Sub‐annual moraine formation at an active temperate Icelandic glacier

This paper presents detailed geomorphological and sedimentological investigations of small recessional moraines at Fjallsjökull, an active temperate outlet of Öræfajökull, southeast Iceland. The moraines are characterised by striking sawtooth or hairpin planforms, which are locally superimposed, giving rise to a complex spatial pattern. We recognise two distinct populations of moraines, namely a group of relatively prominent moraine ridges (mean height ~1.2 m) and a group of comparatively low‐relief moraines (mean height ~0.4 m). These two groups often occur in sets/systems, comprising one pronounced outer ridge and several inset smaller moraines. Using a representative subsample of the moraines, we establish that they form by either (i) submarginal deformation and squeezing of subglacial till or (ii) pushing of extruded tills. Locally, proglacial (glaciofluvial) sediments are also incorporated within the moraines during pushing. For the first time, to our knowledge, we demonstrate categorically that these moraines formed sub‐annually using repeat uncrewed aerial vehicle (UAV) imagery. We present a conceptual model for sub‐annual moraine formation at Fjallsjökull that proposes the sawtooth moraine sequence comprises (i) sets of small squeeze moraines formed during melt‐driven squeeze events and (ii) larger push moraines formed during winter re‐advances. We suggest the development of this process‐form regime is linked to a combination of elevated temperatures, high surface meltwater fluxes to the bed, and emerging basal topography (a depositional overdeepening). These factors result in highly saturated subglacial sediments and high porewater pressures, which induces submarginal deformation and ice‐marginal squeezing during the melt season. Strong glacier recession during the summer, driven by elevated temperatures, allows several squeeze moraines to be emplaced. This process‐form regime may be characteristic of active temperate glaciers receding into overdeepenings during phases of elevated temperatures, especially where their englacial drainage systems allow efficient transfer of surface meltwater to the glacier bed near the snout margin

Localized practices and globalized futures: challenges for Alaska coastal community youth

An article from Maritime Studies (2015) 14:

Analyzing ice dynamics using Sentinel-1 data at the Solheimajoküll Glacier, Iceland

The climate in southern Iceland has warmed over the last 70 years, resulting in accelerated glacier dynamics at the Solheimajoküll glacier. In this study, we compare glacier terminus locations from 1973 to 2018, to changes in climate across the study area, and we derive ice-surface velocities (2015–2018) from satellite remote-sensing imagery (Sentinel-1) using the offset-tracking method. There have been two regional temperature trends in the study period: cooling (1973–1979) and warming (1980–2018). Our results indicate a time lag of about 20 years between the onset of glacier retreat (−53 m/year since 2000) and the inception of the warming period. Seasonally, the velocity time series suggest acceleration during the summer melt season since 2016, whereas glacier velocities during accumulation months were constant. The highest velocities were observed at high elevations where the ice-surface slope is the steepest. We tested several scenarios to assess the hydrological time response to glacier accelerations, with the highest correlations being found between one and 30 days after the velocity estimates. Monthly correlation analyses indicated inter-annual and intra-annual variability in the glacier dynamics. Additionally, we investigate the linkage between glacier velocities and meltwater outflow parameters as they provide useful information about internal processes in the glacier. Velocity estimates positively correlate with water level and negatively correlate with water conductivity between April and August. There is also a disruption in the correlation trend between water conductivity and ice velocity in June, potentially due to a seasonal release of geothermal water

Arctic observing network social indicators and northern commercial fisheries

This article presents issues and challenges associated with collecting social indicator data in the context of northern commercial fisheries. The Arctic Observing Network Social Indicators Project (AON-SIP) fisheries domain database consists of geo-coded social indicator datasets from Alaska, Iceland, Norway, and Chukotka, of place/year catch, landings, employment, and permit data from 1980-present for commercially important species above 60°N and in the Bering Sea. Comparability of indicator data across regions will be important for the future monitoring and modeling of the effects of changes in the arctic environment such as those influenced by diminishing sea ice cover and increasing ocean acidification which will impact fisheries production and distribution. Equally important, the collection and analysis of time-series social indicator data could aid in understanding how arctic residents experience the processes of globalization as they participate in industries such as fisheries that are increasingly dominated by non-local corporations. Because of this extrinsic control of resources, social indicator data reflecting local ownership in fisheries rights and revenues could be functional in understanding how changes in fisheries impact arctic livelihoods. It is also necessary to understand how changes in fisheries fit within a broader resource use and arctic development context, for example, in conjunction with the oil and gas industry. Finally, planning for arctic fisheries of the future will be dependent upon data collection and analysis activities that can inform management plans and governance structures accommodating international boundary conflicts, rights-based management regimes, indigenous access, and organization/oversight of arctic marine science initiatives