Themed collection Atmospheric chemistry in cold environments - Topic Highlight

Different processes can lead to high electrical field strengths in snow and ice in polar regions with the potential to initiate free radical processes and a number of other chemical modifications.

During the last several decades, numerous researchers have provided evidence that physical and biogeochemical processes at air-snow/ice-water interfaces are very complex, and, in many cases, interlinked.

Schematic of the proposed deposition ice nucleation mechanism on AgI (0001).

Ice nucleating particles (INPs) in sea spray aerosol (SSA) are important for ice formation in clouds over oceans. We found that SSA INP concentrations during a phytoplankton bloom were degraded with exposure to 3 to 8 days of atmospheric oxidation.

Oceans emit ice-nucleating particles (INPs) which freeze supercooled cloud droplets, modifying clouds. We added dead biomass of three phytoplankton to seawater. Each time, this stimulated INP production in the water and INP emissions in sea spray.

Amorphous ice plays an important role in our overall understanding of water's phase diagram.

We use simulated droplet freezing experiments to probe the impact of variability in ice nucleation propensities (represented as differently-shaped distributions), and observe differences at low frozen fractions and for broad distributions.

Airborne dust from the Kaskawulsh Glacier outwash sediments contains effective INPs. The concentrations and properties of the INPs were investigated.

Ice nucleation can now be imaged in situ using X-ray spectro-microscopy in a new experiment, which is applied to mineral aerosol particles composed of ferrihydrite or feldspar and associated organic matter.

A robust sample handling, processing and analytical method was developed for reliable determination of 40 TEs in dusty snow. The “dissolved” TEs in snow from the ABS region were extremely low, and TEs were almost exclusively found in the particulate fraction.

Our results suggest that a significant source of ice nucleating particles at Alert, Nunavut, during October and November, was likely ice-free and snow-free land at latitudes >50 °N.

The ice nucleation activity of volcanic ash can change when exposed to liquid water or aqueous sulfuric acid through a complex interplay of geochemical alteration mechanisms.

Mineral dust is responsible for the ice-nucleating properties of aerosol samples collected over the British Isles below ∼−20 °C, while an additional source, potentially biogenic, must explain the ice-nucleating properties at higher temperatures.