The Arctic is warming more rapidly than the rest of the globe. While sea ice-albedo feedback appears to be a clear factor, the roles by other processes are still difficult to quantify. In particular, contributions from forcing and feedback mechanisms associated with clouds and aerosols remain uncertain. Black carbon (BC) aerosols produced by fossil and biofuel combustion and biomass burning are transported to the Arctic region and deposit on snow/ice. They efficiently absorb solar radiation, potentially leading to an acceleration of ice-albedo feedback. However, there are still large uncertainties in their abundances in the atmosphere, size distribution, mixing state, and deposition processes to the surface. Clouds in the Arctic are also poorly characterized especially over the Atlantic sector. Mixed-phase clouds persistently appear in the Arctic lower troposphere. In addition, it has been reported that numerical model calculations of mixed-phase clouds are generally quite sensitive to concentrations of ice nucleating particles (INPs). However, there are still large uncertainties in number concentrations, chemical composition, and sources of INPs. These considerations give a strong motivation for studying cloud-aerosol radiation processes in Ny-Ålesund as part of a Japanese Arctic region research project, called ArCS (Arctic Challenge for Sustainability). Ny-Ålesund is an ideal site due to rich data sets being obtained by international research activities. During the previous Japanese Arctic region research project (GRENE project, 2011-2016), continuous in-situ measurements of BC mass concentration and cloud microphysical properties were started at the Zeppelin Observatory. Measurements of vertical profiles of clouds and aerosols were also started in the Ny-Ålesund village using a 95 GHz Doppler cloud radar and micro pulse lidar with polarization capability. In addition to these measurements, we will perform more detailed analyses of BC and other particles in the atmosphere and snow. We will also evaluate the impact of these aerosols on ice nucleation processes in Arctic mixed-phase clouds based on in-situ measurements at the Zeppelin Observatory.

02:39 on Tue January 14, 2020