Analiza zachmurzenia na zobrazowaniach Landsat 8 w latach 2013‑2020 jako ocena stopnia ich przydatności w monitoringu arktycznych lodowców = Analysis of cloud cover on the 2013‑2020 Landsat 8 imagery as an assessment of its usefulness in monitoring of the High-Arctic tidewater glacier

Abstract

The main aim of the presented work was to assess Landsat 8 satellite imagery for the presence of cloud cover over the terminal zone of the Aavatsmark Glacier (NW Spitsbergen, Svalbard). The work used all downloadable Landsat 8 imagery taken from the start of the mission (early 2013) to the end of 2020 and covering the entire area of interest (AOI). There were a total of 868 satellite images. The degree of visibility of the AOI zone in each image was calculated using Quality Assessment Band image (QA), which is an integral part of the Landsat 8 dataset. The QA data were reclassified, grouped into specific visibility classes and presented on an annual and monthly basis. An analysis of the incidence of usable imagery, i.e. imagery with no more than 5% cloud cover, was also carried out. Of all the available imagery, over the years analysed, only 176 (approx. 20%) contained a fully visible area, while approx. 60% of the images had more than 95% cloud cover. These data were also compared with the results of cloud cover at the nearest weather station in Ny-Ålesund.