Jacqueline Otto, Nina Kirchner Annual distribution and behavior of supraglacial lakes on Ryder Glacier, Northern Greenland, 1985⁠ – ⁠2020 Bolin Centre Database 2022 Datafile Terrestrial Glaciers Hydrology Supraglacial lakes Supraglacial lake drainage Greenland Greenland Ice Sheet Ryder Glacier Earth science > Cryosphere > Glaciers/ice sheets > Ice sheets Jacqueline Otto 2022-05-18T07:36:34+00:00 English 1 The dataset includes 32 lake drainage mode shapefiles (DrainageModeYEAR.shp), one file for each of the studied years between 1985⁠ – ⁠2020. Each shapefile represents the annual lake mask consisting of all identified and delineated lakes of that year´s peak of the melt season (July and August). The years 1986, 1996, 2001, 2003 were excluded from the analysis due to limited availability of required satellite imagery. An annual lake mask was created by first applying the Normalized Difference Water Index (NDWI) with a threshold ranging between 0.15⁠ – ⁠0.5 to all available largely cloud-free Landsat satellite images for July and August, by this differentiating between (non)water-covered pixels representing lake surfaces, and then combining all resulting NDWI layers to one single annual lake mask. All lake features that were then delineated from the annual lake mask present the maximum lake extent of each identified lake during that melt season. The attribute table of each shapefile contains the following information about the individual delineated lakes: **Lake area** - the lake area in km², which was calculated according to the number and size of the image pixels identified as lake surface. **Drainage Mode** - the classified mode of lake drainage/cessation over the course of the melt season. The classification is based on chronologically investigating satellite imagery from the onset to the end of the melt season (May⁠ – ⁠September). An attached xlsx spreadsheet file describes the classification key and all applied categories in detail. Additionally, a shapefile of the study area extent for the here presented lake analyses is included in the dataset (RyderAOI.shp). Lake analysis was performed for the area of grounded ice, excluding the floating tongue of Ryder Glacier. Each .shp file is accompanied by its associated complementary files defining additional formatting (.shx, .dbf, .prj etc.).