BC concentrations and size distributions in the surface snow of Syowa and Mizuho route in 2011

This data set is the concentrations and size distributions of BC and inorganic ions in snow samples collected at the Syowa station in Antarctica from April to December 2011 and along a traverse route to an inland (Mizuho) station (S16, H280 and Mizuho) in October.
The sampling point at the Syowa station was located 400 m east of the main area and 35 m upwind from the "clean air observatory". Samples were collected from surface snows ~1-10 cm in depth using glass containers by the 52nd Japanese Antarctic Research Expedition (JARE52, 2010-2012).
These samples were kept below -20 degreeC until the analyses performed at the National Institute of Polar Research (NIPR) in Japan. Snow samples that were not directly in contact with the inner wall or the lid of the container was crushed using a ceramic knife and distributed to four containers at a class 100 clean booth in the low-temperature laboratory of the NIPR; three glass containers for SP2 analysis and one low-density polyethylene (LDPE) container for inorganic ion analysis. Then, the samples were melted in a refrigerator at 5 degreeC and sonicated for 15 minutes. All tools and containers used for sample handling were sonicated for 15 minutes with acetone and ethanol and then with ultra-pure water.
The mass and number concentrations of BC (CMBC and CNBC) in the snow samples and BC size distributions were analyzed using two modified nebulizer/single particle soot photometer (SP2, Droplet Measurement Technology, Boulder, Colorado, USA) at the NIPR and te Univesity of Tokyo. BC particles were aerosolized by a concentric pneumatic nebulizer (Marin-5, Cetac Technologies Inc., Omaha, Nebraska, USA) at a water flow rate of 3.0 microL s-1 to introduce into the SP2 at a flow rate of 16 cm3 s-1. Inorganic ion concentrations (Cl-, NO2-, Br-, NO3-, SO42-, Na+, NH4+, Mg2+, Ca2+, and K+) were measured using an ion chromatograph (IC-2010, Tosoh, Co., Ltd., Tokyo, Japan). The limit of detection (LOD) values of CMBC for the SP2 analysis were defined as the averaged values of three pure water samples (blank samples), and values of 32.7 ng L-1 and 41.0 ng L-1 were obtained for the SP2/Nebulizer systems at the University of Tokyo and the NIPR, respectively. The LOD values (S/N=3) for cations were 6.1, 17.2, 16.0, 20.3 and 42.3 ppb for Na+, NH4+, Mg2+, Ca2+ and K+, respectively. The LOD values for anions were 4.2, 10.5, 14.5, 8.5 and 17.9 ppb for Cl-, NO2-, Br-, NO3- and SO42-, respectively.
The average CMBC and CNBC between April and November were 288.2 ng L-1 and 101.5 particle mL-1, respectively, and those during December were 2117.3 ng L-1 and 812.7 particle mL-1, respectively. The CMBC and CNBC of the traverse route samples were 1.7 -2.7 times higher than those of the Syowa samples collected during the same period, at 727.7 -1153.2 ng L-1 and 249.6 - 454.6 particle mL-1, respectively. The average mBC was 2.8 (1.8 - 5.8) fg particle-1, which is smaller than typical values in the Arctic. This data was published by Kinase et al. (2019).