## 2 Materials and Methods
### Remote Sensing and Spatial Data
In comparison with the previous Planet scene, the glacier-ice is already visible after the winter snow has melted. However, fresh snow is also present, mainly in the hollows of the ground. **Integration of the archival data. ** All the acquired remote sensing data have been processed by geometric and radiometric correction and completed in the ENVI software. The Universal Transverse Mercator (UTM 21S) was chosen as a common reference system, while all the images were checked and calibrated to the orthophotomap from 1979, which was prepared on the basis of aerial photographs with the highest resolution, and the orthorectification process was carried out on the basis of terrain points where the geographical coordinates were determined using the DGPS method [26; 34]. The pre-processed images (1956, 1979, 1989, 2001, and 2018) were entered into the ArcGIS project (@ ESRI, Inc., Redlands, CA, USA). The geobase was completed with vector data (SHP) representing previously determined ranges of glaciers (2001, 2007). Direct mapping using GPS permitted the precise identification of glacier margins, dead-ice zones, and perennial snow covers. Due to the high quality of the aerial photographs and satellite images (Geo-Eye1 and PlanetScope), the determination of glacier boundaries did not require advanced image analysis techniques and was carried out by the vectorization of appropriately sharpened images (histogram analysis and stretching). All images (excluding 1956 data) were gathered when the snow cover was absent (or insignificant), facilitating the high-resolution tracking of numerous features, including large-glacier fronts, small-glacier margins, and permanent snow/ice patches. The most problematic cartographic data adapted to determine the course of the glacier border (cause of the scale, 1:50,000) was the map from 1989 [33]. In order to improve spatial accuracy, archival sketches were used. This task was carried out in parallel to the first kinetic GPS survey conducted in 1999 during the 23 rd polar expedition to the Arctowski Station, where one of the co-authors of the presented study had an opportunity to personally consult on the data quality with Mr [PERSON], the map's author. The collected preliminary results served as a basis for the GIS project developed for ASPA-128 since that time and, finally, were used in this study. In the next step, the glacier ranges from all the analysed periods, coded as shapefiles, were converted to polygons, which allowed for the study of the diminishing glacier area for both types of glaciers (land-terminating and tidewater). The base map for the detailed analyses of individual glaciers is presented in Figure 5. In comparison, previous publications on the determination of glacial change in the Admiralty Bay using satellite imagery [8; 35] focused mainly on determining the retreat stages of tidewater glaciers. Some of these satellite images were taken at times when snow cover was still present and, consequently, the interpretation of glacier borders terminating on land was very difficult. The areal extent of each glacier was determined for 1979, 1989, 2001, 2007, 2011, and 2018 (Figure 5). The glacier extents based on aerial/satellite photos and maps were digitized manually with the accuracy  
Figure 5: The changes in glacier coverage during periods of 1979–1989, 1989–2001, 2001–2007, 2007–2011, and 2011–2018 in ASPA-128. The altitudes of the lowest (140 m a.s.l.) and the highest (290 m a.s.l.) reported Equilibrium-Lines Altitude (ELA) are marked on the map. Glacier zones: Dera Icefall, Wrobel Glacier (Xa), Wrobel-Italian Glacier (Xb), Ecology Glacier, Ecology-Sphinx (E–S), Rescuers Hills (R), Sphinx Glacier (Sa), Sphinx-Czajkowski Glacier (Sb), Baranowski Glacier, Tower Glacier, Thawing Glacier (Ta), Windy Glacier. The location of the photographs are shown in Appendix A Figures A2-A4 and their directions were marked in the yellow circles. limited by the resolution of materials.