CAMP: a balloon-borne platform for aerosol particle studies in the lower atmosphere

• Main Authors: Pilz, Christian, Düsing, Sebastian, Wehner, Birgit, Müller, Thomas, Siebert, Holger, Voigtländer, Jens, Lonardi, Michael
• Format: Text
• Language: English
• Published: 2022
• Subjects: Arctic; Camp A
• Online Access: https://doi.org/10.5194/amt-2022-175; https://amt.copernicus.org/preprints/amt-2022-175/

Airborne observations of vertical aerosol particle distributions are crucial for detailed process studies and model improvements. Tethered balloon systems represent a less expensive alternative to aircraft to capture shallow atmospheric boundary layers (ABL). This study presents the newly developed cubic aerosol measurement platform (CAMP) for balloon-borne observations of aerosol particle microphysical properties. With an edge length of 30 cm and a weight of 9 kg, the cube is an environmentally robust instrument platform intended for measurements at low temperatures, with a particular focus on applications in cloudy Arctic ABLs. The aerosol instrumentation onboard CAMP comprises two condensation particle counters with different lower detection limits, one optical particle size spectrometer, and a miniaturized absorption photometer. Comprehensive calibrations and characterizations of the instruments were performed in laboratory experiments. The first field study with a tethered balloon system took place at the TROPOS research station in Melpitz, Germany, in the winter of 2019. At ambient temperatures between -10 and 15 °C, the platform was operated up to 1.5 km height on 14 flights under a clear sky and cloudy conditions. The continuous aerosol observations at the ground station served as a reference for evaluating the CAMP measurements. During two subsequent balloon flights on the late morning of 15 February, descending layers with increased concentrations of nucleation mode particles were observed above a shallow well-mixed surface layer separated by a weakening temperature inversion. A subsequent increase in nucleation mode particles on the ground after the balloon flights suggests a downward mixing of the particles. Based on the laboratory instrument characterizations and the observations during the field campaign, CAMP demonstrated the capability to provide comprehensive aerosol particle measurements in cold and cloudy ABL.