We developed a model to simulate the natural convection of water within frozen rock crevices subject to daily warming in mountain permafrost regions. Traditional models relying on conduction and latent heat flux typically overlook free convection. The results reveal that free convection can significantly accelerate the melting rate by an order of magnitude compared to conduction-based models. Our results are important for assessing the impact of climate change on mountain infrastructure.

We constructed a box model to evaluate the isotope effects of atmosphere–snow water vapor exchange at Dome A, Antarctica. The results show clear and invisible diurnal changes in surface snow isotopes under summer and winter conditions, respectively. The model also predicts that the annual net effects of atmosphere–snow water vapor exchange would be overall enrichments in snow isotopes since the effects in summer appear to be greater than those in winter at the study site.

We use a numerical ice-flow model to simulate the response of a 1940s Pine Island Glacier to changes in melting beneath its ice shelf. A decadal period of warm forcing is sufficient to push the glacier into an unstable, irreversible retreat from its long-term position on a subglacial ridge to an upstream ice plain. This retreat can only be stopped when unrealistic cold forcing is applied. These results show that short warm anomalies can lead to quick and substantial increases in ice flux.

The simulation of the ice phenology of Nam Co by WRF is investigated. Compared with the default model, improving the key lake schemes, such as water surface roughness length for heat fluxes and the shortwave radiation transfer for lake ice, can better simulate the lake ice phenology. The still existing errors in the spatial patterns of lake ice phenology imply that challenges still exist in modelling key lake and non-lake physics such as grid-scale water circulation and snow-related processes.

As many boreal and alpine forests have seasonal snow, models are needed to predict forest snow under future environmental conditions. We have created a new forest snow model by combining existing, very detailed model components for the canopy and the snowpack. We applied it to forests in Switzerland and Finland and showed how complex forest cover leads to a snowpack layering that is very variable in space and time because different processes prevail at different locations in the forest.

Glaciers that exist within tropical regions are vital water resources and excellent indicators of a changing climate. We use satellite imagery analysis to detect the boundary between snow and ice on the Quelccaya Ice Cap (QIC), Peru, which indicates the ice cap's overall health. These results are analyzed with other variables, such as temperature, precipitation, and sea surface temperature anomalies, to better understand the factors and timelines driving the ice retreat.

Liquid veins and grain boundaries in ice can accelerate the decay of climate signals in δ¹⁸O and δD by short-circuiting the slow isotopic diffusion in crystal grains. This theory for "excess diffusion" has not been confirmed experimentally. We show that, if the mechanism occurs, then distinct isotopic patterns must form near grain junctions, offering a testable prediction of the theory. We calculate the patterns and describe an experimental scheme for testing ice-core samples for the mechanism.

Computer models, like those used in climate change studies, are written by modellers who have to decide how best to construct the models in order to satisfy the purpose they serve. Using snow modelling as an example, we examine the process behind the decisions to understand what motivates or limits modellers in their decision-making. We find that the context in which research is undertaken is often more crucial than scientific limitations. We argue for more transparency in our research practice.

Arctic sea ice is thinning and retreating because of global warming. Thus, the region is transitioning to a new state featuring an expansion of the marginal ice zone, a region where mobile ice interacts with waves from the open ocean. By analyzing 30 years of sea ice reconstructions that combine numerical models and observations, this paper proves that an ensemble of global ocean and sea ice reanalyses is an adequate tool for investigating the changing Arctic sea ice cover.

Lakes are common features in Arctic permafrost areas. Land cover change following their drainage needs to be monitored since it has implications for ecology and the carbon cycle. Satellite data are key in this context. We compared a common vegetation index approach with a novel land-cover-monitoring scheme. Land cover information provides specific information on wetland features. We also showed that the bioclimatic gradients play a significant role after drainage within the first 10 years.

The grounding line, where ice begins to float, is an essential variable to understand ice dynamics, but in some locations it can be challenging to measure with established techniques. Using satellite data and a new method, Wallis et al. measure the grounding line position of glaciers and ice shelves in the Antarctic Peninsula and find retreats of up to 16.3 km have occurred since the last time measurements were made in the 1990s.

Thermo-erosion gullies (TEGs) are one of the most common forms of abrupt permafrost degradation. While their inception has been examined in several studies, the processes of their stabilization remain poorly documented. For this study, we investigated two TEGs in the Canadian High Arctic. We found that, while the formation of a TEG leaves permanent geomorphological scars in landscapes, in the long term, permafrost can recover to conditions similar to those pre-dating the initial disturbance.

We present the first explicit three-dimensional simulations of sea-ice ridge formation, which enables us to observe failure in several locations simultaneously. Sea-ice ridges are formed when ice converges and fails due to wind and ocean currents, so broken ice accumulates in a ridge. Previous two-dimensional models could not capture this behavior. We conclude that non-simultaneous failure is necessary to simulate ridging forces to assess how ridging forces relate to other ice properties.

It is crucial to consider organized structures such as turbulence sweeps and ejections when discussing the onset and development of snow transport. This study aims to systematically measure blowing and drifting snow to investigate their spatiotemporal structures. To achieve this goal, we have deployed 15 snow particle counters (SPCs) in designated test areas and are conducting measurements using an equal number of ultrasonic anemometers, providing high-temporal-resolution data.

Retrogressive thaw slumps (RTSs) are widespread in the Arctic permafrost landforms. RTSs present a big interest for researchers because of their expansion due to climate change. There are currently different scientific schools and terminology used in the literature on this topic. We have critically reviewed existing concepts and terminology and provided clarifications to present a useful base for experts in the field and ease the introduction to the topic for scientists who are new to it.

Mechanical damage to stalagmites is commonly observed in mid-latitude caves. In this study we investigate ice flow along the cave bed as a possible mechanism for stalagmite damage. Utilizing models which simulate forces created by ice flow, we study the structural integrity of different stalagmite geometries. Our results suggest that structural failure of stalagmites caused by ice flow is possible, albeit unlikely.

The melting of ice mélange, or dense packs of icebergs and sea ice in glacial fjords, can influence the water column by releasing cold fresh water deep under the ocean surface. However, direct observations of this process have remained elusive. We use measurements of ocean temperature, salinity, and velocity bookending an episodic ice mélange event to show that this meltwater input changes the density profile of a glacial fjord and has implications for understanding tidewater glacier change.

The Greenland ice sheet largely depends on the climate state. The uncertainties associated with the year-to-year variability have only a marginal impact on our simulated surface mass budget; this increases our confidence in projections and reconstructions. Basing the simulations on proxies, e.g., temperature, results in overestimates of the surface mass balance, as climatologies lead to small amounts of snowfall every day. This can be reduced by including sub-monthly precipitation variability.

The complex geomorphology of southeast Greenland (SEG) creates dynamic fjord habitats for top marine predators, featuring glacier-derived floating ice, pack and landfast sea ice, and freshwater flux. We study the physical environment of SEG fjords, focusing on surface ice conditions, to provide a regional characterization that supports biological research. As Arctic warming persists, SEG may serve as a long-term refugium for ice-dependent wildlife due to the persistence of regional ice sheets.

Terrain formerly occupied by ice sheets in the last ice age allows us to parameterize models of basal water flow using terrain and data unavailable beneath current ice sheets. Using GlaDS, a 2D basal hydrology model, we explore the origin of murtoos, a specific landform found throughout Finland that is thought to mark the upper limit of channels beneath the ice. Our results validate many of the predictions of murtoo origins and demonstrate that such models can be used to explore past ice sheets.

Our study near EastGRIP camp in Greenland shows varying firn properties by direction (crucial for studying ice stream stability, structure, surface mass balance, and past climate conditions). We used dispersion curve analysis of Love and Rayleigh waves to show firn is nonuniform along and across the flow of an ice stream due to wind patterns, seasonal variability, and the proximity to the edge of the ice stream. This method better informs firn structure, advancing ice stream understanding.