Применение космических снимков в исследованиях постпирогенных территорий Северо-Западного Прикаспия

Abstract

The paper considers the experience of using space imagery materials from the Landsat 8 satellite to determine the values of the earth's surface temperatures according to the data of the thermal infrared channel. This experience is important in identifying the factors contributing to the emergence of steppe fires, assessing their consequences in the arid climate of the South of Russia. An analysis of multi-season space images (SI) for the period 2018-2020 was carried out covering the largest fires in terms of area located on the territory of the Tersko-Kuma lowland. SI were selected according to the principle - the scenes preceding the fire event and after it in different seasons of the year. Fires were visually identified at the SI and linear profiles were laid. Linear profiles at the SI were laid in such a way as to cover equally the territory subjected to fires and the non-burnt part of the landscape. The length of the profile was 1 km, the points were laid with an interval of one pixel (30 m) and the same width. The direction of the profile is from north to south, taking into account the uniformity of the relief, landscape and land use. As a result, for the analyzed segments, using QGIS3, the temperature of the underlying surface was measured for each point of the profile. It has been established that the temperature regime of the coastal strip differs from the continental part, which is associated with the proximity of water bodies, the hydromorphism of soil and vegetation, and the shift in vegetation periods. In the natural state before the fire, the vegetation largely levels the temperature background of the surface due to the partial shading of the surface and the formation of special microclimatic conditions in the near-surface layer. The data obtained from post-fire images indicate that the temperature differences between the burnt and unburned areas are maximum in summer (up to 4 °C) and persist throughout all warm seasons of the year, up to the onset of constant negative temperatures.