ИСТИНА

The Arctic sea ice decline is a well-known downward trend, which has shown a marked acceleration since the beginning of the 21st century. The response of small islands to these changes is still poorly understood. Regular radar survey of the Arctic territories by Sentinel-1 synthetic aperture radar (SAR) provide an opportunity to study seasonal changes independently of clouds and natural illumination. A coherence is one of the parameters calculated during interferometric processing of SAR remote sensing data. As far as it is calculated for each element of the radar data, a map of coherence is created. Such maps are proposed to use as an additional source of thematic information about the properties of a surface. Being combined with amplitude images for both dates the coherence image forms Multi-Temporal Coherence (MTC) color composites. The MTC approach has been convincingly demonstrated for monitoring activities of volcanic eruption events, for agriculture and forests. The research aimed to apply the MTC color composite approach for study the Arctic island of Vise state and its seasonal changes. Multiple interferometric Sentinel-1 data for the whole year 2019 were collected at Interferometric Wide Swath Mode, with pixel sizes of 5x20 m the processing level SLC - Single Look Complex – complex radar data containing the amplitude and phase of the signal. A total of 29 images with HH polarization were uploaded and processed completely with SNAP software packages. Visual comparison of the time series of 26 seasonal MTC images, each of which includes changes over a 12-day period, allows to interpret the state of the island surface and the adjacent water area during 2019. The images interpretation was supported by detailed weather data from the weather station located on the island. The changes in the island surface state are confirmed in general by observations of snow cover height, precipitation and air temperatures. All year MTC color composites were helpful in revealing seasonal changes that are generally consistent with weather station data. It was also possible to determine the periods when the nearest to the island water area was free of sea ice, which is important for assessing the intensity of coastal destruction.