The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition was an international initiative in which research vessel (R/V) Polarstern drifted with the sea ice in the Central Arctic Ocean from October 2019 to September 2020. Here, we present data from a study in which Beryllium-7, a naturally occurring radioactive isotope with a half-life of 53 days, is used as a tracer for the atmospheric deposition of trace elements to the ocean / ice surface and their partitioning among the seawater, ice and snow catchments during winter and spring. The data sets include measurements of Be-7 in 1) aerosol particles collected on filters using a high volume sampler on Polastern, 2) seawater from the upper water column (8-60 meters depth) collected using the ship’s seawater intake system and using pumps on the ice floe, and 3) ice cores, snow, and frost flowers collected from sites on the MOSAiC and surrounding ice floes. Be-7 analysis was performed using high purity germanium gamma detectors.
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This content will become publicly available on February 21, 2025
Aerosol Deposition and Snow Accumulation Processes From Beryllium‐7 Measurements in the Central Arctic Ocean: Results From the MOSAiC Expedition
We use a tracer method involving the cosmogenic radioisotope beryllium‐7 (half‐life = 53.3 days) to follow the deposition of aerosols and the fate of snow on the MOSAiC ice floe during winter and spring 2019–2020. When examined alongside data from earlier studies in the Arctic Ocean that covered summer and fall, Be‐7 inventories indicate a summertime peak for aerosol Be‐7 deposition fluxes coinciding with seasonal minima boundary‐level aerosol concentrations, which suggests that deposition fluxes are primarily controlled by precipitation. This conclusion is supported by the linear relationship between Be‐7 fluxes and precipitation rates derived from data from the MOSAiC and SHEBA expeditions. Inventories of Be‐7 within the snow column exhibited evidence of significant redistribution. Be‐7 deficits, relative to the flux, were observed in areas of level sea ice while excess Be‐7 was found associated with deformed ice features such as pressure ridges, leading to the following estimates for the distribution of snow on the ice floe in May 2020: 75–93% of the snow mass is found on deformed sea ice with the remainder on level ice. Furthermore, uncertainties associated with measurements of Be‐7 concentrations within the ocean mixed layer would allow for losses of snow through open leads of up to approximately 20% of the flux. Our snow distribution estimates agree with data from repeat snow depth transect measurements. These results suggest that Be‐7 can be a useful tool in studying snow redistribution.
more » « less- NSF-PAR ID:
- 10492270
- Publisher / Repository:
- American Geophysical Union
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Oceans
- Volume:
- 129
- Issue:
- 2
- ISSN:
- 2169-9275
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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