Tracing stratospheric transport using sub-annual plutonium-239 fallout in polar ice cores
Data files
Oct 09, 2025 version files 77.74 KB
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Pu239_icecore_concentration.xlsx
75.36 KB
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README.md
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Abstract
Polar ice cores preserve high-resolution archives of historical atmospheric transport, providing unique insights into long-term stratospheric processes. Here, we present the first sub-annual plutonium-239 (239Pu) deposition records from Greenland and Antarctic ice cores (1940–1980 CE). The limited or delayed fallout from Ivy Mike (1952 CE) compared to Operation Castle (1954 CE), despite their detonation in close proximity, exemplifies how stratospheric circulation and seasonal dynamics create periods of reduced transport to Antarctica. These records also reveal seasonal fallout patterns in Antarctica, with enhanced deposition during austral summers driven by stratosphere-troposphere exchange. Our findings refine the understanding of global aerosol dispersion and offer additional insight for modeling atmospheric processes, including those related to volcanic eruptions and geoengineering.
Dataset DOI: 10.5061/dryad.2rbnzs822
Description of the data and file structure
This dataset contains high-resolution measurements of plutonium-239 concentrations from polar ice cores, used to investigate stratospheric transport processes. The data were obtained from one Greenland ice core (NEEM) and three Antarctic ice cores (GV7, Styx, Hercules Névé) covering the period 1940–1980 CE. Sub-annual resolution sampling and analysis provide records of fallout from atmospheric nuclear weapons tests, revealing seasonal variability, the influence of major tests such as Ivy Mike (1952 CE) and Operation Castle (1954 CE), and the timing of long-range transport to Antarctica.
Files and variables
File: Pu239_icecore_concentration.xlsx
Description: Excel file containing ice-core measurements of 239Pu concentrations, δ18O, and non-sea-salt sulfate (GV7 only), along with depth, year, and analytical uncertainty. Two sample sets are provided for the GV7 core:
- GV7 1st set: Higher-resolution samples (~4.2 cm spacing), used for synchronized δ¹⁸O and ²³⁹Pu analyses.
- GV7 2nd set: Lower-resolution replicate samples (~7.3 cm spacing), used to verify reproducibility and refine flux estimates.
Variables
- Depth (m) – Depth of ice core sample in meters.
- Year (CE) – Calendar year assigned to the sample (decimal year where available).
- δ18O (‰) – Stable oxygen isotope ratio (per mil, ‰, relative to VSMOW), used as a seasonal proxy (where available).
- non-sea-salt sulfate (ppb) – nss-SO42- concentrations (available for GV7 ice core), used for annual layer counting and volcanic synchronization.
- 239Pu (fg g-1) – Concentration of plutonium-239 in femtograms per gram of ice.
- CI (95%) – Analytical 95% confidence interval for 239Pu concentrations.
- bdl – Indicates “below detection limit” values (detection limits vary between 0.037 and 0.15 fg g-1 depending on core).
Access information
Other publicly accessible locations of the data:
- None
Data was derived from the following sources:
- Original measurements of 239Pu concentrations, δ18O, and nss-SO42- were conducted by the authors, as detailed in the associated publication.