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Increasing air temperatures in the Arctic cause permafrost to thaw, releasing carbon dioxide and methane into the atmosphere. Carbon in thawing permafrost is released approximately three times more readily when soils are unsaturated versus saturated. Therefore, understanding if the Arctic is wetting or drying as permafrost thaws is crucial to predicting soil carbon emissions. In upland permafrost regions, near‐surface soil moisture is influenced by unchannelized curvilinear zones of enhanced saturation known as water tracks. The ground underneath water tracks can collapse into thermoerosional gullies, altering their thaw depth and seasonal saturation. Water tracks and thermoerosional gullies frequently occur together on upland hillslopes but exhibit heterogeneous saturation dynamics. Thus, understanding saturation states in water tracks and gullies is crucial to predicting soil carbon emissions. In this study, we quantify saturation across water tracks and a gully and examine changes in near‐surface saturation metrics over time by leveraging ~30 years of meteorological data and remotely sensed wetness indices from Landsat (1994–2023) and PlanetScope (2017–2023) imagery for a permafrost hillslope on the North Slope of Alaska, USA. Results suggest that the studied water tracks are drying following the ground collapse event, decreasing the overall saturated area proximal to the collapse, but that the water tracks still have relatively high mean Normalised Difference Water Index (NDWI) values for all rainfall magnitudes. Given the importance of soil saturation for predicting carbon emissions, the results of this work may provide tools for improving estimates of carbon release from thawing continuous permafrost hillslopes. 

Abstract. Rock fractures are a key contributor to a broad array of Earth surface processes due to their direct control on rock strength as well as rock porosity and permeability. However, to date, there has been no standardization for the quantification of rock fractures in surface process research. In this work, the case is made for standardization within fracture-focused research, and prior work is reviewed to identify various key datasets and methodologies. Then, a suite of standardized methods is presented as a starting “baseline” for fracture-based research in surface process studies. These methods have been shown in pre-existing work from structural geology, geotechnical engineering, and surface process disciplines to comprise best practices for the characterization of fractures in clasts and outcrops. This practical, accessible, and detailed guide can be readily employed across all fracture-focused weathering and geomorphology applications. The wide adoption of a baseline of data collected using the same methods will enable comparison and compilation of datasets among studies globally and will ultimately lead to a better understanding of the links and feedbacks between rock fracture and landscape evolution. 

Abstract The Arctic has warmed three times the rate of the global average, resulting in extensive thaw of perennially frozen ground known as permafrost. While it is well understood that permafrost thaw will continue and likely accelerate, thaw rates are nonuniform due, in part, to the expansion of Arctic trees and tall shrubs that may increase ground temperatures. However, in permafrost regions with short‐stature vegetation (height < 40 cm), our understanding of how ground temperature regimes vary by vegetation type is limited as these sites are generally found in remote high‐latitude regions that lack in situ ground temperature measurements. This study aims to overcome this limitation by leveraging in situ shallow ground temperatures, remote sensing observations, and topographic parameters across 22 sites with varying types of short‐stature vegetation on Baffin Island, Canada, a remote region underlain by rapidly warming continuous permafrost. Results suggest that the type of short‐stature vegetation does not necessarily correspond to a distinct shallow ground temperature regime. Instead, in permafrost regions with short‐stature vegetation, factors that control snow duration, such as microtopography, may have a larger effect on evolving ground temperature regimes and thus permafrost vulnerability. These findings suggest that anticipating permafrost thaw in regions of short‐stature vegetation may be more nuanced than previously suggested.