11:00 AM - 1:00 PM
[AAS11-P17] Observation for Arctic marine aerosol during Mirai cruise in 2021
Keywords:Arctic, Aerosol, Marine
Climate change is one of the most important issues for the Earth's future. Especially, in the Arctic region, the temperature rapidly rose by 2.7–3.1 °C during the period between 1971 and 2017 (Box et al., 2019). This temperature increase possibly affects the global system such as the global ecosystem (Pecl et al., 2019). Therefore, research for Arctic climate change is important. Aerosol significantly contributes to climate change via effects on the radiation and cloud properties. However, the measurement of Arctic aerosol is not sufficient, especially in the marine environment. To understand the Arctic climate change in detail, observations for the time and spatial distribution of various aerosols, their existing states, and the estimation for effects of long-range transports are required. Our group conducted various aerosol online measurements and samplings throughout the Arctic cruise of R/V Mirai (MR21-05C) in 2021. In this presentation, we introduce the observational results of these online measurements and electron microscopic (EM) analysis.
This observation was done between September and October in 2021 from Shimizu port to the Arctic ocean (approximately 75° of the Alaskan side). As online measurements, we observed concentrations of BC mass (SP2 model-D, Droplet Measurement Technologies (DMT)), the size distributions of fine (Nano Scan model 3910, TSI) and coarse mode particles (KR-12A, Rion), fluorescent particles (WIBS-4A, DMT), CO (48i-TLE, Thermo Fisher Scientific), O3 (model 205, 2B Technologies), and the aerosol extinction coefficient (MAX-DOAS). The observations of WIBS-4A and KR-12A were done on the compass deck to avoid particle loss on the sampling tubes. In addition, a two-stage auto impactor was equipped at the laboratory with sampling intervals of between one to four hours for the electron microscopic analysis. On the compass deck, aerosol samplings by a single stage impactor (TE-231, Tisch Environmental) with quartz fiber filters using a high volume air sampler (120SL, Kimoto electric) and by a nuclepore membrane filter for the ice nuclei particle measurement with the interval times of two days. These aerosol samplings were controlled by the wind selector which was equipped with an anemometer to avoid contamination from Mirai. In addition, a three stages impactor (MPS-3, California measurement) with Cu grids was used for the irregular aerosol sampling for the EM analysis (between one to four times each day).
The fine particle (10-400 nm) and BC concentrations were relatively high over the Pacific ocean (Figures (a) and (b)) ; on the other hand, they largely decreased in the Bering and the Arctic ocean. However, several increases in the BC and the fine particle concentrations were also observed (Figure (a) and (b)) , indicating various events such as BC transports from the remote sources and aerosol particle growth. As an example of the aerosol transport events, several tarball particles were actually found from the samples with which influences of biomass burning were suggested with the model calculation (Figure (c)) . In addition, the changes of sulfate particle states (possibly sulfate) with samples that were collected in the period of particle growth occurred.
Figure. Spatial distribution for the concentration of (a) BC mass and (b) fine particle numbers that were observed during the whole observation period. (c) An example of a tarball particle which was observed by a transmission electron microscope.
This observation was done between September and October in 2021 from Shimizu port to the Arctic ocean (approximately 75° of the Alaskan side). As online measurements, we observed concentrations of BC mass (SP2 model-D, Droplet Measurement Technologies (DMT)), the size distributions of fine (Nano Scan model 3910, TSI) and coarse mode particles (KR-12A, Rion), fluorescent particles (WIBS-4A, DMT), CO (48i-TLE, Thermo Fisher Scientific), O3 (model 205, 2B Technologies), and the aerosol extinction coefficient (MAX-DOAS). The observations of WIBS-4A and KR-12A were done on the compass deck to avoid particle loss on the sampling tubes. In addition, a two-stage auto impactor was equipped at the laboratory with sampling intervals of between one to four hours for the electron microscopic analysis. On the compass deck, aerosol samplings by a single stage impactor (TE-231, Tisch Environmental) with quartz fiber filters using a high volume air sampler (120SL, Kimoto electric) and by a nuclepore membrane filter for the ice nuclei particle measurement with the interval times of two days. These aerosol samplings were controlled by the wind selector which was equipped with an anemometer to avoid contamination from Mirai. In addition, a three stages impactor (MPS-3, California measurement) with Cu grids was used for the irregular aerosol sampling for the EM analysis (between one to four times each day).
The fine particle (10-400 nm) and BC concentrations were relatively high over the Pacific ocean (Figures (a) and (b)) ; on the other hand, they largely decreased in the Bering and the Arctic ocean. However, several increases in the BC and the fine particle concentrations were also observed (Figure (a) and (b)) , indicating various events such as BC transports from the remote sources and aerosol particle growth. As an example of the aerosol transport events, several tarball particles were actually found from the samples with which influences of biomass burning were suggested with the model calculation (Figure (c)) . In addition, the changes of sulfate particle states (possibly sulfate) with samples that were collected in the period of particle growth occurred.
Figure. Spatial distribution for the concentration of (a) BC mass and (b) fine particle numbers that were observed during the whole observation period. (c) An example of a tarball particle which was observed by a transmission electron microscope.