Methodology:

To measure airborne snow particles Snow Particle Counters (SPC) (SPC-95, Niigata Electric Co., Ltd) were employed manufactured and calibrated in Japan. The open-path SPC has a wind vane to steer into the prevailing wind direction and is equipped with a super-luminescent diode sensor, which acts as a constant light source during the measurement. Once a snow particle enters the beam first the light energy detected by the upwind sensor decreases then that seen by the down-wind sensor. These signals are converted to two successive voltage pulses, which are proportional to particle size. Each signal is classified into one of 64 size classes (30 to 500 μm particle diameter). The SPC measures number flux of snow particles within each size class. Number flux can be converted into number concentration or drift density by dividing by horizontal wind speed from the nearest wind speed sensor on the mast (Level 2.4 NOAA doi:10.18739/A2K649V1F). The project was part of the international Multi-disciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) with the tag MOSAiC20192020.

The latitude/longitude indicate the spatial bounds of the MOSAiC ice floe drift during the period covered by the entire dataset (October 2019 to July 2020).

Data collection:

Instrumentation used: Snow Particle Counters SPC-95 (Niigata Electric Co., Ltd)

Data quality:

The two SPC units (Unit 1104 at 0.08 m; Unit 1206 at 10 m) did run near-continuously from Oct 2019 until the end of Jul 2020, except during power cuts during March to May, and when the ice floe was abandoned for 5 weeks from mid-May 2020. SPC Unit 1104 started recording only from 2 Dec 2019. Calibrations were done for Unit 1104 on 19.06.2019 and for Unit 1206 on 26.09.2012. Unit 1206 showed occasionally malfunctioning: i) spurious small particle increases in the absence of drifting snow or precipitation, and ii) size spectra were clipped at the smaller sizes. In this data version no data were removed.