The scientific expedition VERDI (short for Vertical Distribution of Ice in Arctic Clouds) is a cooperation project of various German research institutes with the goal to measure the microphysical and optical properties of Arctic boundary-­layer clouds, and to investigate the effects that those clouds can have on the energy budget in the Arctic atmosphere. The VERDI participants have successfully performed airborne measurements of the microphysical and radiative properties of clouds in the Canadian Arctic (based in the town of Inuvik in the Northwest Territories) in April and May 2012, and are now working on the data processing and evaluation. At least seven publications on VERDI results (listed below) are planned, and it is desired to bundle these in the planned ACP/AMT inter-­journal special issue. The special issue is open for all submissions within its scope.