This dataset comprises a large-sample collection of over 500 vertical dropsonde profiles collected during three Arctic aircraft campaigns, which were embedded in the framework of the Transregional Collaborative Research Center called Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms ((AC)³). The measurements were collected with the Polar 5 and the High Altitude and LOng Range Research Aircraft (HALO) during the Arctic Amplification: FLUXes in the Cloudy Atmospheric Boundary Layer (AFLUX, March/April 2019), the HALO-(AC)³ (March/April 2022) , and the Clouds over Complex Environments EarthCARE (COMPEX-EC) (April 2025) campaign. All dropsonde profiles were recorded in the Fram Strait region, primarily over the open ocean during spring, which is a key period for observing Arctic Cold Air Outbreaks (CAOs). The data is an extension of the original dropsonde measurements (air temperature, humidity, pressure, and horizontal wind vector). Each dropsonde profile has been interpolated to a consistent vertical grid (surface to 3 km, 5 m resolution) and enhanced with several derived parameters critical for the analysis of boundary layer stability and cloud organization:Marine CAO Index (M-Index): A measure of atmospheric instability, calculated from the potential temperature difference between the sea surface and the 850 hPa level.Stability Parameter (−H/L): The negative ratio of the boundary layer height (H) to the Monin-Obukhov length (L), which is used to classify the relative influence of buoyancy and shear on turbulent generation.Cloud Regime Classification: A consensus-based classification of the cloud structure (e.g., Cloud streets, Isotropic clouds, Open cells) present at the dropsonde location, derived from MODIS satellite imagery.This combined and extended dataset was used to validate the stability parameter as a predictor for cloud regimes in CAOs. This dataset is presented in Klingebiel et al. (2026).