Raw backscatter data were collected from a CT25K ceilometer. A ceilometer is a device that uses a laser or other light source to determine the height of a cloud base. Ceilometers can also be used to measure the aerosol concentration within the atmosphere. Sampling took place from July to November 2009 in the southern Beaufort Sea and the Amundsen Gulf (Canadian Arctic) during the CFL cruise onboard the CCGS Amundsen icebreaker. The Circumpolar Flaw Lead System Study (CFL) is an IPY-funded project. Data were collected (1) during the ship transit, (2) set transects, (3) at several stations where we stayed 24 hours, and (4) at multi-day drift stations. The instrument was running continuously during the CFL project, with only minor interruptions for maintenance activities.

Raw backscatter data were collected from a Vasaila CT25K ceilometer. A ceilometer is a device that uses a laser or other light source to determine the height of a cloud base. Ceilometers can also be used to measure the aerosol concentration within the atmosphere. Sampling took place from in the Southern Beaufort Sea and the Amundsen Gulf (Canadian Arctic) during the ArcticNet / BP Partnership cruise onboard the CCGS Amundsen. Data were collected (1) during the ship transit, (2) set transects, (3) at several stations where we stayed 24 hours, and (4) at multi-day drift stations. The instrument was running continuously during the cruise, with only minor interruptions for maintenance activities.

Raw backscatter data were collected from a CT25K ceilometer. A ceilometer is a device that uses a laser or other light source to determine the height of a cloud base. Ceilometers can also be used to measure the aerosol concentration within the atmosphere. Sampling took place from May to October 2016 in the Beaufort Sea, Northwest Passage, Baffin Bay (Canadian Arctic) during the cruise onboard the CCGS Amundsen icebreaker. The CT25K is designed to detect three cloud layers simultaneously up to around 18 000 ft, given suitable conditions. Besides cloud layers, it detects whether there is precipitation or other obstruction to vision. Output files were created hourly by the system and are in ASCII format.

Real-time atmospheric measurements were made on board the CCGS Amundsen. Sampling lines were placed on the forward mast of the ship, and instruments were housed in a sampling shed located on the top deck. Mixing ratios of volatile organic compounds (VOCs: dimethylsulfide, acetone, methanol, benzene, etc.) were measured using proton-transfer-reaction mass spectrometry. Aerosol size distributions between 10 and 500 nm were measured using a scanning mobility particle sizer and total aerosol number concentrations > 3 nm were measured using an ultrafine condensation particle counter. All data have time resolution of minutes.