The history of permafrost landscape map compilation is related to the study of ecological problems with permafrost. Permafrost-landscape studies are now widely used in geocryological mapping. Permafrost-landscape classifications and mapping are necessary for studying the trends in development of the natural environment in northern and high-altitude permafrost regions. The cryogenic factor in the permafrost zone plays a leading role in the differentiation of landscapes, so it must be considered during classification construction. In this study, a map’s special content was developed using publications about Yakutian nature, archive sources from academic institutes, the interpretation of satellite images, and special field studies. Overlays of 20 types of terrain, identified by geological and geomorphological features, and 36 types of plant groupings, allowed the systematization of permafrost temperature and active layer thickness in 145 landscape units with relatively homogeneous permafrost-landscape conditions in the Sakha (Yakutia) Republic. This map serves as a basis for applied thematic maps related to the assessment and forecast of permafrost changes during climate warming and anthropogenic impacts.

Eight surface observation sites providing quasi-continuous measurements of atmospheric methane mixing ratios have been operated since the mid-2000's in Siberia. For the first time in a single work, we assimilate 1 year of these in situ observations in an atmospheric inversion. Our objective is to quantify methane surface fluxes from anthropogenic and wetland sources at the mesoscale in the Siberian lowlands for the year 2010. To do so, we first inquire about the way the inversion uses the observations and the way the fluxes are constrained by the observation sites. As atmospheric inversions at the mesoscale suffer from mis-quantified sources of uncertainties, we follow recent innovations in inversion techniques and use a new inversion approach which quantifies the uncertainties more objectively than the previous inversion systems. We find that, due to errors in the representation of the atmospheric transport and redundant pieces of information, only one observation every few days is found valuable by the inversion. The remaining high-resolution quasi-continuous signal is representative of very local emission patterns difficult to analyse with a mesoscale system. An analysis of the use of information by the inversion also reveals that the observation sites constrain methane emissions within a radius of 500 km. More observation sites than the ones currently in operation are then necessary to constrain the whole Siberian lowlands. Still, the fluxes within the constrained areas are quantified with objectified uncertainties. Finally, the tolerance intervals for posterior methane fluxes are of roughly 20 % (resp. 50 %) of the fluxes for anthropogenic (resp. wetland) sources. About 50–70 % of Siberian lowlands emissions are constrained by the inversion on average on an annual basis. Extrapolating the figures on the constrained areas to the whole Siberian lowlands, we find a regional methane budget of 5–28 TgCH₄ for the year 2010, i.e. 1–5 % of the global methane emissions. As very few in situ observations are available in the region of interest, observations of methane total columns from the Greenhouse Gas Observing SATellite (GOSAT) are tentatively used for the evaluation of the inversion results, but they exhibit only a marginal signal from the fluxes within the region of interest.

Climate change and the degradation of permafrost prove to be severe challenges for humanity. At present, the northern communities and those living in rural areas are already facing the consequences. This article is based on field research conducted in the Yunkyur, Olyokminsky, and Amginsky Districts of Sakha Republic (Yakutia) during 2018–2020. These settlements have one of the richest agricultural traditions in the region; however, the inhabitants of these villages now face serious consequences of permafrost degradation. The authors rely on a mixed set of methods and approaches, including sociological surveys, expert and in-depth interviewing, and appropriate archival and museum materials. Methodology of remote sensing and landscape–geocryological research was integrated. The resulting studies made it possible to demonstrate increasingly widespread thermokarst processes in the key areas studied. The authors determined that the degradation of permafrost has led to problems with the safety and development of the housing stock, especially deformation of houses and outbuildings, and reduction of areas suitable for construction. Territories affected by thermokarst also drop out of agricultural use. Finally, the authors identify some adaptation mechanisms to mitigate the effects of changes in permafrost landscapes.

A fermion field is investigated with the interaction Lagrangian density equal to $g\left(\overline{\psi }{O}_j\psi \right)·\left(\overline{\psi }{O}_j\psi \right)$. This point interaction is considered as a limit of an extended one, where it is supposed that the interaction vanishes if the momentum of a particle exceeds $\Lambda$ and/or if the momentum transferred in a collision of two particles exceeds $\lambda$. The relation between $\Lambda$ and $\lambda$ is such as to make the quantity $\frac{{\lambda }^2}{\ln \left(\frac{\Lambda }{\lambda }\right)}$ arbitrarily small as $\lambda \to \infty$ and $\Lambda \to \infty$. This choice of the limiting procedure considerably simplifies the investigation of the theory. It is shown that in the limit $\lambda \to \infty$, $\Lambda \to \infty$, the physical interaction between particles vanishes in all types of four-fermion interactions. The case of two interacting fields $\psi$ and $\chi$ with different isotopic spin is also considered. Going over to the local theory, the physical interaction vanishes in this case as well.

Rapid permafrost degradation is observed in northern regions as a result of climate change and expanding economic development. Associated increases in active layer depth lead to thermokarst development, resulting in irregular surface topography. In Central Yakutia, significant areas of the land surface have been deteriorated by thermokarst; however, no mitigation or land rehabilitation efforts are undertaken. This paper presents the results of numerical modeling of the thermal response of permafrost to changes in the active layer hydrothermal regime using field data from the village of Amga, Republic of Sakha (Yakutia), and mathematical analysis. The results suggest that restoring a thick ice-enriched layer will require increasing the pre-winter soil moisture contents in order to increase the effective heat capacity of the active layer. Snow removal or compaction during the winter is recommended to maximize permafrost cooling. The thickness of the restored transition layer varies from 0.3 to 1.3 m depending on soil moisture contents in the active layer. The modeling results demonstrate that damaged lands can be restored through a set of measures to lower the subsurface temperatures. A combination of the insulating layer (forest vegetation) and the high heat capacity layer (transition layer) in the atmosphere–ground system would be more effective in providing stable geocryological conditions.