Aerosols and clouds play important roles in the Arctic climate. Conversely, aerosol emissions and cloud formation are affected by changes in the Arctic climate. This paper reviews studies of aerosols and clouds performed during the Arctic Challenge for Sustainability (ArCS) project carried out by the National Institute of Polar Research (NIPR) in Japan and collaborating institutions. The ArCS project included intensive studies of black carbon aerosols (BC). We installed Continuous Soot Monitoring System (COSMOS) instruments to measure atmospheric BC at four locations in the Arctic, establishing the Arctic BC COSMOS Measurement Network (ABCM-net). We also measured BC concentrations in snowpack in extensive areas of the Arctic and showed that previous studies have greatly overestimated BC in snowpack. We developed and improved new aerosol models that achieved better agreements with measurements of BC in the Arctic atmosphere, snowpack, and falling snow. We made new estimates of radiative forcing of BC in the Arctic atmosphere and snow/ice surfaces that lower their albedo. In addition to these researches on BC, we made accurate measurements of ice nucleating particles (INPs) at Ny-Ålesund, Svalbard, showing that their concentrations increased in summer as a result of dust particle emissions from glacial outwash sediments. This high ice nucleating ability was likely due to the presence of organic substances mixed with the dust particles. We also made continuous cloud radar measurements and the first continuous in-situ measurements of cloud microphysical properties in the Arctic at Ny-Ålesund. Results from these cloud measurements and their relationship with aerosols are described.

气溶胶和云在北极气候中起着重要作用。相反，气溶胶的排放和云的形成受北极气候变化的影响。本文回顾了日本国立极地研究所（NIPR）和合作机构在“北极可持续性挑战（ArCS）”项目中进行的气溶胶和云的研究。ArCS项目包括对黑碳气溶胶（BC）的深入研究。我们在北极的四个位置安装了连续烟尘监测系统（COSMOS）仪器，以测量大气中的BC，并建立了BCBC COSMOS测量网络（ABCM-net）。我们还测量了北极广大地区积雪中的BC浓度，并表明先前的研究大大高估了积雪中的BC。我们开发并改进了新的气溶胶模型，该模型与北极大气，积雪和落雪中的BC测量值达成了更好的协议。我们对北极大气和降雪反照率的雪/冰表面中的BC辐射强迫进行了新的估算。除了在卑诗省进行的这些研究以外，我们还对斯瓦尔巴特群岛Ny-Ålesund的冰核颗粒（INPs）进行了精确测量，结果表明，由于冰川冲积沉积物排放的尘埃颗粒，夏季它们的浓度增加了。如此高的冰成核能力可能是由于有机物质与粉尘颗粒混合而造成的。我们还进行了连续的云雷达测量，并首次在Ny-Ålesund进行了北极云微物理特性的连续原位测量。