Borehole temperature reconstructions reveal differences in past surface temperature trends for the permafrost in the Laptev Sea region, Russian Arctic

Abstract

In central Siberia, past temperature changes have been driving permafrost warming in a region with large organic carbon reserves stored in the perennially frozen ground. However, local arctic temperature histories in the ice-rich permafrost areas of the remote Russian Arctic are sparsely known or based on proxy data with potential seasonal biases and underrepresented in circum-Arctic reconstructions. This study employed two inversion schemes (particle swarm optimization and a least-square method) to reconstruct temperature histories for the past 200-300 years in the Laptev Sea region from two permafrost borehole temperature records. These data were evaluated against larger scale reconstructions from the region. Distinct differences between the western Laptev Sea and the Lena Delta sites were recognized, such as a transition to warmer temperatures a century later in the western Laptev Sea as well as a peak in warming 3 decades later. The local permafrost surface temperature history at Sardakh Island in the Lena Delta was reminiscent of the circum-Arctic regional average trends. However, Mamontov Klyk in the western Laptev Sea was consistent to Arctic trends only in the most recent decade and was more similar to northern hemispheric mean trends. Both sites are consistent with a rapid recent warming that is of synoptic scale. Different environmental influences such as synoptic atmospheric circulation and sea ice may be responsible for differences between the sites. The shallow permafrost boreholes provide missing well-resolved short-scale temperature information in the coastal permafrost tundra of the Arctic. As local differences from circum-Arctic reconstructions, such as later warming and higher warming magnitude, were shown to exist in this region, our results provide a basis for local surface temperature record parameterization of climate models, and in particular of permafrost models.

Microbial community composition and abundance after millennia of submarine permafrost warming

“…The temperature (Fig. 2b) of Unit II was lowest in the terrestrial borehole (C1, constantly at around −12.4 • C at the time of drilling in Junker et al, 2008, and between −12.0 and −12.5 • C recently measured over a 2-year period by Kneier et al, 2018) and increased with distance to the shore. According to Junker et al (2008) C4 exhibited a temperature range from −7.1 to −5.8 • C. Ground temperatures of C3 and C2 were similar with mean values of −1.4 and −1.5 • C, respectively, and showed marginal variation.…”

Thermokarst Lake to Lagoon Transitions in Eastern Siberia: Do Submerged Taliks Refreeze?

“…In this case, the frozen permafrost is ice‐bearing and not ice‐bonded and thus may still provide pathways for gas migration toward the surface. Considering the mean annual ground surface temperature warming observed in the region over the past few decades (Kneier et al., 2018), Polar Fox Lagoon was probably exposed to colder conditions at the onset of the lake to lagoon transition. Not surprisingly, the cool winter (Scenario 7) and cool sea (Scenario 9) scenarios predicted an IBP evolution pattern that fits better with the borehole results.…”

“…In this case, the frozen permafrost is ice-bearing and not ice-bonded and thus may still provide pathways for gas migration toward the surface. Considering the mean annual ground surface temperature warming observed in the region over the past few decades (Kneier et al, 2018), Polar Fox Lagoon was probably exposed to colder conditions at the…”

A 16-year record (2002–2017) of permafrost, active-layer, and meteorological conditions at the Samoylov Island Arctic permafrost research site, Lena River delta, northern Siberia: an opportunity to validate remote-sensing data and land surface, snow, and permafrost models

“…Marked warming of this area over the last 200 years has been inferred from temper-J. Boike et al: A 16-year record (2002Boike et al: A 16-year record ( -2017 of permafrost, active-layer, and meteorological conditions ature reconstruction using deep borehole permafrost temperature measurements in the delta and the broader Laptev Sea region (Kneier et al, 2018).…”