CleanCloud CHOPIN - radar data & code

This repository contains the code & data referenced in the ESSD manuscript "Multi-frequency radar measurements of clouds and precipitation collected during the 2024-2025 CHOPIN campaign at Mt. Helmos". Manuscript abstract: This article describes the dataset of cloud and precipitation measurements collected during the CleanCloud Helmos OrograPhic sIte experimeNt (CHOPIN) campaign, conducted from October 2024 to January 2025 on Mt. Helmos, Peloponnese, Greece. The data were collected by the Environmental Remote Sensing Laboratory of the École Polytechnique Fédérale de Lausanne (EPFL) and comprise coordinated observations from X- and Ka-band dual-polarisation Doppler radars and a W-band Doppler cloud profiler, complemented by 37 radiosonde profiles. Precipitation occurred for approximately 440 hours, resulting in roughly 1.2 m of snow accumulation at the remote sensing site. Two precipitation events are presented to illustrate the two main cloud and precipitation regimes captured in the dataset. The first event, between 6 and 8 January 2025, captures a succession of shallow turbulent orographic clouds interspersed with higher non-precipitating clouds, with a brief episode of surface-reaching precipitation from the upper cloud layer. The second case study, on 15 January 2025, shows a mixed-phase precipitation system dominated by primary ice nucleation near cloud top, particle growth through deposition and aggregation, and signatures of riming in the lower cloud layers, within a dynamically evolving synoptic context. Together, these examples highlight the potential of multi-frequency radar observations in an orographic winter setting for investigating cloud microphysics, particle growth processes, and aerosol--cloud interactions in mixed-phase clouds. As a dataset combining wintertime orographic conditions with coordinated multi-frequency radar observations, and collected alongside an extensive suite of in situ cloud microphysical and aerosol measurements within the broader CleanCloud campaign, the CHOPIN radar data opens new possibilities for mixed-phase cloud microphysics and aerosol-cloud interaction studies.