Reporting characteristics for the upper 100 cm of the pedon is common for Gelisols and soil C budgets. The amount of soil organic carbon (SOC) sequestered at a depth of 100 to 200 cm was determined for 29 permafrost‐affected soils from northern Alaska. An average of 29 kg C m −3 was present within the 100‐ to 200‐cm depth interval, which is contained in the upper permafrost. For a 200‐cm‐deep profile, about 36% of the SOC pool occurs below 100 cm. From limited data, there were no significant differences in “deep” SOC levels among Histels, Turbels, and Orthels, the three suborders of Gelisols. Based on a previous survey of the Barrow Peninsula, permafrost‐affected soils contain 66.5 Tg of SOC in the upper 100 cm, and another 36 Tg in the 100‐ to 200‐cm zone. This C pool is vulnerable to mobilization following warming and increased summer thaw depth in the arctic.
Lake surface temperature (LST) is a significant indicator of lake physical states and energy fluxes. This paper integrates multi-dates Landsat 8 thermal data with extensive in situ measurements to retrieve LST of Alaska lakes, and analyses temperature patterns across spatial scales, intra and inter-lakes. Our analysis shows that inside a lake, LST is relatively homogeneous and largely isothermal under strong wind, while larger temperature difference may exist during calm days. Warmer or cooler temperature gradients along wind direction are found for both coastal and inland lakes. At regional scale, small, deep lakes and lakes in inland and/or southern latitude are more likely to have higher mean temperatures across western ACP during summer season.
Abstract. Seasonal snowpack is an important predictor of the water resources available in the following spring and early-summer melt season. Total basin snow water equivalent (SWE) estimation usually requires a form of statistical analysis that is implicitly built upon the Gaussian framework. However, it is important to characterize the non-Gaussian properties of snow distribution for accurate large-scale SWE estimation based on remotely sensed or sparse ground-based observations. This study quantified non-Gaussianity using sample negentropy; the Kullback–Leibler divergence from the Gaussian distribution for field-observed snow depth data from the North Slope, Alaska; and three representative SWE distributions in the western USA from the Airborne Snow Observatory (ASO). Snowdrifts around lakeshore cliffs and deep gullies can bring moderate non-Gaussianity in the open, lowland tundra of North Slope, Alaska, while the ASO dataset suggests that subalpine forests may effectively suppress the non-Gaussianity of snow distribution. Thus, non-Gaussianity is found in areas with partial snow cover and wind-induced snowdrifts around topographic breaks on slopes and on other steep terrain features. The snowpacks may be considered weakly Gaussian in coastal regions with open tundra in Alaska and alpine and subalpine terrains in the western USA if the land is completely covered by snow. The wind-induced snowdrift effect can potentially be partitioned from the observed snow spatial distribution guided by its Gaussianity.
Abstract Soil tongues, or soil fingers, have been identified along the walls of an active gravel pit in northeastern Indiana. Locally enhanced pedogenesis, primarily carbonate leaching and clay illuviation, has resulted in wedge- and cone-shaped extensions of the B horizon into the underlying calcareous glaciofluvial sediments. Although previously described in the literature, the features at this site are considered unusual both for the numerous well-defined tongues and for the regularity of tongue spacing, which gives the illuviation front the appearance of a high-amplitude sinusoidal wave train. Depth to the illuviation front was measured at 0.25-m intervals along a 40-m exposure. Statistical tests indicate that the spatial pattern is nonrandom. The data were transformed using Fourier methods, and the resulting variance spectrum show a peak intensity at wavelengths bracketing 1.5 m. The results of these analyses suggest a surficial or near-surface topographic control. Climatic conditions following local glacier recession favored periglacial activity, and there is some evidence to suggest development of thermal contraction cracks and nonsorted or poorly sorted polygons 1.5 m in diameter. As an alternative hypothesis, laboratory experiments suggest that regularly spaced fingers can develop in homogeneous materials when instability occurs at the wetting front. In this case, soil tongues cannot be used as relict indicators of periglacial activity.
Abstract A traditional knowledge “Iñupiaq Web GIS”, based on a five‐year study and containing observations and environmental knowledge of Iñupiat communities indigenous to Arctic Alaska, was incorporated into a Web‐based platform. The website, “Arctic Cultural Cartography,” was created to be an open portal through which the password‐protected “Iñupiaq Web GIS” could be accessed. We discuss the process of developing the web GIS including the incorporation of user‐friendly features such as links to interactive maps, video clips of interviews, discussion boards, and the integration of popular web interfaces such as Facebook. We also discuss short‐ and long‐term goals for the further development of the GIS, its potential as a sustainable, participatory online database for sharing pertinent ecological knowledge, and challenges in achieving optimal community involvement given constraints imposed by remote locations with limited bandwidth.
The cryosphere refers to the Earth’s frozen realm. As such, it includes the 10 percent of the terrestrial surface covered by ice sheets and glaciers, an additional 14 percent characterized by permafrost and/or periglacial processes, and those regions affected by ephemeral and permanent snow cover and sea ice. Although glaciers and permafrost are confined to high latitudes or altitudes, areas seasonally affected by snow cover and sea ice occupy a large portion of Earth’s surface area and have strong spatiotemporal characteristics. Considerable scientific attention has focused on the cryosphere in the past decade. Results from 2 ×CO2 General Circulation Models (GCMs) consistently predict enhanced warming at high latitudes, especially over land (Fitzharris 1996). Since a large volume of ground and surface ice is currently within several degrees of its melting temperature, the cryospheric system is particularly vulnerable to the effects of regional warming. The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) states that there is strong evidence of Arctic air temperature warming over land by as much as 5 °C during the past century (Anisimov et al. 2001). Further, sea-ice extent and thickness has recently decreased, permafrost has generally warmed, spring snow extent over Eurasia has been reduced, and there has been a general warming trend in the Antarctic (e.g. Serreze et al. 2000). Most climate models project a sustained warming and increase in precipitation in these regions over the twenty-first century. Projected impacts include melting of ice sheets and glaciers with consequent increase in sea level, possible collapse of the Antarctic ice shelves, substantial loss of Arctic Ocean sea ice, and thawing of permafrost terrain. Such rapid responses would likely have a substantial impact on marine and terrestrial biota, with attendant disruption of indigenous human communities and infrastructure. Further, such changes can trigger positive feedback effects that influence global climate. For example, melting of organic-rich permafrost and widespread decomposition of peatlands might enhance CO2 and CH4 efflux to the atmosphere. Cryospheric researchers are therefore involved in monitoring and documenting changes in an effort to separate the natural variability from that induced or enhanced by human activity.
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