Research project
Compositional analysis of Southern high latitude ice-nucleating particles
- Start date: 22 July 2024
- End date: 17 January 2025
- Funder: NERC
- Value: £47,861.28
- Partners and collaborators: British Antarctic Survey
- Primary investigator: Dr Mark D. Tarn
- External primary investigator: Dr. Floor van den Heuvel (British Antarctic Survey)
- Co-investigators: Professor Benjamin Murray
- External co-investigators: Dr Tom Lachlan-Cope (British Antarctic Survey)
Ice-nucleating particles (INPs) are atmospheric aerosols that trigger the freezing of supercooled cloud water droplets and have a significant impact on the lifetime and radiative properties of clouds, in turn influencing weather and climate.
Due to its remoteness, the sources of INPs in Antarctica and the Southern Ocean are believed to be predominantly of natural origin. These can be particles contained in blowing snow, local or long-range transported dust, and biogenic components in sea spray emitted by oceanic processes or by terrestrial biological species. Biological INPs are particularly active as these can nucleate ice at temperatures as high as −2 °C for some bacteria. Very little research has been performed on local sources of Antarctic INPs, although recent studies suggest that the continent could be the source of mineral dust INPs that that was measured in the Southern Ocean.
Although the vast majority of the Antarctic continent is covered by ice sheets, in those areas without ice cover mosses and lichen are abundant. As much as 47% of bryoflora on Alexander Island produce sporophytes, and each sporophyte can produce 5,000-400,000 spores that can be transported over long distances. Given this, it is important to identify and quantify the contribution of bryoflora and lichen to INP populations from Antarctic sources. In a warming climate, this could be an increasingly important source of high-temperature biological INPs over the Southern Ocean.
In this Synergy project between the NERC CloudSense projects, M-Phase (https://cloudsense.ac.uk/m-phase/) and SOC (https://cloudsense.ac.uk/soc/), we will perform compositional analysis of Antarctic INPs to:
1. Identify the composition of airborne ice-nucleating particles (INPs) on the Antarctic peninsula via scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), in order to improve our understanding of the sources of INPs in a region where measurements are sparse and uncertainty in climate models due to INPs and clouds is highest.
2. Compare the compositional analysis of INPs in the Antarctic with the compositional analysis of INPs in the Arctic to better understand the similarities and differences between INP types and sources in the Southern and Northern high latitudes and to determine which INP model parameterisations and uncertainties are, and which are not, transferable between these regions.
3. Start building up a database of SEM-EDS produced high-resolution images of individual particles.
4. Allow for knowledge exchange for INP sampling and analysis strategies for the upcoming SOC cruise in 2024.