This article examines alases (thermokarst features) in the Lena-Aldan interfluve representing a classic area of permafrost landscapes. A GIS project was created in ArcGIS format. The definition of alases (alas terrain types) is given as distinctive periglacial landforms that reflect the history of the study area. The purpose of the work was to analyze the spatial distribution of alas landforms in the Churapcha Ulus (District) within the major geomorphological elements using digitization methods, geoprocessing, contour verification, and point density analysis. This was performed using Sas.Planet, ArcGIS Earth, and Spatial Analist programs and applications. Alas orientation, depth and size were determined, and elevation profiles were constructed. The spatial analysis revealed the patterns of alas distribution and defined the municipalities with higher alas densities. Coalesced alas groups over 75 ha in size are most common in the Churapcha Ulus, while large (20–75 ha) and medium (1–20 ha) alases occupy 30 and 11% of the region, respectively. Alases are less frequent in the south and southeast of the region compared to its central part where the alas density is high. The results of the spatial analysis are presented in the form of maps and diagrams.

Yaroslav I. Torgovkin
Candidate of Geographical Sciences,
Head of the Laboratory of Geographic Information Systems (GIS) and Permafrost Mapping
Melnikov Permafrost Institute of Siberian Branch of the Russian Academy of Sciences
36, Merzlotnaya str., Yakutsk, 677010, Russia
e-mail: torgovkin@mpi.ysn.ru
ORCID: 0000-0002-7146-0798
SCOPUS ID: 6504170111
Researcher ID: AAD-2134-2019
SPIN-код: 4667-8312
AuthorID: 120968

Aliona A Shestakova
Candidate of Geographical Sciences,
Senior Researcher of the Laboratory of Geographic Information Systems (GIS) and Permafrost Mapping
Melnikov Permafrost Institute of Siberian Branch of the Russian Academy of Sciences
36, Merzlotnaya str., Yakutsk, 677010, Russia
e-mail: aashest@mail.ru
ORCID: 0000-0002-0648-0362
SCOPUS ID: 57207798418
Researcher ID: Y-9063-2018
SPIN-код: 3811-5061
AuthorID: 543724

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