| Summary: | The Arctic region is known to be the most sensitive to climate change. This area is warming two to three times faster than other regions of the world. Clouds represent one of the largest sources of uncertainty in modelling the Arctic response to climate change. It is therefore essential to study the impacts and changes related to the thermodynamic and cloud conditions of the area.<pIn the present work, low-level clouds (below 3000 m) occurrences are investigated within the studied area. We analyze their spatial and seasonal variability over the whole Arctic region. This study is conducted between 60°N and 82°N using active remote sensing observations from CALIPSO/CloudSat satellites. The lidar/radar synergy (DARDAR products) allows to identify cloud phase and to determine cloud occurrences. This unique dataset allows the investigation of cloud variability and its influencing parameters over the whole Arctic region and over several years (2007-2016). Statistical analyses (ACP, multilinear regression and clustering) are used to highlight the influencing parameters of the local and global cloud occurrences.<pWe will present results on time and space variability of clouds over the entire Arctic, and over specific regions. The impact of thermodynamic parameters, sea ice concentration and coupling with surface on cloud phase and occurrence are investigated. On a regional scale, cloud occurrences seem to be correlated with surface conditions. The surface temperature as well as the Lower Tropospheric Stability (LTS) seem to be the predominant influencing parameters. The regionalization shows more pronounced results and trends than for the entire region.
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