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Abstract. Surface meltwater on ice shelves can exist as slush, it can pond in lakes orcrevasses, or it can flow in surface streams and rivers. The collapse of theLarsen B Ice Shelf in 2002 has been attributed to the sudden drainage of∼3000 surface lakes and has highlighted the potential forsurface water to cause ice-shelf instability. Surface meltwater systems havebeen identified across numerous Antarctic ice shelves, although the extentto which these systems impact ice-shelf instability is poorly constrained.To better understand the role of surface meltwater systems on ice shelves,it is important to track their seasonal development, monitoring thefluctuations in surface water volume and the transfer of water acrossice-shelf surfaces. Here, we use Landsat 8 and Sentinel-2 imagery to tracksurface meltwater across the Nivlisen Ice Shelf in the 2016–2017 meltseason. We develop the Fully Automated Supraglacial-Water Tracking algorithmfor Ice Shelves (FASTISh) and use it to identify and track the developmentof 1598 water bodies, which we classify as either circular or linear. Thetotal volume of surface meltwater peaks on 26 January 2017 at 5.5×107 m3. At this time, 63 % of the total volume is held withintwo linear surface meltwater systems, which are up to 27 km long, areorientated along the ice shelf's north–south axis, and follow the surfaceslope. Over the course of the melt season, they appear to migrate away fromthe grounding line, while growing in size and enveloping smaller waterbodies. This suggests there is large-scale lateral water transfer throughthe surface meltwater system and the firn pack towards the ice-shelf frontduring the summer. 

ABSTRACT The localization of stellar-mass binary black hole mergers using gravitational waves is critical in understanding the properties of the binaries’ host galaxies, observing possible electromagnetic emission from the mergers, or using them as a cosmological distance ladder. The precision of this localization can be substantially increased with prior astrophysical information about the binary system. In particular, constraining the inclination of the binary can reduce the distance uncertainty of the source. Here, we present the first realistic set of localizations for binary black hole mergers, including different prior constraints on the binaries’ inclinations. We find that prior information on the inclination can reduce the localization volume by a factor of 3. We discuss two astrophysical scenarios of interest: (i) follow-up searches for beamed electromagnetic/neutrino counterparts and (ii) mergers in the accretion discs of active galactic nuclei.