Tracing stratospheric transport using sub-annual plutonium-239 fallout in polar ice cores

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.
, , # Tracing stratospheric transport using sub-annual plutonium-239 fallout in polar ice cores

Dataset DOI: [10.5061/dryad.2rbnzs822](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 ^239^Pu concentrations, δ^18^O, and non-sea-salt sulfate (GV7 only)...,