Features of the methodology for studying the dynamics of tidal rivers deltas in the northern regions using satellite images 
 (the Northern Dvina as example)

Using satellite images from the KeyHole 1977 and Sentinel-2B 2020 satellites, the dynamics of the tidal delta of the Northern Dvina River was investigated. When choosing images, it is necessary to take into account seasonal and tidal fluctuations in the water level; images for the dry season with a close tide phase at the moments of shooting in different years were selected. The first compiled map of delta dynamics for the period 1977–2020 shows that the growth of delta, noted by researchers earlier, continues – the attachment of islands along the sea edge to it, the accumulation of sediments and an increase in the area of channel islands in the main river-branches, narrowing and disappearance of small streams on the delta islands. But to the long-term tendency of delta growth, the processes of erosion of the coast on the islands of the sea edge are added from the side of the Dvina Bay.