METHOD OF USING UNMANNED AERIAL SYSTEMS FOR ASSESSMENT OF MORPHOMETRIC CHARACTERISTICS OF AUFEIS
A.A. Ostashov1, O.M. Makarieva1, A.V. Mazurok2, N.V. Nesterova1, A.A. Zemlianskova1
1Saint Petersburg State University, Saint Petersburg, Russia
2AFS Lider LLC, Saint Petersburg, Russia
Keywords: aufeis, Anmangyndinskaya aufeis, unmanned aerial systems, aerial photography, aufeis volume, aufeis area
Abstract
Aufeis are widespread in the permafrost zone. Morphometric characteristics are indicators of the aufeis dynamics and can be used in theoretical research and for practical purposes. Their assessment is associated with technical difficulties, significant time and labor costs when using contact field methods. In this paper, we propose a technique for determining the area and volume of aufeis by aerial photography using post-processing of data from global navigation satellite systems. It makes it possible to achieve centimeter accuracy in determining altitude and plan coordinates. The areas and volumes of the object on the dates of surveys were calculated based on the data of field work at the Anmangyndinskaya aufeis during 2021-2023. A total of 21 aerial photographs were processed during both the formation and melting periods of aufeis using unmanned aerial systems and materials from high-precision ground geodetic profiles. The maximum ice volume varied from 6.71 million m3 on 30.03.2023 to 5.17 million m3 on 24.03.2022, and amounted to 5.41 million m3 on 24.05.2021. The calculated weighted average of ice thickness varies from 0.50 to 1.69 m. The mean error in determining the average aufeis thickness by aerial photography compared to ground-based geodetic measurements is 11 % after identifying and adjusting for the systematic error. A comparative analysis of the aufeis area was performed using Sentinel-2 satellite images and aerial photography. The error in determining the area using space images during the snow-free period is 11 %, and during the period of snow cover - 38 %.
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