Publications

Hochreuther, P; Neckel, N; Reimann, N; Humbert, A; Braun, M (2021). Fully Automated Detection of Supraglacial Lake Area for Northeast Greenland Using Sentinel-2 Time-Series. REMOTE SENSING, 13(2), 205.

Abstract
The usability of multispectral satellite data for detecting and monitoring supraglacial meltwater ponds has been demonstrated for western Greenland. For a multitemporal analysis of large regions or entire Greenland, largely automated processing routines are required. Here, we present a sequence of algorithms that allow for an automated Sentinel-2 data search, download, processing, and generation of a consistent and dense melt pond area time-series based on open-source software. We test our approach for a similar to 82,000 km(2) area at the 79 degrees N Glacier (Nioghalvfjerdsbrae) in northeast Greenland, covering the years 2016, 2017, 2018 and 2019. Our lake detection is based on the ratio of the blue and red visible bands using a minimum threshold. To remove false classification caused by the similar spectra of shadow and water on ice, we implement a shadow model to mask out topographically induced artifacts. We identified 880 individual lakes, traceable over 479 time-steps throughout 2016-2019, with an average size of 64,212 m(2). Of the four years, 2019 had the most extensive lake area coverage with a maximum of 333 km(2) and a maximum individual lake size of 30 km(2). With 1.5 days average observation interval, our time-series allows for a comparison with climate data of daily resolution, enabling a better understanding of short-term climate-glacier feedbacks.

DOI:
10.3390/rs13020205

ISSN: