| 摘要: |
| 本研究利用MERRA-2再分析数据和CMIP6模式DAMIP实验数据, 分析了近40 a北极气溶胶的时空变化特征及其对地表向下短波辐射的影响。研究结果表明, 北极气溶胶光学厚度整体呈持续下降趋势, 但下降速率逐渐减缓; 北极气溶胶光学厚度下降速率明显高于中低纬度陆地区域。北极气溶胶组分表现出显著的季节性和区域性差异: 黑碳气溶胶和有机碳气溶胶浓度在春夏季较高, 主要受远距离传输和生物活动驱动; 沙尘气溶胶在春季因风力增强和沙尘暴活动频繁而显著增加; 硫酸盐气溶胶则在春季和冬季占主导, 与工业排放及大气化学反应密切相关。楚科奇海区域气溶胶浓度普遍高于其他北极海域, 而格陵兰岛因地势高和冰盖覆盖而呈现低值特征。晴空条件下气溶胶光学厚度与向下短波辐射呈强负相关, 其辐射强迫效应在夏季最为显著(R= -0.72)。晴空条件下MERRA-2、CMIP6历史情景和只有人类排放气溶胶强迫Hist-aer实验的北极区域平均的大气层对向下短波辐射的削弱比例分别为30%、28%和27%。由于辐射传输过程中穿过大气的几何路径对气溶胶效应的影响, MERRA-2再分析数据和CMIP6模式都表现出北极高纬度地区辐射削弱比例偏高的现象。 |
| 关键词: 北极 气溶胶 短波辐射 MERRA-2 晴空条件 CMIP6 |
| DOI：10.11759/hykx20250414001 |
| 分类号:P73 |
| 基金项目:国家自然科学基金项目(42276254); 国家重点研发计划项目(2017YFA0604602) |
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| Temporal and spatial variations of Arctic aerosol and its influence on downward shortwave radiation |
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Yan Yangtian, Bai Xuezhi
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College of Oceanography, Hohai University, Nanjing 210024, China
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| Abstract: |
| Based on reanalysis data from the modern-era retrospective analysis for research and applications, version 2 (MERRA-2) and experimental data from the Coupled Model Intercomparison Project Phase 6 (CMIP6) Detection and Attribution Model Intercomparison Project (DAMIP), the temporal and spatial variations of Arctic aerosols over the past 40 years and their influence on surface downward shortwave radiation are analyzed. The results reveal that Arctic aerosol optical depth (AOD) shows a continuous but gradually decreasing trend, with a decline rate significantly higher than that in middle and low latitudes. The composition of Arctic aerosol shows significant seasonal and regional differences: the concentrations of black and organic carbon are higher in spring and summer, mainly driven by long-distance transport and biological activities; dust levels increase significantly in spring due to stronger winds and frequent sandstorm activities. Sulfate dominates in spring and winter, correlating closely with industrial emissions and atmospheric chemical reactions. Aerosol concentration in the Chukchi Sea is generally higher than in other Arctic waters, whereas Greenland is characterized by low concentrations because of its high terrain and ice cover. A strong negative correlation exists between AOD and downward shortwave radiation in clear skies, and its radiation forcing effect is most significant in summer (r = -0.72). The average atmospheric attenuation ratios of downward shortwave radiation in the MERRA-2 and CMIP6 historical scenarios under clear skies and obtained from a hist-aer experiment in the Arctic region are 0.31, 0.28, and 0.27, respectively. Due to the influence of the geometric path of radiation through the atmosphere on aerosol effects, MERRA-2 reanalysis data and the CMIP6 model display a phenomenon where the radiation attenuation ratios intensify at high Arctic latitudes. |
| Key words: Arctic aerosol shortwave radiation MERRA-2 clear-sky CMIP6 |
