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 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.

The database consists of hourly atmospheric DMS concentrations, daily SO2 and total sulfate concentrations and three-day concentrations of size segregated aerosol sulfate. Samples were taken on the top of the navigation bridge of the CCGS Amundsen as it cruised along Baffin Bay and the Northwest Passage. Hourly samples of DMS was obtained using a customized DMS sampler. Samples were analyzed using a gas chromatograph fitted with a sulfur chemiluminesence detector (GC-SCD) to obtain atmospheric DMS concentrations. SO2 and total aerosol samples were obtained daily using a high volume sampler fitted with a quartz microfiber filter and K2CO3 treated cellulouse filter. Size segragated aerosol samples were obtained using a highvolume sampler fitted with slotted quartz filters on a 5 stage cascade impactor run for three days each sample. Concentrations of SO2, sulfate and MSA as well as other ions from the filter papers were obtained using ion chromatography. Delta34S values of SO2 and sulfate were obtained using a continuous flow isotope ratio mass spectrometer. Delta34S is reported based on the Vienna Canyon Diablo Troillite (V-CDT) international standard.

The database consists of hourly atmospheric DMS concentration, daily SO2 and total sulfate concentrations and three-day concentrations of size segregated aerosol sulfate. Samples were taken on the top of the navigation bridge of the CCGS Amundsen as it cruised along Baffin Bay and Lancaster Sound. Hourly samples of dimethyl sulfide was obtained using a customized DMS sampler. Samples were analyzed using a gas chromatograph fitted with a sulfur chemiluminesence detector (GC-SCD) to obtain atmospheric DMS concentrations. SO2 and total aerosol samples were obtained daily using a high volume sampler fitted with a quartz microfiber filter and K2CO3 treated cellulouse filter. Size segragated aerosol samples were obtained using a highvolume sampler fitted with slotted quartz filters on a 5 stage cascade impactor run for three days each sample. Concentrations of SO2, sulfate and MSA as well as other ions from the filter papers were obtained using ion chromatography. Delta34S values of SO2 and sulfate were obtained using a continuous flow isotope ratio mass spectrometer. Delta34S is reported based on the Vienna Canyon Diablo Troillite (V-CDT) international standard.

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.