Abstract This paper presents the climatology of aerosol optical properties and radiative forcing over the Arctic obtained within the framework of the iAREA (impact of absorbing aerosols on radiative forcing in the European Arctic) project. The presented data were obtained from the Navy Aerosol Analysis and Prediction System (NAAPS) and the Fu-Liou radiative transfer model. NAAPS was used to simulate particle concentration and aerosol optical depth (AOD) at 1 ° × 1 ° spatial resolution. Direct aerosol radiative forcing (ARF) was calculated for clear-sky and all-sky conditions based on NAAPS reanalysis (with AOD assimilation) and satellite observations of surface and cloud properties. Long-term data (2003–2015) from NAAPS show that anthropogenic and biogenic aerosol, as well as sea salt, make the most important contribution to total AOD (35 and 30%, respectively). However, smoke (15%) and mineral dust (20%) cannot be neglected, especially during spring and summer. Results of numerical simulations indicate mean shortwave (SW) ARF for the whole Arctic (>70.5oN) at the Earth's surface to be −4 W/m2 for clear-sky and −1.3 W/m2 for all-sky conditions, and at top of the atmosphere (TOA) −1.3 W/m2 and -0.4 W/m2, respectively. TOA ARF for anthropogenic and biogenic particles is only −0.1 W/m2 for clear-sky and almost zero for all-sky conditions. For smoke and dust particles, SW ARF is very similar for both Earth's surface and TOA, as well as for clear-sky and all-sky conditions. For sea salt, SW ARF is the same at the surface and at TOA: 0.6 W/m2 for clear-sky and −0.3 W/m2 for all-sky conditions, because of negligible solar absorption. Cloud cover reduces surface cooling (direct clear-sky SW ARF) by a factor of 40% and shifts TOA SW ARF towards positive values.

中文翻译：

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在 iAREA 项目框架内模拟北极上空的长期直接气溶胶辐射强迫

摘要 本文介绍了在 iAREA（吸收气溶胶对欧洲北极辐射强迫的影响）项目框架内获得的北极气溶胶光学特性和辐射强迫的气候学。所提供的数据来自海军气溶胶分析和预测系统 (NAAPS) 和 Fu-Liou 辐射传输模型。NAAPS 用于模拟 1°×1° 空间分辨率下的粒子浓度和气溶胶光学深度 (AOD)。直接气溶胶辐射强迫 (ARF) 是根据 NAAPS 再分析（使用 AOD 同化）和卫星观测表面和云特性计算晴空和全天条件的。NAAPS 的长期数据（2003-2015 年）表明，人为和生物气溶胶以及海盐对总 AOD 的贡献最大（35% 和 30%，分别）。然而，烟雾（15%）和矿物粉尘（20%）也不容忽视，尤其是在春季和夏季。数值模拟结果表明，地球表面整个北极 (>70.5oN) 的平均短波 (SW) ARF 在晴空条件下为 -4 W/m2，在全天条件下为 -1.3 W/m2，并且在顶部大气 (TOA) 分别为 -1.3 W/m2 和 -0.4 W/m2。人为和生物颗粒的 TOA ARF 在晴空条件下仅为 -0.1 W/m2，在全天条件下几乎为零。对于烟尘颗粒，SW ARF 对于地球表面和 TOA 以及晴空和全天条件都非常相似。对于海盐，表面的 SW ARF 和 TOA 的 SW ARF 相同：晴天为 0.6 W/m2，全天条件为 -0.3 W/m2，因为太阳吸收可以忽略不计。