Video_1_Seasonal Observations at 79°N Glacier (Greenland) From Remote Sensing and in situ Measurements.MP4

• Main Authors: Niklas Neckel, Ole Zeising, Daniel Steinhage, Veit Helm, Angelika Humbert
• Format: Dataset
• Language: unknown
• Published: 2020
• Subjects: Solid Earth Sciences; Climate Science; Atmospheric Sciences not elsewhere classified; Exploration Geochemistry; Inorganic Geochemistry; Isotope Geochemistry; Organic Geochemistry; Geochemistry not elsewhere classified; Igneous and Metamorphic Petrology; Ore Deposit Petrology; Palaeontology (incl. Palynology); Structural Geology; Tectonics; Volcanology; Geology not elsewhere classified; Seismology and Seismic Exploration; Glaciology; Hydrogeology; Natural Hazards; Quaternary Environments; Earth Sciences not elsewhere classified; Evolutionary Impacts of Climate Change; Greenland; 79°N glacier; seasonal glacier speed-up; GPS; remote sensing; supraglacial lake drainage; Nioghalvfjerdsfjorden; Rapid Lake; East Greenland; glacier
• Online Access: https://doi.org/10.3389/feart.2020.00142.s002; https://figshare.com/articles/Video_1_Seasonal_Observations_at_79_N_Glacier_Greenland_From_Remote_Sensing_and_in_situ_Measurements_MP4/12377705

This study investigates seasonal ice dynamics of Nioghalvfjerdsfjorden or 79°N Glacier, one of the major outlet glaciers of the North East Greenland Ice Stream. Based on remote sensing data and in-situ GPS measurements we show that surface melt water is quickly routed to the ice-bed interface with a direct response on ice velocities measured at the surface. From the temporally highly resolved GPS time series we found summer peak velocities of up to 22% faster than their winter baseline. These average out to 9% above winter velocities when relying on temporally lower resolved velocity estimates from TerraSAR-X intensity offset tracking. From our GPS time series we also found short term ice acceleration after the melt season. By utilizing optical satellite imagery and interferometrically derived digital elevation models we were able to link the post melt season speed-up to a rapid lake drainage event (<24 h) with an estimated drainage volume of 28 × 10 6 m 3 . We further highlight that GPS measurements are needed to resolve short term velocity fluctuations with low amplitudes, whereas remote sensing estimates are rather useful for the calculation of general trends in velocity behavior.