both HYSPLIT backward trajectory model and potential source contribution factor （PSCF） method were adopted to preliminarily investigate the influences of meteorological factors and atmospheric long-range transport on the regional CO2 background concentration. The results show that the atmospheric CO2 at this background station possesses such a diurnal cycle with higher levels during the night than the daytime， vertical distribution with higher concentrations at lower height than the greater height， and its concentration difference between two heights in winter is smaller than those in the other three seasons. The seasonal variation in daily amplitude follows such a descending order： Summer> Spring >Autumn> winter， while the seasonal variation of atmospheric CO2 concentration shows a different order： Winter>Spring>Autumn>Summer， the latter of which could be attributed to the impacts of various wind sectors and air mass origins. PSCF analysis demonstrates that the emission sources in the east of Zhejiang province are the important contributor to the high CO2 levels at the monitoring site. Moreover， the CO2 concentration during the COVID-19 epidemic decreased compared with the same period in previous year by 5.86×10-6（mole ratio， the same below） and 5.67×10-6 in low and high layers respectively， which could be ascribed to the reduced anthropogenic activities such as power， transportation and cement industries， etc. leading to the lesser CO2 emissions in the Yangtze River Delta （YRD） region. Based on the results in this study， it is proposed that to cut the anthropogenic CO2 emissions in the north and east of Zhejiang would be critical to reducing the CO2 concentration in the YRD region.
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