CCA3: Arctic mixed-phase clouds

Mixed-phase clouds in the Arctic are still poorly represented in climate models. Their role for Arctic amplification needs further research. A potential domain for the ICON-LAM forcing simulation including the three observational supersites [Utqiagvik (NSA), RV Polarstern (PS), and Ny-Ålesund (NYA)]. On the right an example for the observed radar relectivity and an ICON-LEM setup including the topography around Ny-Ålesund. Similar setups will be used for high-resolution simulations around the other two super-sites all forced by the ICON-LAM.

• Investigate mixed-phase clouds across Arctic using airborne measurements and data collected at different Arctic regions: Ny-Ålesund in Eurasian Arctic, Utqiagvik (Barrow) in western Arctic, and RV Polarstern in central Arctic,
• Point measurements will be complemented by airborne observations [MOSAiC and HALO-(AC)³], which cover larger areas and provide useful insights into evolution of Arctic air masses,
• Combining the different observational data sets with simulations by ICON model family, allows to assess representativity of cloud parameterisations across the Arctic and influence of different surface conditions,
• Involve large spectrum of scales for mixed-phase by placing a special focus on the impact of certain microphysical processes at different scales.

• How do regional differences influence the representation of mixed-phase clouds in the coarse and fine model simulations? What is the relative impact of changing surface and synoptic conditions (link to CCA2 and CCA4)?
• Are there differences in the model and/or the observations of mixed-phase clouds depending on the air masses these clouds are formed in (link to CCA4)?
• Which processes and heterogeneities are key to be represented in models, and do they differ across the different sites? What is the impact of changes in cloud phase on cloud radiative effects (link to CCA1)?

• Chain from observations and high-resolution simulation up to weather and climate models as consistent as possible,
• Comparison at process level between observations and high-resolution simulations will enable a detailed assessment of microphysical parameterisations on necessary scales,
• Due to the consistent forcing, a focus on microphysics will be possible and gained insight will be transferred back to larger scale models,
• Collaboration will be established by bringing together projects performing  measurements from surface and across-scales from aircraft and those performing ICON simulations.